BackgroundLong-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.MethodsUsing 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.ResultsIrrigation 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.ConclusionsThe 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.

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Objective: To perform a systematic review of the literature on bacterial resistance, tolerance and susceptibility of silver within the context of wound therapy using silver-based dressings. Methods: A literature search was carried out using PubMed, Embase and Cochrane Library databases, the focus was whether results from microbiological experimental in vitro tests with reference strains and clinical wound isolates are reflected in clinical practice with regards to their ‘resistance’ profiles, comparable with those observed for antibiotics. The search results were allocated to six categories: resistance and resistance mechanism, in vitro tests with standard strains and wound isolates, prevalence and incidence, impact on clinical practice and impact on antibiotic therapy as well as reviews, expert opinions and consensus. Results: Based on all findings of the literature, it cannot be confirmed that a related clinical resistance to silver-ions in silver-based dressings has clinical impact, although endogenous and exogenous genetic resistance patterns have been described and intensively investigated. A translation of these genetic resistance-expression structures to phenotypic appearances, similar to those known for antibiotics, has not been demonstrated for silver in the literature. Conclusion: It can be concluded that there is no definitive evidence available and further studies should be conducted.

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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.