Influence of a probiotic-based sanitizing method on surface pathogen persistence and resistence: an effectiveness and safety study.

Background: Contamination of hospital surfaces can contribute to transmission of healthcare-associated infections (HAIs), representing a global concern. Chemicals-based cleaning shows limitations in controlling surface bioburden, and can select resistant species. Recently, a system based on detergents containing probiotics of the spore-forming Bacillus genus (PCHS) was shown to decrease surface pathogens up to 90% more than conventional disinfectants. Aim(s)/Objective(s): Here we wanted to analyse the impact of PCHS on the drug-resistance features of the hospital surfaces microbiota, and to assess its safety of use. Method(s): Microbial drug-resistance was analysed by a microarray detecting 84 resistance-genes in the total microbiota and in individual isolates, and confirmed by conventional antibiograms. Also, a four year microbiological surveillance was implemented, evaluating the presence of Bacillus strains in all the clinical samples of the patients admitted to PCHS-treated hospitals. Results: PCHS use induced a drop (up to −99%) of resistant pathogen strains, rather than selecting them. Notably, detergent-Bacillus strains remained genetically unmodified even after years of continuous contact with surface pathogens, and no infections attributable to Bacillus were observed in 32,139 analysed samples from seven hospitals. Discussion and/or Conclusion(s): Results showthat PCHS application can effectively reduce the number of pathogens and their drug resistance. Furthermore, the genetic stability of PCHS-Bacillus trains, together with the absence of HAI attributable to probiotic Bacilli suggest that they do not have the ability to cause infections, even in the subjects at higher risk for adverse events, such as hospitalized patients, and support the safety of environmental use of probiotics for sanitation purposes.