Wissenschaftliche Veröffentlichungen

The biodeterioration of concrete elements in sewer systems and their repair is of significant economic and societal concern. However, the available test methods to assess the performance of cementitious materials under the relevant conditions are insufficiently validated. In the present study, two biological test methods and a standardised chemical test were applied to two sewer repair mortars and a reference mortar, and the performances of these materials were compared in a severely deteriorating sewer environment. In both biological tests, the induction period was considerably shorter than that of the field, and time-resolved recording of durability indicators enabled to determine deterioration rates in the steady-state regime, which compared reasonably well with each other and with the behaviour in the sewer environment. The chemical test does not allow to obtain a deterioration rate, and the observed relative performance differences of the mortars deviated from the results of the biological tests.

ROBUST - Die marine Anwendungsumgebung bürdet Material und Technik zahlreiche Anforderungen auf, die es zu erfüllen gilt, um längerfristig bestehen zu können. Im BMWK-geförderten Projekt ROBUST ist die Fähigkeit zur wiederholenden Reinigung ohne Oberflächenschädigung von Offshore-Strukturen untersucht worden.

Field tests ▪ Biofouling is an unsolved problem in offshore industry, it induces a lot of work and therefore high costs ▪ It causes problems, when the welding seams of offshore-structures have to be controlled by divers regularly ▪ The industrial standard coatings should be replaced by more efficient non-biocidal systems Summarized project goals: Less fouling, easier cleanings, mechanical stability of the coating, no input of biocides into the environment and lower costs at maintenance

Poster

Die vorliegende Studie wurde vom UBA initiiert. Im Rahmen des Projektes wurden Kriterien aufgestellt, mit denen die Umweltverträglichkeit und auch die Wirksamkeit der nicht-bioziden Bewuchsschutzsysteme nachgewiesen werden muss, um das RAL-Umweltzeichen zu erlangen. Das Institut für Antifouling und Biokorrosion hat dabei die Kriterien zum Nachweis der Wirksamkeit erarbeitet.

Die Einführung eines Umweltzeichens Blauer Engel für umweltfreundliche „Unterwasserbeschichtungen und andere Bewuchsschutzsysteme“ soll nun die Etablierung dieser Produkte auf dem Markt unterstützen und gleichzeitig die Hersteller motivieren, weitere geeignete Produkte zu entwickeln.

In-water cleaning of ship hulls is widely carried out to increase ship performance, and is under intense discussion regarding regulations, quality improvement and technologies in use [2]. One critical aspect is the common practice of cleaning biocidal antifouling paints, which is incompatible with national and EU water legislation, and the impact of abrasion on antifouling coatings that are not designed for cleaning.

Additionally, the majority of cleaning operations do not filter or capture the fouled material. Furthermore, there is usually no control or verification of the quality of the cleaning technology applied. Fluorometric technologies are used to control the efficacy of capture. Ideally, the removed fouling should be captured and sucked up by the cleaning machine using a vacuum system.

In waters with high visibility, optical methods like front and aft cameras can be used. Dyes can be injected to control the efficacy photometrically [9]. Unfortunately, in ports along the North Sea and most ports of the Baltic Sea, the visibility is low and optical control methods cannot be applied, requiring other verification methods.

One option is to use the relation between fouling stage and weight of fouling as an indicator of the amount of fouling which has to be captured. Taking samples of the fouling accumulation prior to cleaning may provide a guide to the volume of fouling present on the hull and the amount to be captured.

In this way, the captured material can be compared with the earlier estimate and may provide a reasonable estimation of efficacy. To explore the validity of the relationship between fouling stage and fouling weight, data from previous fouling studies were compiled and scrutinised regarding their usefulness for such an estimation.

This paper describes the first experiences of the R+D project ROBUST with newly developed, non-biocidal and robust test coatings for Offshore constructions by the partners Fraunhofer IFAM and Momentive Performance Materials GmbH under the impact of brush cleaning and high-pressure cleaning. The test panels have been immersed by the Dr. Brill + Partner (DBP) Institute for Antifouling and Biocorrosion on the North Sea Island Norderney in different ways and have been cleaned in different intervals to simulate a long service-life. Additionally, a graduated concept of brushes has been developed to find out the best way of cleaning without damaging the surface of the hard coatings with foul-release properties. Cleaning efficacy and mechanical damages have been evaluated at regular inspections.

DYNAMISCHE PRÜFUNG  // NICHT ZULETZT DURCH DIE EU-BIOZID-RICHTLINIE SETZEN  ANTIFOULINGBESCHICHTUNGEN OFT NICHT MEHR AUSSCHLIESSLICH AUF DIE ABGABE  VON BIOZIDEN, SONDERN VERFÜGEN ZUSÄTZLICH ODER AUSSCHLIESSLICH ÜBER EINE ANTIHAFTWIRKUNG GEGENÜBER ORGANISMEN. SOLCHEN BESCHICHTUNGEN WERDEN GÄNGIGE PLATTENTESTS NICHT MEHR GERECHT. IM FORSCHUNGSPROJEKT „FOULPROTECT“ WURDE DER  „ROTOMARIN“ ENTWICKELT, DER DIE MÖGLICHKEIT BIETET, NEUARTIGE ANTIFOULING SYSTEME UNTER SIMULIERTEN DYNAMISCHEN BEDINGUNGEN ZU TESTEN UND DIE  ERFORDERLICHE MINIMALE ANSTRÖMUNG FÜR EINE SELBSTREINIGUNG ABZULESEN.

Self-cleaning coatings offer ship owners critical protection against fouling and the issues this can cause. However, the mandatory tests for these coatings do not represent real-life conditions for the intended use. A novel circular test bench, that was developed in the R&D project “FoulProtect” funded by the Federal Ministry for Economic Affairs and Energy (FKZ: 03SX370E), uses a dynamic method to obtain accurate information, for example, on the minimum speeds required to activate self-cleaning effects and prevent fouling.

Reliable data regarding the amounts of leisure boasts and number of berths in marinas are needed for the EU biocidal products regulation of antifouling products. Since for Germany such data are lacking, a national survey was initiated by the German Federal Environmental Agency. The survey counted 206279 leisure boats, of which 71% is located in freshwater, 26% in brackish water, and 3% in salt water. High densities of boats were found at the western Baltic Sea, Lower Elbe, Mecklenburg Lake District, and Lake Constance. Antifouling concentrations were measured in selected marinas. MAMPEC was used to predict antifouling concentrations, and results the compared to measured concentrations.

Um modellbasierte Prognosen von Antifouling-Wirkstoffeinträgen durch Sportboote durchzuführen, müssen im Rahmen der EU-Biozidproduktzulassung belastbare Daten zum Bestand von Sportbooten und Häfen mit ihren Liegeplätzen vorliegen. Für Deutschland waren solche repräsentativen Daten nicht verfügbar. Das Umweltbundesamt förderte eine Studie, um den Bestand an Liegeplätzen für Sportboote in Marinas und kleineren Häfen im Binnen- und Küstenbereich zu erfassen. Die bundesweite Bestandsaufnahme der Liegeplätze ergab eine Gesamtanzahl von 206.279, von denen sich 146.425 (71 %) im Süßwasser, 54.079 (26,2 %) im Brackwasser (Salinität <18%) und 5.775 (2,8 %) im Salzwasser befanden. Die Charakteristika und Formen der Sportboothäfen im Süßwasser waren sehr heterogen und entsprachen nicht dem klassischen Schema von offenen und geschlossenen Häfen. Die Anzahl der Boote an den Liegeplätzen variierte sehr stark in Abhängigkeit vom Revier und der Sportbootsaison. Als Gebiete mit hohen Liegeplatzzahlen erwiesen sich die Ostseeküste, die Unterelbe ab Hamburg, die Mecklenburger Seenplatte, die Gewässer in und um Berlin und der Bodensee mit weiteren Voralpenseen. In einem weiteren Arbeitsschritt wurden in 50 repräsentativen Sportboothäfen Wasserproben gezogen und auf die aktuell erlaubten Antifoulingbiozide und deren Abbauprodukte analysiert, um das Vorkommen von Antifoulingbioziden in der Wasserphase von Sportboothäfen im Küsten- und Binnenbereich zu dokumentieren. Im dritten Schritt wurden die gemessenen Konzentrationen mit denen verglichen, die mittels der Computermodellierung mit MAMPEC errechnet wurden. Es stellte sich heraus, dass das MAMPEC-Modell im Gegensatz zu Küstenhäfen für Süßwasserhäfen nur bedingt zuverlässig ist.

Bestandsaufnahme und wie sieht der Bewuchsschutz für die Sportbootfahrt auf Binnenseen und Küstengewässern in Zukunft aus?
Von Dr. Burkard Watermann. Die Diskussion um Antifoulinganstriche hatte begonnen, nachdem durch Untersuchungen in den 70er Jahren bekannt wurde, dass ein Austernsterben im Becken von Arcachon an der französischen Atlantikküste auf die Antifoulingfarbe der sich damals stark vergrößernden Freizeitflotte zurückzuführen war. Damals begann die Suche nach Alternativen. Segelverbände und Farbenindustrie waren sich schnell einig: Gerade in den für Flora und Fauna so wichtigen Flachwasserzonen, in denen sich die Sportboothäfen befinden, sollte die Natur so wenig wie möglich belastet werden. Zumal schnell deutlich wurde, dass auch der Mensch, der am Ende der Nahrungskette steht, von den giftigen Stoffen betroffen werden kann.
In den vergangenen Jahren ist viel geschehen. Die Industrie musste und muss in den Antifoulingfarben auf immer mehr wirksame Biozide verzichten. Durch die Umsetzung der EU-Biozid-Verordnung, die für Deutschland zum ersten Mal ein Zulassungsverfahren für technische Biozide vorsieht, besteht eine gewisse Unsicherheit darüber, welche Antifouling-Biozide in Deutschland in Zukunft noch erlaubt sein werden. Alle sogenannten „Altbiozide“, die in den vergangenen Jahrzehnten im Gebrauch waren und für die kein Neuantrag auf Zulassung gestellt wurde, sind seit 2008 verboten. Hierzu gehören Diuron, Chlorthalonil und 30 andere Biozide.

Microorganisms inhabiting hostile Arctic environments express a variety of functional phenotypes, some of clinical interest, such as haemolytic ability and antimicrobial resistance. We studied haemolytic bacterial isolates from Arctic habitats, assessing their minimum inhibitory concentration (MIC) against antimicrobials. We then performed whole genome sequencing and analysed them for features conferring antimicrobial resistance. MIC data showed that Micromonospora spp. belong to 33% non-wild type (NWT) for erythromycin and penicillin and 22% NWT for tetracycline. Both Pseudomonas spp. belong to 43% NWT for nalidixic acid and streptomycin and 29% NWT for colistin. Finally, the Pedobacter isolate was in 80% NWT for antimicrobials tested. Whole-genome sequencing analyses revealed that fluoroquinolones, tetracyclines, macrolides and penams were the most frequent drug classes against which genotypic resistance was found. Additionally, resistance genes to heavy metals and disinfectants were identified. Our research demonstrates the presence of antimicrobial resistance in bacteria from Arctic habitats and highlights the importance of conservation efforts in these environments, where anthropogenic influence is becoming more evident. Furthermore, our data suggest the possible presence of novel resistance mechanisms, which could pose a threat if the responsible genes are transferable between species or become widespread due to environmental stress and alterations brought about by climate change.

