Efficient removal of hospital pathogens from hard surfaces by a combined use of bacteriophages and probiotics: potential as sanitizing agents

Purpose Many hospital-acquired infections (HAI) can be transmitted by pathogens contaminating hospital surfaces, not efficiently controlled by conventional sanitation, which can indeed contribute to the selection of multidrug-resistant (MDR) strains. Bacteriophages have been suggested as decontaminating agents, based on their selective ability to kill specific bacteria. However, there are no data on their stability in detergents and their potential use in routine sanitation. On the other hand, a probiotic-based sanitation (Probiotic Cleaning Hygiene System, PCHS) was recently shown to stably reduce pathogens on treated surfaces. However, its action is not specific and slow, being based on competitive antagonism. This work was aimed to assess the effectiveness of a combined use of phages and PCHS in removing HAI-associated pathogens from different hard surfaces. Methods The decontamination ability of phages in PCHS was tested in vitro and in situ, against drug-susceptible or resistant S. aureus, E. coli and P. aeruginosa strains, and using bacterial densities similar to those detected on hospital surfaces. Results Phages targeted efficiently all tested bacteria, maintaining their full activity when added to PCHS detergent. Notably, the combined use of phages and PCHS not only resulted in a rapid reduction (up to >90%) of the targeted pathogens, but, due to the stabilizing effect of probiotics, the pathogens were maintained at low levels (>99%) also at later times, when instead the effect of phages tends to diminish. Conclusion These results suggest that a combined biological system might be successfully used in hospital sanitation protocols, potentially leading to an effective and safe elimination of MDR pathogens from the hospital environment.