ABSTRACT
INTRODUCTION: We investigated the efficacy of a biocide Umonium38 on multidrug-resistant strains by comparison with a chloride derivative (Decs). METHODS: In vitro susceptibility tests were performed by agar diffusion disk and results were interpreted according to Clinical and Laboratory Standards Institute (CLSI). In vitro antibacterial efficacy of Umonium38 and Decs over selected strains was evaluated according to European Standards protocol with or without organic substance. RESULTS: In vitro tests with Umoniumnr at 2.5% concentration demonstrated an overall drop in microbial and yeast charges after 5 min. contact without organic substance. The same results were obtained in presence of organic substance. In vitro tests with chloride derivative at 5% without organic substance also resulted in overall drop in bacterial and mycotic charges. Conversely, in presence of organic substance, the hypochlorite reduced the initial 10 UFC/ml to 10 UFC/ml for all bacterial strains with a decrease of 4 log except for Enterococcus faecalis and Candida albicans whose reduction was 2 and 1 log units respectively. DISCUSSION: The organic substance in water requires large use of oxidising disinfectants (chloride, ozone) implying in the need for higher-than-standard concentrations. The disinfecting effect of chloride is only visible when the "requirement" of organic substance has been met. By contrast, Umonium38 behaves like a powerful biocide even in presence of organic substance, as it is not "consumed" by possible organic residues. CONCLUSIONS: Umonium38 resulted beneficial and effective. It is to be stressed, however, that all these experiments were in vitro tests and still requires validation from a correct use of clinical practice.