In der vorliegenden Publikation wird die Methode des Flush-Brush-Flush (FBF)-Verfahren beschrieben und die mikrobiologischen Ergebnisse der Feldstudie vorgestellt. Weitere Ergebnisse dieser Feldstudie, der Pilotstudie und ausgewählte Ergebnisse der zuvor durchgeführten Vergleichsuntersuchungen der Methodengruppe 2.0 werden Gegenstand nachfolgender Publikationen sein.

Background: Adenoviruses belong to the stable nonenveloped viruses playing an important role in healthcare-associated infections mainly causing respiratory infections and epidemic keratoconjunctivitis. Hand disinfection with alcoholic preparations is therefore one of the most important measures to prevent such viral infections in hospitals and other medical settings.

Methods: The inactivation of adenovirus type 5 by ethanol, 1- and 2-propanol, and 2 commercially available hand disinfectants was examined at different concentrations, temperatures, and pH-values.

Results: For ethanol and 1-propanol the maximum virus-inactivating properties after 30 seconds exposure were found at a concentration of 60%-70% and 50%-60%, respectively, whereas with 2-propanol no activity was observed. The virucidal activity of all alcohols and the 2 hand disinfectants examined was increased when raising the temperature from 20°C to 25°C. By increasing the pH value to 9, a strong improvement of the activity of ethanol, 1-propanol and 1 hand disinfectant was observed, whereas pH lowering resulted in decrease of activity.

Conclusions: These results demonstrate the importance of physical parameters in the inactivation of adenoviruses by alcohols and will help to improve measures to reduce adenovirus transmission in healthcare settings.

From February 11–12, 2020, the Endoscope Hygiene Experts Forum (EHEF) held a roundtable discussion on the latest topics in the area of infection prevention in endoscopy. Renowned European and American experts from different professions came together in Berlin to discuss regional variations in endoscope processing requirements to create a better understanding of related key aspects for the prevention of infections. The discussions were moderated by Holger Biering, with each session co-hosted by a subject matter expert. Each session was opened by a short presentation by a selected participant or a guest speaker. The discussion of the topic was open to all of the experts. Even though the expert meeting took place some time ago, the results of the discussions are to be shared with a broad professional audience and are briefly summarized in the following report.

Wichtige Übertragungswege für Viren, die respiratorische Infektionen oder Durchfallerkrankungen auslösen, sind neben der Tröpfcheninfektion und der Infektion durch einen direkten Körperkontakt mit infizierten Personen auch sogenannte Schmutz-/ Schmierinfektionen. Das heißt bei Durchfall, Erbrechen, Niesen oder Husten können verschiedene Oberflächen mit virushaltigen Körpersekreten infizierter Personen verunreinigt werden. Durch einen nachfolgenden Kontakt mit diesen kontaminierten Oberflächen kann dann eine Virusübertragung stattfinden, die so zu einer indirekten Infektion weiterer Personen führen kann.

Die Stabilität humanpathogener Viren auf der Fläche war immer schon von besonderem Interesse, weil bei vielen Virusinfektionen eine Übertragung der Krankheitserreger des Respirationstraktes nicht nur aerogen, sondern z. B. auch über Flächen erfolgen kann. In einer früheren Übersicht von Kramer und Mitautoren ist bereits gezeigt worden, dass die Stabilität der humanpathogenen Viren auf der Fläche recht unterschiedlich ist.1 Ganz allgemein kann formuliert werden, dass behüllte Viren mit einer Lipidmembran wesentlich weniger stabil sind als unbehüllte Viren. Wichtige Faktoren für die Stabilität der Viren in der Umwelt sind mögliche Eiweiß- und Blutzusätze, die Temperatur, die Luftfeuchtigkeit und die Art der Fläche. Nach der Übersicht von Kramer und Mitautoren liegt die Zeit bis zur Inaktivierung auf der Fläche bei behüllten Viren aus dem Bereich des Respirationstraktes und dem der blutübertragen Viren (HIV, Hepatitisviren) im Bereich von Tagen, während für unbehüllte Viren, die überwiegend aus dem Gastrointestinaltrakt stammen, sogar Wochen und Monate angegeben werden....

The Global Polio Eradication initiative has the goal to eradicate poliomyelitis worldwide. This means that poliomyelitisvirus type 1 strain LSc 2ab (PV-1) can no longer be used for the evaluation of virucidal activity of chemical disinfectants. This study evaluated murine parvovirus ATCC VR 1346 (minute virus of mice) as suitable surrogate for PV-1 when testing virucidal activity of biocides in instrument and surface disinfectants. Suspension testing in different laboratories with two commercially available active biocidal substances based on glutaraldehyde (0.01–0.25%) and peracetic acid (0.005–0.1%) with an exposure time of 30 min was performed. Both pathogens showed comparable susceptibility and dose-dependent reduction of virus titres following German and European Guidelines.

Background: The approval of ethanol by the Biocidal Products Regulation has been under evaluation since 2007. This follows concern over alcohol uptake from ethanol-based hand rubs (EBHR). If ethanol is classified as carcinogenic, mutagenic, or reprotoxic by the European Chemicals Agency (ECHA), then this would affect infection prevention and control practices.

Aim: A review was performed to prove that ethanol is toxicological uncritical and indispensable for hand antisepsis because of its unique activity against non-enveloped viruses and thus the resulting lack of alternatives. Therefore, the following main points are analyzed: The effectiveness of ethanol in hand hygiene, the evidence of ethanol at blood/ tissue levels through hand hygiene in healthcare, and the evidence of toxicity of different blood/tissue ethanol levels and the non-comparability with alcoholic consumption and industrial exposure.

Results: EBHR are essential for preventing infections caused by non-enveloped viruses, especially in healthcare, nursing homes, food industry and other areas. Propanols are effective against enveloped viruses as opposed to non- enveloped viruses but there are no other alternatives for virucidal hand antisepsis. Long-term ingestion of ethanol in the form of alcoholic beverages can cause tumours. However, lifetime exposure to ethanol from occupational exposure < 500 ppm does not significantly contribute to the cancer risk. Mutagenic effects were observed only at doses within the toxic range in animal studies. While reprotoxicity is linked with abuse of alcoholic beverages, there is no epidemiological evidence for this from EBHR use in healthcare facilities or from products containing ethanol in non-healthcare settings.

Conclusion: The body of evidence shows EBHRs have strong efficacy in killing non-enveloped viruses, whereas 1-propanol and 2-propanol do not kill non-enveloped viruses, that pose significant risk of infection. Ethanol absorbed through the skin during hand hygiene is similar to consumption of beverages with hidden ethanol content (< 0.5% v/v), such as apple juice or kefir. There is no risk of carcinogenicity, mutagenicity or reprotoxicity from repeated use of EBHR. Hence, the WHO Task Force strongly recommend retaining ethanol as an essential constituent in hand rubs for healthcare.

In der ersten Jahresausgabe des Magazins "Hygiene & Magazin" wurde ein Beitrag über die 7. Conference of Applied Hygiene and Microbiology and Virology veröffentlicht. Die nächste CAHMV findet statt am 24.11.+25.11.2022, wieder als Hybrid-Veranstaltung sowohl im „AMERON Hamburg Hotel Speicherstadt“, als auch online.

Background: The Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis worldwide and mainly transmitted via the fecal-oral route or consumption of contaminated food products. Due to the lack of efficient cell culture systems for the propagation of HEV, limited data regarding HEV sensitivity to chemical disinfectants are available. Consequently, preventive and evidence-based hygienic guidelines on HEV disinfection are lacking.

Methods: We used a robust HEV genotype 3 cell culture model which allows quantification of viral infection of quasi-enveloped and naked HEV particles. For HEV genotype 1 infections the primary isolate Sar55 in a faecal suspension was applied. Standardized quantitative suspension tests using end point dilution and large-volume-plating were performed for the determination of virucidal activity of alcohols (1-propanol, 2-propanol, ethanol), WHO disinfectant formulations and five different commercial hand disinfectants against HEV. Iodixanol gradients were conducted to elucidate the influence of ethanol on quasi-enveloped viral particles.

Results: Naked and quasi-enveloped HEV was resistant to alcohols as well as alcohol-based formulations recommended by WHO. Of the tested commercial hand disinfectants only one product displayed a virucidal activity against HEV. This activity could be linked to phosphoric acid as essential ingredient. Finally, we observed that ethanol and possibly non-active alcohol-based disinfectants disrupt the quasi-envelope structure of HEV particles, while leaving the highly transmissible and infectious naked virions intact.

Conclusions: Different alcohols and alcohol-based hand disinfectants were insufficient to eliminate HEV infectivity with the exception of one commercial ethanol-based product including phosphoric acid. These findings have strong implications for the efficient prevention measures to reduce viral transmission in clinical practice.

Lay summary: Hepatitis E virus (HEV) showed a strong stability against alcohols and alcohol-based hand disinfectants. With phosphoric acid one essential substance could be identified to active ethanol in its virucidal activity against HEV, which allows to improve hygiene measures for the prevention of HEV transmissions.

Disinfection measures have become more important as a result of the COVID-19 pandemic in Germany. The increased need for disinfectants at the beginning of the pandemic required temporary legal regulations in order to provide a sufficient quantity of products for the necessary disinfection in the medical sector on the one hand and for the additional demand in the population on the other. For this purpose, the Federal Institute for Drugs and Medical Devices (BfArM) and the Federal Institute for Occupational Safety and Health (BAuA) issued a general ruling, which is explained in more detail in this article. The focus was on measures for hygienic hand disinfection. However, other applications such as surface disinfection in relation to pandemic respiratory diseases are also addressed. The experience gained in ensuring the supply of disinfectants that are effective and safe to use should be used to prepare for further pandemics.

The highest viral loads of the newly emerged Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are detectable in the oral cavity, thus, a potential reduction of infectious virus by nasal sprays could lower transmission. Therefore, the inactivation capacity of nine nasal and oral sprays was evaluated according to EN 14476. One nasal spray based on sodium hypochlorite and an oral spray containing essential oils reduced viral titres between 2 to 3 orders of magnitude. Although clinical data is still sparse, nasal and oral sprays display a more convenient application for elderly people or those who are unable to rinse/gargle.

Human papillomaviruses (HPV) are non-enveloped DNA viruses infecting cutaneous and mucosal squamous epithelia. Sexually transmitted HPV-types that are carcinogenic to humans such as HPV16 can induce cervical and other anogenital cancers. Virus transmission through fomites such as inadequately disinfected gynecological equipment is a further potential transmission route. Since HPV cannot be easily grown in cell culture, polyomavirus SV40 has been used as a surrogate virus when testing the virucidal activity of chemical disinfectants. So far, studies that have compared the virucidal activity of different disinfectants against HPV and SV40 are lacking. Here, we evaluated the susceptibility of HPV16 pseudovirus and SV40 to seven active biocidal substances using quantitative suspension tests. Ethanol, glutaraldehyde (GTA), dodecyldipropylentriamin (DPTA), and ortho-phthalaldehydes (OPA) were able to reduce the infectivity of HPV16 pseudovirus >99.99% after 5 min. In contrast, isopropanol, peracetic acid (PAA), and quaternary ammonium compounds with alkylamines (QAC) only led to a slight or no reduction in infectivity. Concerning SV40, only GTA (60 min contact time), PAA, and OPA had virus-inactivating effects. In conclusion, the virucidal activity of three out of seven disinfectants tested was different for HPV16 pseudovirus and SV40. In this study, SV40 was shown to be a reliable surrogate virus for HPV when testing isopropanol-, GTA-, QAC-, and OPA-based disinfectants.

