Study on the decononisation of urinary tract catheters applaying a practice-like in vitro test method

FHH Brill, S Pahl, JH Klock, H Gabriel, H Brill, J Hambach, C Jänicke, A Arndt

Meeting abstracts from International Conference on Prevention & Infection Control (ICPIC 2017), Geneva, Switzerland. 20-23 June 2017; Antimicrobial Resistance & Infection Control 2017 6(Suppl 3):P243, DOI: 10.1186/s13756-017-0201-4 - P243 - Urinary tract 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