The current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has created a significant threat to global health. While respiratory aerosols or droplets are considered as the main route of human-to-human transmission, secretions expelled by infected individuals can also contaminate surfaces and objects, potentially creating the risk of fomite-based transmission. Consequently, frequently touched objects such as paper currency and coins have been suspected as potential transmission vehicle. To assess the risk of SARS-CoV-2 transmission by banknotes and coins, we examined the stability of SARS-CoV-2 and bovine coronavirus (BCoV), as surrogate with lower biosafety restrictions, on these different means of payment and developed a touch transfer method to examine transfer efficiency from contaminated surfaces to fingertips. Although we observed prolonged virus stability, our results indicate that transmission of SARS-CoV-2 via contaminated coins and banknotes is unlikely and requires high viral loads and a timely order of specific events.

Besides conventional prevention measures, no-touch technologies based on gaseous systems have been introduced in hospital hygiene for room disinfection. The whole-room disinfectant device Sterisafe^TM Pro, which creates ozone as biocidal agent, was tested for its virucidal efficacy based on the NF T 72-281:2014 AFNOR Standard. All test virus titers were reduced after 150 and 300 minutes of decontamination with mean reduction factors (RF) ranging from 2.63 (murine norovirus) to 3.94 (simian virus 40). These results will help to establish realistic conditions for virus inactivation and assessment of efficacy of ozone technology against non-enveloped and enveloped viruses.

Dieses Buch ist als Standardwerk für die wesentlichen Aspekte der Flächenhygiene in allen Bereichen der Versorgung von Patienten und Heimbewohnern konzipiert. Erkenntnisse aus der internationalen wissenschaftlichen Fachliteratur werden umfassend ausgewertet und dargestellt, Fallbeispiele, Infoboxen und Abbildungen erleichtern deren Lesbarkeit. Zahlreiche Tabellen ermöglichen eine intensivere Beschäftigung mit Einzelergebnissen. Mit einem Fazit am Ende eines jeden Kapitels werden die für die Praxis wesentlichen Erkenntnisse komprimiert zusammengefasst. Ein Team aus insgesamt 11 Autoren befasst sich im ersten Teil des Buches mit der Kontamination von Flächen, den Übertragungswegen, Flächen-assoziierten nosokomialen Infektionen, dem OP-Bereich, der unmittelbaren und erweiterten Patientenumgebung, Stethoskopen, mobilen elektronischen Geräten, der praktischen Durchführung von Reinigung und Desinfektion, dem Schutz der Mitarbeiter bei der Durchführung der Flächendesinfektion, den verschiedenen Tuchspendersystemen sowie der Qualitätssicherung in der Flächenhygiene. Im zweiten Buchteil werden die Prüfmethoden zur Bestimmung der Wirksamkeit, die antimikrobielle Wirkung der häufigsten chemischen Wirkstoffe - einschließlich Kupfer und Photodynamik - sowie Möglichkeiten zur Reduktion des bakteriellen Selektionsdrucks in der Flächendesinfektion beschrieben („Antimicrobial Stewardship“).

Background: The presence of coronaviruses on surfaces in the patient environment is a potential source of indirect transmission. Manual cleaning and disinfection measures do not always achieve sufficient removal of surface contamination. This increases the importance of automated solutions in the context of final disinfection of rooms in the hospital setting. Ozone is a highly effective disinfectant which, combined with high humidity, is an effective agent against respiratory viruses. Current devices allow continuous nebulization for high room humidity as well as ozone production without any consumables.

Aim: In the following study, the effectiveness of a fully automatic room decontamination system based on ozone was tested against bacteriophage Φ6 (phi 6) and bovine coronavirus L9, as surrogate viruses for the pandemic coronavirus SARS-CoV-2.

Methods: For this purpose, various surfaces (ceramic tile, stainless steel surface and furniture board) were soiled with the surrogate viruses and placed at two different levels in a gas-tight test room. After using the automatic decontamination device according to the manufacturer's instructions, the surrogate viruses were recovered from the surfaces and examined by quantitative cultures. Then, reduction factors were calculated.

Findings: The ozone-based room decontamination device achieved virucidal efficacy (reduction factor >4 log10) against both surrogate organisms regardless of the different surfaces and positions confirming a high activity under the used conditions.

Conclusion: Ozone is highly active against SARS-CoV-2 surrogate organisms. Further investigations are necessary for a safe application and efficacy in practice as well as integration into routine processes.

The outbreak of the SARS-Cov-2 pandemic is triggering a global health emergency alert. Until vaccination becomes available, a bundle of effective preventive measures is desperately needed. Recent research is indicating the relevance of aerosols in the spread of SARS-CoV-2. Thus, in this study commercially available antiseptic mouthwashes based on the actives chlorhexidine digluconate (CHX) and octenidine dihydrochloride (OCT) were investigated regarding their efficacy against SARS-CoV-2 using the European Standard 14476. Based on the requirement of EN 14476 in which reduction of at least four decimal logarithms (log₁₀) of viral titer is requested to state efficacy, the OCT-based formulation was found to be effective within a contact time of only 15 sec against SARS-CoV-2. Based on this in vitro-data the OCT-mouthwash thus constitutes an interesting candidate for future clinical studies to prove its effectiveness in a potential prevention of SARS-CoV-2 transmission by aerosols.

Safe measurements to prevent the transmission of (multi-drug-resistant) mycobacteria such as disinfection are essential in healthcare settings. In Europe chemical disinfectants are tested for their tuberculocidal and mycobactericidal efficacy by the internationally accepted test procedure described in EN 14348. However, especially for amine-based disinfectants, invalid results can occur by this procedure due to insufficient neutralization. In this multi-lab study the procedure described in EN 14348 was optimized by a combination of chemical neutralization and membrane filtration in order to obtain a valid and secure method especially for amine-based disinfectants.

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic creates a significant threat to global health. Recent studies suggested the significance of throat and salivary glands as major sites of virus replication and transmission during early coronavirus disease 2019, thus advocating application of oral antiseptics. However, the antiviral efficacy of oral rinsing solutions against SARS-CoV-2 has not been examined. Here, we evaluated the virucidal activity of different available oral rinses against SARS-CoV-2 under conditions mimicking nasopharyngeal secretions. Several formulations with significant SARS-CoV-2 inactivating properties in vitro support the idea that oral rinsing might reduce the viral load of saliva and could thus lower the transmission of SARS-CoV-2.

The Arctic ecosystem, a reservoir of genetic microbial diversity, represents a virtually unlimited source of microorganisms that could interact with human beings. Despite continuous exploration of Arctic habitats and description of their microbial communities, bacterial phenotypes commonly associated with pathogenicity, such as hemolytic activity, have rarely been reported. In this study, samples of snow, fresh and marine water, soil, and sediment from several habitats in the Arctic archipelago of Svalbard were collected during Summer, 2017. Bacterial isolates were obtained after incubation on oligotrophic media at different temperatures and their hemolytic potential was assessed on sheep blood agar plates. Partial (ɑ) or true (β) hemolysis was observed in 32 out of 78 bacterial species. Genes expressing cytolytic compounds, such as hemolysins, likely increase the general fitness of the producing microorganisms and confer a competitive advantage over the availability of nutrients in natural habitats. In environmental species, the nutrient-acquisition function of these compounds presumably precedes their function as toxins for mammalian erythrocytes. However, in the light of global warming, the presence of  hemolytic bacteria in Arctic environments highlights the possible risks associated with these microorganisms in the event of habitat melting/destruction, ecosystem transition, and re-colinization.

Hepatitis B virus (HBV) infection is considered a major public health problem worldwide, and a significant number of reports on nosocomial and occupational outbreaks have been reported. This systematic investigation of HBV stability and susceptibility to different antiseptics revealed that HBV infectivity was very stable, with a half-life of >22 days at 37°C. At 4°C, infectivity was barely reduced for up to 9 months. Different alcohols and commercially available hand antiseptics had a virucidal effect against HBV. We propose that very strict compliance with established hygienic guidelines should be mandatory to avoid and prevent HBV infections.

Introduction: Urinary infections are among the most common nosocomial infections, accounting for 23.2% of them. In 80% of cases, these infections are catheterassociated urinary tract infections (CAUTI). The pathogens attach themselves to the catheter walls within a biofilm. Long-term use of urinary catheters is therefore a risk factor for developing a CAUTI. Changing the catheters more frequently would remove the biofilm, but is unpleasant for the patient and timeconsuming for personnel. Regular rinsing of the catheter can be a useful way to remove the emerging biofilm, and to prevent the creation of biofilm in the first place and potential subsequent blockages of the catheter. However, this is not yet standard clinical practice.

Objectives: The influence of rinsing the catheters should be tested in vitro in order to examine its operating principle. Methods: In a practice-like in vitro test method the catheters were contaminated with Escherichia coli, Proteus mirabilis or methicillinresistant Staphylococcus aureus for 72 hours. Afterwards, the catheters were rinsed with 0.02% Polihexanide (PHMB), 0.9% NaCl or were not treated (positive control) and the viable cell count was determined. The biofilm mass was quantified in a staining assay. In addition, fluorescence microscopy assays were performed in a flow cell to visualize the vitality of the cells after rinsing with PHMB or NaCl.

Results: Rinsing the catheters with Polihexanid singnificantly reduced the cell count (p = 0.012). The reduction factor compared to "nontreatment" was 2.56 ± 0.67 log. In comparison to NaCl, rinsing with Polihexanide results in significantly lower cell counts (p = 0.034), higher reduction rates in biofilm mass and is able to kill off the cells at the surface of the biofilm.

Conclusion: Rinsing the catheters reduces colonization of catheters by microorganisms. Polihexanide-rinsing is more effective compared to rinsing with saline solution. A reduction in biomass of the biofilm was demonstrated both by fluorescence microscopy and via the in vitro-model. Further studies need to investigate wheter the presented results can be transferred into practice and actually lead to a reduction in urinary tract infections.

Disclosure of Interest
F. Brill Grant/Research support from: B. Braun Medical AG, S. Pahl: None Declared, J.-H. Klock Grant/Research support from: B. Braun Medical AG, H. Gabriel Grant/Research support from: B. Braun Medical AG, H. Brill Grant/Research support from: B. Braun Medical AG, J. Hambach Grant/Research support from: B. Braun Medical AG, C. Jänicke Grant/Research support from: B. Braun Medical AG, A. Arndt Employee of: B. Braun Medical AG

Hintergrund
Bei den verschiedenen Urostomien wie dem Ileumconduit und der Ureterhautfistel besteht ein hohes Infektionsrisiko für die Nieren und das harnableitende System des Patienten. Deshalb ist das Vermeiden des Aufsteigens von Bakterien im künstlichen Abfluss (Splintkatheter) durch z. B. kontaminierten Harn wichtigstes Ziel der hygienischen Maßnahmen. Es sollte in vitro nachgewiesen werden, wie schnell klinisch relevante Prüfbakterien diese Splintkatheter besiedeln können.

Methode
Es wurde die Wanderungsgeschwindigkeit von Bakterien in einem handelsüblichen Splintkatheter in einem praxisnahen In-vitro-Modell untersucht. Hierzu wurde ein Vorratsgefäß mit Splintkathetern mit einem zweiten Vorratsgefäß verbunden, in dem eine Bakteriensuspension der Prüfbakterien Escherichia coli, Proteus mirabilis und Staphylococcus aureus in künstlichem Harn vorgelegt wurde. Die beiden Vorratsgefäße wurden bei 36 °C bis zu 72 h inkubiert. Die Keimzahl in den Splintkathetern wurde nach 24 h, 48 h und 72 h bestimmt, um die Besiedlungsstrecke nachzuweisen.

Ergebnisse
Die durchschnittliche Wanderungsgeschwindigkeit lag bei 0,63 cm/h für E. coli, 0,80 cm/h für S. aureus und 0,94 cm/h für P. mirabilis. Dies ergibt eine gemittelte Besiedlungsstrecke von 80 cm in ca. 3 Tagen.

Schlussfolgerungen
Aus den Ergebnissen im In-vitro-Modell lässt sich eine hohe Wanderungsgeschwindigkeit der Bakterien ableiten. In vivo würde es bedeuten, dass innerhalb der üblichen Liegedauer der Splintkatheter beim Urostoma von 10–14 Tagen vollständig besiedelt wird.

Schlüsselwörter
Urostoma Splint Bakterien Hygiene Bakterienwanderung


Abstract

Background
A urostomy with an ileum conduit or a skin fistula leads to a high infection risk for the kidneys and the ureter of the patient. Therefore, the prevention of retrograde colonization of the artificial drain (splint) with e. g. contaminated urine is the most important objective of infection prevention measurements. We performed an in vitro experiment to determine the migration speed of clinically relevant bacteria in a commercially available splint catheter system.

Methods
The migration speed of bacteria in commonly used splint catheters was determined in a practice-like in vitro model. Two storage vessels were connected with splints. The second vessel contained a bacterial suspension of the test bacteria Escherichia coli, Proteus mirabilis, and Staphylococcus aureus in artificial urine. The two vessels were incubated at 36 °C for 24–72 h. The microbial count in the catheters was determined after each experiment to investigate the migration distance.

Results
The average migration speed was 0.63 cm/h for E. coli, 0.80 cm/h for S. aureus, and 0.94 cm/h for P. aeruginosa. This results in a colonization distance of approximately 80 cm in 3 days.

Conclusion
If the system, e. g., the stoma pouch is contaminated, it can be expected that during the common application time of a splint of 10–14 days, the complete splint will be contaminated due to the high bacteria migration speed. Consequently there is a high infection risk for kidneys and ureters. A return stop feature in the stoma pouch should minimize this risk. However, it is of upmost importance to not applying the splint through the return stop to prevent any contact with potentially contaminated urine.

Keywords
Urostomy Splint Bacteria Hygiene Bacteria migration speed

In May 2012, Branch-Elliman et al reported an outbreak of hepatitis C virus (HCV) infections due to contamination of multidose medication vials.1 The New York City Department of Health and Mental Hygiene was informed of a cluster of 4 patients treated at an outpatient gastroenterology center who developed acute HCV infection. A detailed investigation identified a total of 12 clinic-associated HCV transmissions within a period of 8 days, which were traced back to unsafe handling of multidose medication vials and possible reuse of contaminated needles during anesthetic procedures.

Hepatitis C virus (HCV) is transmitted primarily through percutaneous exposure to contaminated blood especially in healthcare settings and among people who inject drugs. The environmental stability of HCV has been extrapolated from studies with the bovine viral diarrhoea virus or was so far only addressed with HCV genotype 2a viruses. The aim of this study was to compare the environmental and thermostability of all so far known seven HCV genotypes in vitro and in vivo. Incubation experiments at room temperature revealed that all HCV genotypes showed similar environmental stabilities in suspension with viral infectivity detectable for up to 28 days. The risk of HCV infection may not accurately be reflected by determination of HCV RNA levels. However, viral stability and transmission risks assessed from in vitro experiments correlated with viral infectivity in transgenic mice containing human liver xenografts. A reduced viral stability for up to 2 days was observed at 37 °C with comparable decays for all HCV genotypes confirmed by thermodynamic analysis. These results demonstrate that different HCV genotypes possess comparable stability in the environment and that noninfectious particles after incubation in vitro do not cause infection in an HCV in vivo model. These findings are important for estimation of HCV cross-transmission in the environment and indicate that different HCV genotypes do not display an altered stability or resistance at certain temperatures.

Studiendesign: In einer hygienisch-mikrobiologischen Laborstudie wurde untersucht, ob Septen-Systeme von Infusionsflaschen mit einem alkoholischen Hautantiseptikum desinfizierbar sind und ob es diesbezüglich Unterschiede zwischen verschieden konstruierten Systemen gibt. Die Untersuchung sollte zeigen, welches hygienische Risiko bei der Wiederverwendung solcher Systeme entsteht, die herstellerseitig nur für den einmaligen Gebrauch vorgesehen sind.

Methodik: Jeweils 10 Septen-Systeme (Kabipac®, Ecoflac® plus, Sintetica-Bioren) wurden mit 2,5 x 108 KBE des Hautbakteriums Staphylococcus aureus und des Luftkeims Kucuria rhizophila kontaminiert. 9 Systeme wurden nach Antrocknung der Bakterien mit einem alkoholischen Hautantiseptikum wischdesinfiziert. 1 System diente als Wachstumskontrolle. Anschließend wurde die bakterielle Restbelastung mittels Tupferprobe bestimmt.

Ergebnisse: Nach der Desinfektion von Ecoflac® plus zeigten 7 von 9 Tupferproben kein Wachstum. Von einem Septen-System wurde ein Bakterium und von einem 37 KBE isoliert. Bei Kabipac® waren 7 Tupferproben keimfrei; in 2 Fällen wurden hohe Keimzahlen zurückgewonnen. Die Tupferabstriche des Septen-Systems von Sintetica-Bioren zeigten in 6 von 9 Fällen hohe Keimzahlen. 2 Tupferproben zeigten kein Wachstum.

Schlussfolgerungen: Grundsätzlich ist eine effektive Desinfektion von Infusionsflaschen-Septen-Systemen mit einem alkoholischen Hautantiseptikum möglich. Jedoch sind verschieden konstruierte Systeme, unterschiedlich leicht hygienisch aufzubereiten. Je einfacher das Desinfektionsmittel bei einer Wischdesinfektion die Oberflächen der Systeme erreicht, desto höher ist die Wirkung. Deshalb sind solche Systeme für den Einsatz in der Praxis zu bevorzugen, bei denen die Oberflächen einfach zu erreichen und die möglichst eben ausgeführt sind.

Background: For over 100 years, airborne disinfection processes have been employed as an alternative to complement manual surface disinfection methods involving spraying or wiping. The advantage of these airborne methods is that they can potentially reach all of the surfaces in a room. Recently, developments have seen various active substances and techniques added to the mix, including methods that use hydrogen peroxide, peracetic acid, or ozone. Just like conventional disinfection procedures, all of these methods need to be tested for efficacy. However, the established methods for testing chemical surface disinfectants do not adequately reflect how these products are being used in practice.
Generally, these kinds of processes are used as complements to “standard” surface cleaning and disinfection, and they cannot replace these methods. They may be used in areas such as isolation rooms and operating theatres, as a useful addition to the routine disinfection process.

Aims: We aimed to develop a method to assess the virucidal performance of domestic laundry in a lab-scale washing machine (Rotawash) based on EN 17658.

Methods and Results: For method development, virus recovery was investigated after drying on cotton carriers for three test viruses (MNV, MVA and BCoV), followed by washing simulations in flasks and Rotawash. MNV and MVA demonstrated sufficient recovery from carriers after drying and washing (up to 40°C and 60 min). BCoV exhibited lower recovery, indicating less relevance as a test virus. Rotawash efficacy tests conducted with MNV, a resistant, non-enveloped virus, showed limited efficacy of a bleach-free detergent, aligning with results from a domestic washing machine. Rotawash washes achieved higher reductions in infectious virus titers than suspension tests, indicating the role of washing mechanics in virus removal.

Conclusions: This study established a practical method to test the virucidal efficacy of laundry detergents in Rotawash, simulating domestic washing.

Die Testung und Listung von Desinfektionsmitteln für den humanmedizinischen Bereich wurde in Deutschland ab 1959 zunächst durch die Deutsche Gesellschaft für Hygiene und Mikrobiologie (DGHM) und seit 2003 durch den Verbund für Angewandte Hygiene (VAH) abgesichert. Die Prüfmethoden und Anforderungen, die zu einer Zertifizierung und Listung durch den VAH führen, sind veröffentlicht, werden kontinuierlich überprüft und bei Bedarf neuen Erfordernissen angepasst.

Introduction & Aim: Insufficient disinfection of frequently touched surfaces in healthcare facilities is an important risk factor in the spreading of nosocomial pathogens. For a disinfectant to be registered as a biocidal product, it must pass several phase 1 and 2 efficacy tests, which are very standardized but do not reflect the reality during the actual use of the product. To be able to test disinfectants under real life conditions in the lab, the first phase 3 step 1 test was developed in this study.

Download the poster for further details (Material & Methods, Results, Conclusions)

Introduction & Aim: The raising challenge of Multi-Drug-Resistant Organisms (MDRO) in the clinical field causes questions to what extend surface disinfectants present with reduced activity. Another scientific question is if the susceptibility of laboratory strains mentioned in the European Standards (EN) are representing clinically isolated strains.

Download the poster for further details (Material & Methods, Results, Conclusions)

Background: The use of automatic UV-C disinfection devices has increased in recent years to improve cleaning performance in hospitals. Since laboratory tests allow no direct conclusions about effectiveness in a hospital, we established a field test for efficacy assessment of UV-C in comparison to manual disinfection under realistic conditions.

Methods: Frequent sampling of surfaces with close contact to high risk patients were taken before and after disinfection using swab technique to obtain representative data samples for disinfected and non-disinfected surfaces. Subsequently, the log reduction values (LRV) and the proportion of disinfection success were evaluated for UV-C radiation and full compliant manual disinfection using alcohol based wipes.

Results: Mean contamination was reduced from 23.3 to 1.98 cfu/cm² (LRV 0.9) and 29.7 to 0.26 cfu/cm² (LRV 1.2) for UV-C and manual disinfection, respectively. UV-C disinfection achieved 75.5 % successful disinfected surfaces, whereas manual disinfection showed 97.2 %.

Conclusions: Full compliant manual disinfection showed slightly greater LRV and disinfection success than automatic UV-C disinfection. In comparison to manual disinfection success in reality, operator-independent UV-C disinfection still enables the potential to improve disinfection performance in addition to manual disinfection.

In the clinical setting, surface disinfection is an important measure to reduce the risk of cross-transmission of microorganisms and the risk of nosocomial infections. Standardized methods can be used to evaluate said disinfection procedures, as well as the effectiveness of the active ingredients used for disinfection. However, despite standardization, the results of such methodologies are still determined by several factors and incorrect results may lead to invalid assumptions about the effectiveness of a disinfectant, posing significant health risks for patients and health personnel. The objective of this study was to evaluate several determinants for the recovery of Pseudomonas aeruginosa and other test organisms to establish their influence on the results of standardized disinfection methodologies and to find Gram-negative strains that could be used as suitable replacements of P. aeruginosa. The effects of inoculum application, drying times and temperatures as well as surface material on the survival and recovery of the test organisms were evaluated using Student-T test, one-way ANOVA and Tuckey's multiple comparison tests. Our results show that temperature and length of drying as well as application method and the material of germ carriers have significant effects on the recovery of P. aeruginosa cells and therefore influence the outcome of the methodologies used. This study also presents data showing that P. aeruginosa could be replaced with the Gram-negative species Acinetobacter baumannii, a test organism already in many standardized methodologies, which responds better under the same circumstances and has a behavior similar to that of P. aeruginosa in disinfectant efficacy tests.

Background: The efficacy of ultraviolet C (UV–C) radiation against a broad spectrum of micro-organisms has been demonstrated in several studies, but differences in the specific doses and the extent of microbial reduction were found. Furthermore, the conditions of laboratory tests differ greatly from reality, such that efficacy achieved in tests may not necessarily be assumed in reality. Consequently, it is important to investigate the effectiveness of UV-C in representative field trials. The aim was therefore to develop and establish a field test to evaluate automatic UV-C in comparison to manual disinfection.

Methods: Before and after disinfection, samples were repeatedly collected from naturally highly contaminated surfaces using the swab technique to obtain representative data sets for disinfected and non-disinfected surfaces. Subsequently, the log reduction values (LRV) and the disinfection success were evaluated for UV-C radiation and full compliant manual disinfection using alcohol-based wipes.

Results: Surfaces that are naturally contaminated with bacteria on a regular and nearly uniform basis have been identified as particularly suitable for field testing. Mean contamination was reduced from 23.3 to 1.98 cfu/cm2 (LRV 0.9) and 29.7 to 0.26 cfu/cm2 (LRV 1.2) for UV-C and manual disinfection, respectively. UV-C disinfection achieved 75.5% successful disinfected surfaces, whereas manual disinfection showed 98.1%.

Conclusions: Full compliant manual disinfection showed slightly higher LRVs and disinfection success than automatic UV-C disinfection. Successful, operator-independent UV-C disinfection still has the potential to improve disinfection performance in addition to manual disinfection.

Background: The methods currently used in Europe and North America to evaluate the bactericidal efficacy of hand hygiene products have some limitations, e.g., in the selection of test organisms or the method of contamination, and none of the methods allows prediction of actual clinical efficacy. WHO has therefore proposed to develop methods that better reflect typical clinical reality.

Methods: In a first experiment, we investigated two contamination methods (immersion according to EN 1500 and low-volume according to ASTM E2755) with the EN 1500 test organism Escherichia coli and using 60% v/v iso-propanol. The second experiment was for comparison of the two contamination methods with Enterococcus faecalis. Finally, the two test organisms were compared using the low-volume contamination method. Data within each experiment was statistically compared using the Wilcoxon test for paired samples and data from all experiments were combined and fit to linear mixed effects models.

Results: Mixed-effects analysis confirmed that the test organism and contamination method both impacted the pre-values and all three of these were factors that influenced log10 reductions. Higher pre-values resulted in significantly higher log10 reductions, immersion contributed to significantly higher log10 reductions, and E. coli affected significantly lower log10 reductions.

Conclusion: An efficacy evaluation against E. faecalis with a low-volume contamination method could be considered as an alternative to the EN 1500 standard. This could help improve the clinical relevance of the test method with including a Gram-positive organism and reducing soil load which allows a product application closer to reality.

Keywords: EN 1500; Enterococcus faecalis; Escherichia coli; alcohol-based hand rubs; bactericidal efficacy; contamination method.

Background: Adenoviruses belong to the stable nonenveloped viruses playing an important role in healthcare-associated infections mainly causing respiratory infections and epidemic keratoconjunctivitis. Hand disinfection with alcoholic preparations is therefore one of the most important measures to prevent such viral infections in hospitals and other medical settings.

Methods: The inactivation of adenovirus type 5 by ethanol, 1- and 2-propanol, and 2 commercially available hand disinfectants was examined at different concentrations, temperatures, and pH-values.

Results: For ethanol and 1-propanol the maximum virus-inactivating properties after 30 seconds exposure were found at a concentration of 60%-70% and 50%-60%, respectively, whereas with 2-propanol no activity was observed. The virucidal activity of all alcohols and the 2 hand disinfectants examined was increased when raising the temperature from 20°C to 25°C. By increasing the pH value to 9, a strong improvement of the activity of ethanol, 1-propanol and 1 hand disinfectant was observed, whereas pH lowering resulted in decrease of activity.

Conclusions: These results demonstrate the importance of physical parameters in the inactivation of adenoviruses by alcohols and will help to improve measures to reduce adenovirus transmission in healthcare settings.

Keywords: Adenovirus type 5; Alcohols; Temperature; Virucidal activity; pH-value.

Background: Long-term use of urethral catheters is associated with high risk of urinary tract infection (UTI) and blockage. Microbial biofilms are a common cause of catheter blockage, reducing their lifetime and significantly increasing morbidity of UTIs. A 0.02% polyhexanide irrigation solution developed for routine mechanical rinsing shows potential for bacterial decolonization of urethral catheters and has the potential to reduce or prevent biofilm formation.

Methods: Using an in vitro assay with standard market-leading types of catheters artificially contaminated with clinically relevant bacteria, assays were carried out to evaluate the biofilm reduction and prevention potential of a 0.02% polyhexanide solution versus no intervention (standard approach) and irrigation with saline solution (NaCl 0.9%). The efficiency of decolonization was measured through microbial plate count and membrane filtration.

Results: Irrigation using a 0.02% polyhexanide solution is suitable for the decolonization of a variety of transurethral catheters. The effect observed is significant compared to irrigation with 0.9% saline solution (p = 0.002) or no treatment (p = 0.011). No significant difference was found between irrigation with 0.9% saline solution and no treatment (p = 0.74).

Conclusions: A 0.02% polyhexanide solution is able to reduce bacterial biofilm from catheters artificially contaminated with clinically relevant bacteria in vitro. The data shows a reduction of the viability of thick bacterial biofilms in a variety of commercially available urinary catheters made from silicone, latex-free silicone, hydrogel-coated silicone and PVC. Further research is required to evaluate the long-term tolerability and efficacy of polyhexanide in clinical practice.

Legionellen sind eine weltweit verbreitete im Wasser lebende Bakteriengattung. Seitdem die gezielte Suche nach Legionellen 2011 in der Trinkwasserverordnung (TrinkwV) aufgenommen wurden, gab es bisher mehrere Änderungsverordnungen. Seit der Änderungsverordnung 2018 sinderstmals Trinkwasserlabore verpflichtet, eine Überschreitung des technischen Maßnahmenwertes für Legionel- len (>100 KBE/100 ml) an das örtliche Gesundheitsamt zu melden. IndieserArbeitwurdenUntersuchungs- ergebnisse nach TrinkwV auf Legionel- len einer norddeutschen Trinkwasser- untersuchungsstelle von 2012 und 2016 retrospektiv ausgewertet. Ziel der Studie war es, zu untersuchen, inwiefern die Novellierung der Trinkwasserverordnung dazu beigetragen hat, die Anzahl an Überschreitungen des Techni- schen Maßnahmenwertes (TMW) zu verringern.

Biofilm formation is a strategy of many bacterial species to adapt to a variety of stresses and has become a part of infections, contaminations, or beneficial interactions. In this study, we demonstrate that profound physiological changes permit Bacillus cereus to switch from a floating to a sessile lifestyle, to undergo further maturation of the biofilm and to differentiate into the offensive or defensive features. We report that floating and biofilm cells are populations that differentiate metabolically, with members of each subpopulation developing different branches of certain metabolic pathways. Secondly, biofilm populations rearrange nucleotides, sugars, amino acids, and energy metabolism. Thirdly, this metabolic rearrangement coexists with: the synthesis of the extracellular matrix, sporulation, reinforcement of the cell wall, activation of the ROS detoxification machinery and production of secondary metabolites. This strategy contributes to defend biofilm cells from competitors. However, floating cells maintain a fermentative metabolic status that ensures a higher aggressiveness against hosts, evidenced by the production of toxins. The maintenance of the two distinct subpopulations is an effective strategy to face different environmental conditions found in the life styles of B. cereus.

Desinfektionsmittel, die im Krankenhaus und in der ärztlichen Praxis zum Einsatz kommen sollen, müssen abhängig vom Anwendungsgebiet neben einer bakteriziden und levuroziden Wirksamkeit, auch gegen alle oder bestimmte Viren als Infektionserreger wirksam sein. Relevante virale Infektionserreger stellen beispielsweise Noroviren, Influenza A-Viren oder Herpes simplex-Viren dar. Doch erst vor einigen Jahren wurde intensiv damit begonnen, praxisnahe Prüfungen zur Viruswirksamkeit zu entwickeln. Aktuell wird weiterhin die Mehrzahl der viruziden Wirksamkeitsauslobungen lediglich auf Basis von Suspensionsversuchen getroffen, was den tatsächlichen Anwendungsfall der Produkte jedoch nur unzureichend nachstellt. Im Folgenden wird der Stand der Entwicklung praxisnaher Tests in der Virologie zusammengefasst.

Die Auslobung der Viruzidie von Tüchern zur Flächendesinfektion basiert momentan ausschließlich auf einem Suspensionsversuch und einem Carrierversuch ohne Mechanik. Für die Bakterien und Pilze existiert bereits ein praxisnaher Test mit Mechanik (4-Felder-Test), der in der Virusprüfung bislang noch nicht vorhanden ist. Ziel muss es daher sein, auch für Viren diesen 4-Felder-Test zu entwickeln. Insbesondere müssen die Prüfviren für diese praxisnahe Methode noch ausgewählt werden, wobei darauf zu achten ist, dass diese das gesamte Spektrum der relevanten Erreger nosokomialer Infektionen abdecken. Erste Untersuchungen zeigen, dass eine solche praxisnahe Prüfmethode für Tücher auch mit Viren entwickelt werden kann, um dann eine entsprechende Viruzidie der Tücher ausloben zu können.

No Abstract

Surface disinfectants are part of broader preventive strategies preventing the transmission of bacteria, fungi and viruses in medical institutions. To evaluate their virucidal efficacy, these products must be tested with appropriate model viruses with different physico-chemical properties under conditions representing practical application in hospitals.

The aim of this study was to evaluate a quantitative carrier assay. Furthermore, different putative model viruses like adenovirus type 5 (AdV-5) and different animal parvoviruses were evaluated with respect to their tenacity and practicability in laboratory handling. To evaluate the robustness of the method, some of the viruses were tested in parallel in different laboratories in a multi-center study. Different biocides, which are common active ingredients of surface disinfectants, were used in the test. After drying on stainless steel discs as the carrier, model viruses were exposed to different concentrations of three alcohols, peracetic acid (PAA) or glutaraldehyde (GDA), with a fixed exposure time of 5 minutes. Residual virus was determined after treatment by endpoint titration.

All parvoviruses exhibited a similar stability with respect to GDA, while AdV-5 was more susceptible. For PAA, the porcine parvovirus was more sensitive than the other parvoviruses, and again, AdV-5 presented a higher susceptibility than the parvoviruses. All parvoviruses were resistant to alcohols, while AdV-5 was only stable when treated with 2-propanol. The analysis of the results of the multi-center study showed a high reproducibility of this test system.

In conclusion, two viruses with different physico-chemical properties can be recommended as appropriate model viruses for the evaluation of the virucidal efficacy of surface disinfectants: AdV-5, which has a high clinical impact, and murine parvovirus (MVM) with the highest practicability among the parvoviruses tested.

Urologe 2012 51:403-408
DOI 10.1007/s00120-012-2807-8
Online publiziert: 15. Februar 2012
© Springer-Verlag 2012

To investigate the effectiveness of antimicrobial agents against wound infections, experiments using either 2D cultures with planktonic microorganisms or animal infection models are frequently carried out. However, the transferability of the results to human skin is limited by the lack of complexity of the 2D models or by the poor translation of the results from animal models. Hence, there is a need for wound infection models capable of assessing antimicrobial agents. In this study, an easily standardized wound infection model was established. This model consists of a mechanically wounded human skin model on a collagen matrix infected with various clinically relevant bacteria. Infection of the model led to recognition of the pathogens and induction of an inflammatory response. The untreated infection spread over time, causing significant tissue damage. By applying an antimicrobial-releasing wound dressing, the bacterial load could be reduced and the success of the treatment could be further measured by a decrease in the inflammatory reaction. In conclusion, this wound infection model can be used to evaluate new antimicrobial therapeutics as well as to study host-pathogen interactions.

Biofilms are a major problem in hard-to-heal wounds. Moreover, they are composed of different species and are often tolerant to antimicrobial agents. At the same time, interspecific synergy and/or competition occurs when some bacterial species clash. For this reason, the tolerance of two dual-species wound biofilm models of Pseudomonas aeruginosa and Staphylococcus aureus or Enterococcus faecium against antimicrobials and antimicrobial dressings were analyzed quantitatively and by confocal laser scanning microscopy (CLSM). The results were compared to findings with planktonic bacteria. Octenidine-dihydrochloride/phenoxyethanol and polyhexamethylene biguanide (PHMB) irrigation solutions showed a significant, albeit delayed reduction in biofilm bacteria, while the PHMB dressing was not able to induce this effect. However, the cadexomer-iodine dressing caused a sustained reduction in and killed almost all bacteria down to 102 cfu/mL within 6 days compared to the control (1010 cfu/mL). By means of CLSM in untreated human biofilm models, it became evident that P. aeruginosa dominates over E. faecium and S. aureus. Additionally, P. aeruginosa appeared as a vast layer at the bottom of the samples, while S. aureus formed grape-like clusters. In the second model, the distribution was even clearer. Only a few E. faecium were visible, in contrast to the vast layer of P. aeruginosa. It seems that the different species avoid each other and seek their respective niches. These mixed-species biofilm models showed that efficacy and tolerance to antimicrobial substances are nearly species-independent. Their frequent application appears to be important. The bacterial wound biofilm remains a challenge in treatment and requires new, combined therapy options.

Hintergrund: Der Wund-pH-Wert von akuten und chronischen Wunden unterscheidet sich deutlich und verändert sich im Laufe der Wundheilung. Bisher bleiben die klinisch relevanten, unterschiedlichen Wund-pHWerte bei der Prüfung der in-vitro-Wirksamkeit von antimikrobiellen Wundtherapeutika unberücksichtigt. In der vorliegenden Studie sollte untersucht werden, ob die in den Wundauflagen verwendeten antimikrobiellen Substanzen – Silberionen und Polihexanid (PHMB) – eine pH-abhängige antimikrobielle Wirkung aufweisen.

Methode: Im Agardiffusionstest wurde an ausgewählten Wundauflagen untersucht, ob die in den Wundauflagen verwendeten und freigesetzten, antimikrobiellen Wirkstoffe – Silberionen und Polihexanid (PHMB) – eine pH-abhängige antimikrobielle Wirkung haben. Prüforganismen waren Staphylococcus aureus, Methicillin-resistenter Staphylococus aureus (MRSA), Enterococcus faecium und Pseudomonas aeruginosa. Geprüft wurden Biatain Ag (Schaumverband, Coloplast GmbH, Hamburg), Seasorb Ag (Alginatverband, Coloplast GmbH, Hamburg) und Suprasorb X+PHMB (Hydrobalance Wundverband, Lohmann & Rauscher GmbH & Co. KG, Neuwied).

Ergebnisse: Die PHMB-haltige Wundauflage hatte im sauren pH-Bereich (pH 5,5) gegenüber allen Testkeimen keine Wirkung (Hemmhof 0 mm). Bei pH 6,0 zeigte sich keine Wirkung gegenüber MRSA (Hemmhof 0,3 mm), E. faecium und P. aeruginosa (Hemmhof jeweils 0 mm), jedoch eine Hemmwirkung gegenüber S. aureus (Hemmhof 1,8 mm). Im neutralen (pH 7,0) und alkalischen Bereich (pH 8,0) besaß diese Wundauflage mit Ausnahme von P. aeruginosa eine bakteriostatische Wirkung (Hemmhof 1,0–6,8 mm). Bei pH 9,0 wurde für alle Prüforganismen eine bakteriostatische Wirkung nachgewiesen (Hemmhof 1,5–9,3 mm). Die Silberionenfreisetzenden Wundauflagen zeigten dagegen im getesteten pH-Bereich (5,5 bis 9,0) eine gleichmäßig gute bakterio-statische Wirksamkeit (Hemmhof 0,8–5,5 mm). Für den Schaumverband wurde im Vergleich zum Alginatverband eine stärkere Wirksamkeit nachgewiesen.

Schlussfolgerung: Aus diesen Ergebnissen können noch keine endgültigen Empfehlungen für die Praxis getroffen werden. Unsere Ergebnisse machen jedoch deutlich, dass der pH-Wert der Wunde einen Einfluss auf die antimikrobielle Wirksamkeit von antimikrobiell ausgerüsteten Wundauflagen hat.

Chemikalienrückstände von Reinigungs- und Desinfektionsmittel nach der manuellen Aufbereitung dentaler Übertragungsinstrumente stellen eine besondere Herausforderung bei der Kontrolle des Reinigungserfolges dar. Diese periodische Kontrolle ist ein elementarer Bestandteil der validierten Aufbereitung und erfolgt durch die Bestimmung des Restproteingehalts mittels OPA-Methode. Matrixeffekte zwischen Chemikalienrückständen und dem OPA-Reagenz können die Proteinquantifizierung beeinflussen und zu massiv falsch-positiven Ergebnissen führen. Die vorliegende Arbeit zeigt eine neuartige Methode zur Eliminierung dieser Matrixeffekte. Durch Zugabe einer Zelltrümmersuspension zum OPA-Messansatz konnte eine Eliminierung der Matrixeffekte um 74 – 100 % erreicht werden.

Background
Long-term use of indwelling urethral catheters is associated with high risk of urinary tract infection (UTI) and blockage, which may in turn cause significant morbidity and reduce the life of the catheter. A 0.02% polyhexanide irrigation solution has been developed for routine mechanical rinsing together with bacterial decolonization of suprapubic and indwelling urethral catheters.

Methods
Using a practice-like in vitro assay and standard silicon catheters, artificially contaminated with clinically relevant bacteria, experiments were carried out to evaluate the bacterial decolonization potential of polyhexanide vs. 1) no intervention (standard approach) and 2) irrigation with a saline (NaCl 0.9%) solution. Swabbing and irrigation was used to extract the bacteria.

Results
Irrigation with polyhexanide reduced the microbial population vs. the control catheters by a factor of 1.64 log10 (swab extraction) and by a factor of 2.56 log10 (membrane filtration). The difference in mean microbial counts between the two groups (0.90) was statistically significant in favor of polyhexanide when the liquid extraction method was used (p = 0.034). The difference between the two groups using the swab extraction method did not reach statistical significance.

Conclusions
The saline and polyhexanide solutions are able to reduce bacterial load of catheters, which shows a combined mechanical and antimicrobial effect. Further research is required to evaluate the long-term tolerability and efficacy of polyhexanide in clinical practice.

Biofilme (wörtlich = lebende dünne Schicht) sind Lebensgemeinschaften unterschiedlicher Mikroorganismen. Diese sezernieren extrazelluläre polymere Substanzen (vorwiegend Zuckermoleküle), die die dreidimensionale Matrix des Biofilms bilden (3). Sofern ausreichend Nährstoffe, Wasser sowie eine Grenzfläche vorhanden sind, bilden sich Biofilme. Chronische Wunden erfüllen durch ihr feucht-warmes Milieu, einem ausreichenden Nährstoffangebot sowie dem Wundgrund als Grenzfläche gute Voraussetzungen für die Biofilmbildung. Deshalb sind in circa 60 % der chronischen Wunden Biofilmstrukturen nachweisbar (5). Der Wundgrund ist jedoch keine ideale Grenzfläche, da er zum Beispiel Exsudat sezerniert sowie durch Muskel- und Hautkontraktionen in Bewegung ist. Daher bilden sich im Vergleich zu festen Grenzflächen wie Kunststoffen in Wunden üblicherweise keine besonders schwer zu entfernenden Biofilme.

Mikroorganismen leben vorzugsweise in einem Biofilm, weil sie (6):
- vor Austrocknung und Scherkräften geschützt sind,
- eine bis zu 1000-fach geringere Sensibilität gegenüber antimikrobiellen Wirkstoffen ausbilden können,
- eine verbesserte Nährstoffversorgung haben,
- neue ökologische Mikronischen vorfinden zum Beispiel sauerstoffreiche und -arme Bereiche.

In der klinischen Praxis kann ein Biofilm in der Regel nur durch erfahrene Kliniker diagnostiziert werden. Biofilme stellen sich als schleimige Beläge dar. Grundsätzlich gilt, dass sie wie andere Wundbeläge die Wundheilung stören können, da sie eine chronisch-entzündlichen Reaktion stimulieren (4). Daher ist im Rahmen des Wundmanagements eine Entfernung von Biofilmen anzustreben. Hierfür gibt es verschiedene Möglichkeiten, wobei der Goldstandard die mechanische Entfernung ist. Dies ist in Wunden meist optimal möglich, da sie gut zugänglich sind. Dabei sind Maßnahmen, die zur Entfernung von „Wundbelägen“ wirksam sind, auch für Biofilme effektiv:
- Spülen mit Kochsalz-, Ringer-Lösung oder sterilem Wasser,
- Spülen mit tensidhaltigen, antimikrobiellen Wundspüllösungen,
- mechanisches Wischen in der Regel in Kombination mit einer der genannten Lösungen,
- „scharfe“ chirurgische Maßnahmen oder zum Beispiel Ultraschall-Debridement.
Optimal ist es, Biofilmen und Wundbelägen vorzubeugen durch:
- Spülen mit Kochsalz-, Ringer-Lösung oder sterilem Wasser,
- Spülen mit tensidhaltigen, antimikrobiellen Wundspüllösungen,
- mechanisches Wischen in der Regel in Kombination mit einer der genannten Lösungen.

Die Besonderheit bei der Prävention von Biofilmen ist, dass ein antimikrobieller Wirkstoff in der Wunde der Bildung von Biofilmen vorbeugen kann. Damit kann auch das Risiko für eine Wundinfektion vermindert werden, welches grundsätzlich bei vorhandenem Biofilm aufgrund der hohen Anzahl von Mikroorganismen hoch ist.
Abbildung 1 verdeutlicht, wie der antiseptische Wirkstoff Polyhexanid (PHMB) auf einen Biofilm wirkt (2). Die rot dargestellten toten Zellen zeigen, dass ausschließlich die oberen Schichten des Biofilms erreicht werden, daher kommt der Biofilmprävention eine besondere Bedeutung bei. Hierbei gilt, dass alle Maßnahmen, die zum mikro-biologischen Wundmanagement hilfreich sind, auch gegen Biofilme funktionieren. Abb. 1: Fluoreszenzmikroskopische Aufnahme zur Wirkung von 0,9 % Kochsalzlösung (oben) bzw. 0,02 % Polyhexanid (unten) auf einen künstlichen Biofilm. Durch Polyhexanid werden die Zellen an der Oberfläche des Biofilms abgetötet (grün = lebende Zellen, rot = tote Zellen).

Zusammenfassend kann festgehalten werden, dass die Reinigung und Infektionsprävention chronischer Wunden essentiell ist. Moderne Reinigung und Infektionspräven¬tion beinhaltet und beherrscht damit die Herausforderung Biofilm. Da Biofilme in chronischen Wunden nicht zu verhindern sind, ist ein erfolgreicher Wundmanager ein Biofilmmanager.

Literatur
1. Brill F, Koca A, Böttrich JG. Behandlung von Wunden mit Prontosan-Wundspüllösung zur Entfernung von Biofilmen und anderen Wundbelägen. Hospitalis 2007;77(7/8):230-231.
2. Eberlein T, Fendler H, Hoffmann M. Ulcus cruris venosum – Prontosan-Lösung oder Standardbehandlung? Die Schwester Der Pfleger 2006;45(9/06):2-4.
3. Flemming HC, Wingender J. Biofilme – die bevorzugte Lebensform der Bakterien. Biologie in unserer Zeit 2001;31(3):169-179.
4. Flemming HC, Wingender J. Was Biofilme zusammenhält. Chemie in unserer Zeit 2002;36(1):30-42.
5. James GA, Swogger E, Wolcott R, et al. Biofilms in chronic wounds. Wound Repair Regen 2008;16(1):37-44.
6. Phillips PL, Wolcott RD, Fletcher J et al. Biofilms Made Easy. Wounds International 2010;1(3).

OBJECTIVE:
Acute traumatic wounds are contaminated with bacteria and therefore an infection risk. Antiseptic wound irrigation before surgical intervention is routinely performed for contaminated wounds. However, a broad variety of different irrigation solutions are in use. The aim of this retrospective, non-randomised, controlled longitudinal cohort study was to assess the preventive effect of four different irrigation solutions before surgical treatment, on wound infection in traumatic soft tissue wounds.

METHOD:
Over a period of three decades, the prophylactic application of wound irrigation was studied in patients with contaminated traumatic wounds requiring surgical treatment, with or without primary wound closure. The main outcome measure was development of wound infection. From 1974-1983, either 0.04 % polihexanide (PHMB), 1 % povidone-iodine (PVP-I), 4 % hydrogen peroxide, or undiluted Ringer's solution were concurrently in use. From 1984-1996, only 0.04 % PHMB or 1 % PVP-I were applied. From 1997, 0.04 % PHMB was used until the end of the study period in 2005.

RESULTS:
The combined rate for superficial and deep wound infection was 1.7 % in the 0.04 % PHMB group (n=3264), 4.8 % in the 1 % PVP-I group (n=2552), 5.9 % in the Ringer's group (n=645), and 11.7 % in the 4 % hydrogen peroxide group (n=643). Compared with all other treatment arms, PHMB showed the highest efficacy in preventing infection in traumatic soft tissue wounds (p<0.001). However, compared with PVP-I, the difference was only significant for superficial infections.

CONCLUSION:
The large patient numbers in this study demonstrated a robust superiority of 0.04 % PHMB to prevent infection in traumatic soft tissue wounds. These retrospective results may further provide important information as the basis for power calculations for the urgently needed prospective clinical trials in the evolving field of wound antisepsis.

KEYWORDS:
PHMB; antiseptics; hydrogen peroxide; polihexanide; povidone-iodine; traumatic soft tissue wounds; wound infection; wound irrigation

The treatment of critically colonized or locally infected wounds with local antimicrobial agents is a standard of care. The destruction of especially gram-negative bacteria potentially increases the endotoxin level in the wound. This in-vitro study aims to answer the question of whether and to what extent endotoxin release caused by the destruction of gram-negative bacteria is influenced by different wound dressing. Silver ion releasing dressings were compared to wound dressings with hydrophobic effect coated with dialkyl carbamoyl chloride (DACC). In addition, the bactericidal efficacy was measured. The log10 reduction factors (RF) against Pseudomonas aeruginosa were between 0 and 0.9 for the hyprophobic Dressings and 8.7 for the silver releasing dressing. The bacterial endotoxin content of the agar located under the dressing after contamination with P. aeruginosa was >300 <3,000 IU/ml in the case of a cotton gauze (control), >3,000 <30,000 IU/ml for DACC coated distance grid, >30 <300 IU/ml in for the DACC coated foam dressing and >0.3 <3 IU/ml in the case of the silver ion releasing dressing. The content of bacterial endotoxins which could be extracted from the wound dressing after contact with P. aeruginosa was >30,000 <300,000 IU/ml for the control dressing, >30,000 <300,000 IU/ml in the case of Cutimed Sorbact, >3,000 <30,000 IU/ml for the DACC coated foam dressing and >3 <30 IU/ml for the silver-releasing dressing. According to these findings, the silver ion releasing dressing has a higher antibacterial effect than wound dressings coated with DACC and it also releases a significantly lower amount of bacterial endotoxins.

Locally infected wounds and wounds colonised with multidrug-resistant bacteria are commonly treated with local antimicrobial agents. Recently, wound dressings have been introduced into clinical practice that reduces bacteria by adsorbing bacteria on the dressing surface by a hydrophobic effect. Our aim was to investigate, whether this hydrophobic effect is only present in dressings coated with dialkyl carbamoyl chloride (DACC) or also in other modern wound dressings.
To determine the hydrophobicity of the dressing surface contact angle measurements were performed. In addition, for selected wound dressings, the bacteria eliminating effect of the wound dressings for Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa were measured.
31 of the 34 wound dressings presented with a hydrophobic surface. The reduction factor (RF) of one wound dressing without coating was 1.6 for MRSA and RF 2.1 for P. aeruginosa. One with a DACC coated dressing showed a RF of 0.7 (MRSA) and 1.2 (P. aeruginosa). The RF of a wound dressing that releases silver ions was 6.1 for MRSA and 7.5 for P. aeruginosa respectively.
The results show that both uncoated and with DACC coated wound dressings can have hydrophobic surfaces. These hydrophobic dressings are able to adsorb bacteria onto their surface and consequently remove them from the wound. However, the RF for wound dressings that release silver ions is significantly higher.
Depending on the degree of contamination, these results can have an effect on the clinical decision to choose certain products. We assume that for e.g. infected or critically colonised wounds, wound dressings with a hydrophobic effect may not be sufficient to significantly improve the microbiological wound condition. However, this assumption has to be verified in clinical studies.

In the ongoing SARS CoV-2 pandemic effective disinfection measures are needed, and guidance based on the methodological framework of the European committee for standardization (CEN) can help to choose effective disinfectants on an immediate basis. This study aimed to elucidate whether disinfectants claiming "virucidal activity against enveloped viruses" as specified in the European Standard EN 14476 as well as in the german national DVV/RKI guideline are effectively inactivating SARS-CoV-2. Two commercially available formulations for surface disinfection and one formulation for hand disinfection were studied regarding their virucidal activity. Based on the data of this study the enveloped SARS-CoV-2 is at least equally susceptible compared to the standard test virus vaccinia used in EN 14476 or DVV/RKI guideline. Thus, chemical disinfectants claiming "virucidal activity against enveloped viruses" based on EN 14476 or DVV/RKI guideline will be an effective choice to target enveloped SARS-CoV-2 as a preventive measure.

Zielsetzung: Glutaraldehyd (GDA) besitzt ein breites Wirkspektrum gegen Mikroorganismen und wird daher in vielen Mitteln zur Instrumentendesinfektion verwendet. In der Vergangenheit wurden virusinaktivierende Eigenschaften dieser Produkte hauptsächlich auf Grundlage quantitati- ver Suspensionstests mit verschiedenen Testviren ermittelt. Inzwischen wurde die europäische Norm EN 17111:2018 veröffentlicht, welche die Untersuchung der Instrumentendesinfektionsmittel in einem Oberflächenträgertest unter praktischen Bedingungen ermöglicht. Daher ist es von Interesse, diesen wichtigen Wirkstoff vieler Instrumentendesinfektionsmittel auf die Fähigkeit zur Inaktivierung von Viren zu untersuchen, die in dieser europäischen Norm als Testviren ausgewählt wurden. 

Methode: Die viruzide Wirksamkeit von GDA als Wirkstoff in Instrumentendesinfektionsmitteln wurde mit 4 verschiedenen Testviren in einer Methode mit Simulation praktischer Bedingungen überprüft (EN 17111:2018).

Ergebnisse: Die Ergebnisse der Studie mit einer festen Expositionszeit von fünf Minuten bei 20°C zeigten, dass 100 ppm GDA für die Inaktivierung des Vaccinia-Virus erforderlich waren. Daraus resultiert die Einstufung als „begrenzt viruzid“ für Vorreinigungsprodukte. Für das Adenovirus wurden 125 ppm GDA benötigt, während für das murine Norovirus als Surrogat für das humane Norovirus 4.000 ppm GDA für eine signifikante Verringerung der Virustiter erforderlich waren. Beide nicht umhüllten Viren müssen gemäß EN 17111:2018 getestet werden, um den Nachweis einer viruziden Aktivität zu erbringen. Aber selbst 4.000 ppm reichten nicht aus, um eine Reduktion des murinen Parvo- virus um 4 log10 bei 20°C nachzuweisen. Dieses Virus wird mit dieser Methode aber nur bei Temperaturen ≥40°C eingesetzt.

Fazit: Zusammenfassend lässt sich sagen, dass GDA als Wirkstoff vieler Instrumentendesinfektionsmittel eine viruzide Wirksamkeit bei 20°C besitzt. Die notwendigen Konzentrationen hängen stark von der Stabi- lität der Testviren ab. GDA- Konzentrationen von 4.000 ppm bei einer 5-Minuten Einwirkzeit sind erforderlich, bedingt durch die ausgeprägte Stabilität des murinen Norovirus.

Cell culture methods are utilized ubiquitously in science and pharmaceutical and biotech industries. Sterility is one crucial factor for maintenance of cells and creation of valid data from experiments. As cells are usually cultured in CO2 incubators, those are one bottleneck in terms of sterility in a cell culture lab. This review gives an overview on the different sterilization procedures for CO2 incubators on the market with emphasize to considerations from a practical point of view. It compares sterilization by dry heat, steam, gas and ultraviolet radiation in terms of validity and practicability in accordance with international standards and regulations and transfers literature consensus about these methods to CO2 incubators. As conclusion, the authors give recommendations for a sterile working environment in line with good cell culture practice.

Ein elementarer Bestandteil der validierten Aufbereitung dentaler Übertragungsinstrumente ist die periodische Kontrolle des Aufbereitungserfolges durch eine Restproteinbestimmung mittels der OPA-Methode. Matrixeffekte zwischen Rückständen der zur manuellen Aufbereitung eingesetzten Chemikalien und dem OPA-Reagenz können die Proteinquantifizierung beeinflussen und zu massiv falsch-positiven Ergebnissen führen. Die vorliegende Arbeit zeigt erstmals eine neuartige Methode zur Eliminierung dieser Matrixeffekte. Durch Zugabe einer Zelltrümmersuspension zum OPA-Messansatz konnte eine Eliminierung der Matrixeffekte um 74 – 100 % erreicht werden.

Stellungnahme des Arbeitskreises Viruzidie beim Robert Koch-Institut (RKI), des Fachausschusses Virusdesinfektion der Deutschen Vereinigung zur Bekämpfung der Viruskrankheiten (DVV) e. V. und der
Gesellschaft für Virologie (GfV) e. V. sowie der Desinfektionsmittelkommission des Verbundes für Angewandte Hygiene (VAH) e. V.

Background: Various peracetic-acid (PAA)-based products for processing flexible endoscopes on the market are often based on a two-component system including a cleaning step before the addition of PAA as disinfectant. The peracetic acid concentrations in these formulations from different manufacturers are ranging from 400 to 1500 ppm (part per million). These products are used at temperatures between 20 °C and 37 °C. Since information on the virus-inactivating properties of peracetic acid at different concentrations and temperature is missing, it was the aim of the study to evaluate peracetic acid solutions against test viruses using the quantitative suspension test, EN 14476. In addition, further studies were performed with the recently established European pre norm (prEN 17111:2017) describing a carrier assay for simulating practical conditions using frosted glass.

Methods: In the first step of examination, different PAA solutions between 400 and 1500 ppm were tested at 20 °C, 25 °C, and 35 °C with three test viruses (adenovirus, murine norovirus and poliovirus) necessary for creating a virucidal action according to the European Norm, EN 14476. A second step for simulating practical conditions based on prEN 17111:2017 followed by spreading a test virus together with soil load onto a glass carrier which was immerged into a peracetic acid solution. A fixed exposure time of five minutes was used in all experiments.

Results: In the quantitative suspension test 1500 ppm PAA solution was needed at 35 °C for five minutes for the inactivation of poliovirus, whereas only 400 ppm at 20 °C for adeno- and murine norovirus were necessary. In the carrier assay 400 ppm peracetic acid at 20 °C were sufficient for adenovirus inactivation, whereas 600 ppm PAA were needed at 25 °C and 35 °C and 1000 ppm at 20 °C for murine norovirus. A PAA solution with 1000 ppm at 35 °C was required for complete inactivation of poliovirus. However, a dramatically decrease of titer after the drying and immerging could be observed. In consequence, a four log reduction of poliovirus titer could not be achieved in the carrier test.

Conclusion: In summary, 1500 ppm PAA at 35 °C was necessary for a virucidal action in the quantitative suspension test. After passing the requirements of the suspension test, additional examinations with adeno- and murine norovirus on glass carriers based on prEN 17111:2017 will not additionally contribute to the final claim of an instrument disinfectant for virucidal efficacy. This is due to the great stability of poliovirus in the preceded quantitative suspension test and the fact that poliovirus could not serve as test virus in the following carrier assay.

Keywords: Peracetic acid, Virucidal efficacy, Instrument disinfection

The World Health Organization (WHO) published two alcohol-based formulations to be used in healthcare settings and outbreak-associated infections, but inactivation efficacies of these products have not been determined against (re-) emerging viruses. In this study, we evaluated the virucidal activity of these WHO products in a comparative analysis. Zika virus (ZIKV), Ebola virus (EBOV), Severe Acute Respiratory Syndrome coronavirus (SARS-CoV), Middle East Respiratory Syndrome coronavirus (MERS-CoV) as (re-) emerging viral pathogens and other enveloped viruses could be efficiently inactivated by both WHO formulations implicating their use in healthcare systems and viral outbreak situations.

Aim: The virucidal efficacy of an automated ultrasound probe disinfector (trophon® EPR) was evaluated in a three step procedure according to European and German test methods. This system uses sonicated hydrogen peroxide mist (35%) at elevated temperature (50°C) in a closed chamber with control of all parameters within a 7 minute cycle.

Methods: In the first step of examination, the peroxide solution was tested in a quantitative suspension assay according to the Guideline of Deutsche Vereinigung zur Bekämpfung der Viruskrankheiten (DVV) e.V. and Robert Koch-Institute (RKI) and in parallel with the European Norm EN 14476 with all test viruses creating a virucidal claim.

In the second step, the virucidal efficacy of the hydrogen peroxide solution was evaluated in a hard surface carrier test according to the Guideline of DVV with adenovirus, murine norovirus and parvovirus simulating practical conditions.

Finally, the efficacy was evaluated by the automated system using stainless steel carriers inoculated with test virus and positioned at different levels inside the chamber.

Results: A ≥4 log10 reduction of virus titre was demonstrated with all methods including carrier tests with murine norovirus, adenovirus, and parvovirus using the automated device.

Conclusion: The automated device is able to inactivate test viruses of German and European norms and can therefore claim efficacy against human pathogenic enveloped and non-enveloped viruses. This includes human papillomaviruses which form part of the complete virucidal claim.

Keywords: disinfection, ultrasound probes, virucidal efficacy, trophon® EPR, human papillomaviruses

Zusammenfassung:

Zielsetzung: Die viruziden Eigenschaften der maschinellen Aufbereitung von vaginalen Ultraschallsonden (trophon® EPR) wurden in einem dreistufigen Prozess untersucht. Das System basiert auf der Vernebelung einer speziellen Peroxidlösung (35%) in einer geschlossenen Kammer bei erhöhter Temperatur (50°C) und einer Einwirkzeit von 7 min unter Kontrolle aller Parameter.

Methode: Im ersten Schritt wurde die Peroxidlösung in einem quantitativen Suspensionsversuch gemäß der Leitlinie der Deutschen Gesellschaft zur Bekämpfung von Viruskrankheiten e.V. (DVV) und des Robert Koch-Institutes und parallel gemäß der Europäischen Norm EN 14476 mit allen Prüfviren für eine viruzide Auslobung untersucht.

Im zweiten Schritt folgte ein Keimträgerversuch entsprechend der DVV-Leitlinie mit murinem Noro-, Adeno- und Parvovirus, um eine Viruzidie „high level“ zu zeigen.

Abschließend wurde die Wirksamkeit der maschinellen Aufbereitung mit den Viren der DVV-Leitlinie auf viruskontaminierten Edelstahlträgern überprüft.

Ergebnisse: Eine ≥4 log10 Reduktion des Virustiters konnte mit allen Methoden einschließlich der maschinellen Aufbereitung mit murinem Noro-, Adeno- und Parvovirus erreicht werden.

Schlussfolgerung: Die maschinelle Aufbereitung ist in der Lage, die Prüfviren der Deutschen und Europäischen Normen zu inaktivieren und erzielt damit den Anspruch, alle humanpathogenen behüllten und unbehüllten Viren einschließlich der humanen Papillomaviren zu inaktivieren, die Teil dieses resultierenden Claims einer kompletten Viruzidie sind.

Schlüsselwörter: Desinfektion, Ultraschallsonden, viruzide Wirksamkeit, trophon® EPR System, humane Papillomaviren

Hygienemotivation in Großküchen
- Einleitung
- Rationale Einschätzung der Situation vieler Unternehmen
- Einflussfaktoren auf die Mitarbeiter-Compliance
- Leizsätze der Hygienemotivation

Die Herstellung von Lebensmitteln unterliegt einer Vielzahl von Regularien im Rahmen des Lebensmittelrechts und der Lebensmittelkontrolle, deren oberstes Ziel der Gesundheitsschutz der Verbraucher ist.

Tuladhar et al. described a comparison between a propanol-based hand rub (Sterillium; BODE Chemie GmbH, Hamburg, Germany) and a hand soap (Unicura Hand soap; Colgate Palmolive, Weest, The Netherlands) for efficacy against murine norovirus (MNV) as a surrogate for human norovirus in a finger pad model. They reported that MNV infectivity reduction by washing hands with soap and water was significantly higher (P = 0.004) than treating hands with the rub. No residual virus was detected after handwashing in contrast to treatment with Sterillium.

Introduction: Skin antisepsis is an important measure to prevent postoperative infections. It is known that wound infections infringe the well-being of the patient and prolongs the rehabilitation significantly. At the same time additional costs will be caused in the health care system. Alcohol-based solutions containing the active ingredients chlorhexidine
gluconate [CHX] or octenidine dihydrochloride [OCT] have a residual antimicrobial effect on skin. This may re-sult in a better preventative outcome than alcohol alone.
Objectives: The aim of the presented study was to compare the immediate and long-term efficacy of CHX and OCT.
Methods: We performed a study on the skin on the arm of 20 healthy volunteers in a cross-over design based on DGHM standard method 13 and measured the colony forming units (cfu) of the resident skin flora after the application of the products according to Williamson and Kligman (1965). The cfu were determined directly after the application and after 24 h on 5 consecutive study days. The calculated log reduction factors were statistically evaluated with the student’s t-test.
Results: Both solutions showed as expected a significant any quick reduction of the resisdent skin flora and a long-term effect over 24 h. For OCT a statistically significant superior long-term effect after four applications was determined (lg reduction: (2.21 vs. 1.37; p = 0.004).
Conclusion: The presented data show that alcoholic solutions with octenidin dihydrochloride and chlorhexidine gluconate show a comparable efficacy on the resident skin flora. Alcohol-based preparations with the additional active octenidin dihydrochloride are a valid alternative for skin antisepics to the world-wide broadly used CHX-based products.

Virus inactivation by chemical disinfectants is an important instrument for infection control in medical settings, but the mechanisms involved are poorly understood. In this study, we systematically investigated the effects of several antiviral treatments on hepatitis C virus (HCV) particles as model for enveloped viruses. Studies were performed with authentic cell culture derived viruses and influence of chemical disinfectants, heat and UV treatment on HCV was analyzed by determination of infectious particles in a limiting dilution assay, quantitative RT-PCR, core ELISA and proteolytic protection assay. All different inactivation methods resulted in a loss of HCV infectivity by targeting different parts of the virus particle. Alcohols like ethanol and 2-propanol did not affect the viral RNA genome integrity, but disrupted the viral envelope membrane in a capsid protection assay. Heat and UV treatment of HCV particles resulted in direct damage of the viral genome as transfection of viral particle associated RNA into permissive cells did not initiate RNA replication. Additionally, heat incubation at 80°C disrupted the HCV envelope rendering the viral capsid susceptible to proteolytic digest. This study demonstrated the molecular processes of viral inactivation of an enveloped virus and should facilitate the development of effective disinfection strategies in infection control not only against HCV but also against other enveloped viruses.