Potential use of phages as sanitizing agents to reduce hospital pathogens on hard surfaces

Introduction: Hospital-acquired infections (HAI) can be transmitted by pathogens persistently contaminating hospital surfaces,1 often multidrug-resistant (MDR), and not efficiently controlled by conventional sanitation protocols, which indeed contribute to selection of drug-resistant strains.2 Due to the selective killing of specific bacteria, bacteriophages have been repeatedly suggested as decontaminating agents.3,4 This work was aimed to assess phage usability as sanitizing agents in routine hospital sanitation. Materials & Methods: Phage activity was assessed in vitro and in situ, in aqueous buffer or probiotic eco-sustainable detergents,5 on glass, plastic or ceramic surfaces artificially contaminated by S. aureus, E. coli and P. aeruginosa. Both ATCC strains and wild-type MDR hospital isolates were used, at a density consistent with what detected on hospital surfaces. Results: Phage application significantly reduced (up to 90%) all tested bacteria on all treated surfaces. Notably, phages suspended in probiotic detergents not only retained their full activity, but resulted even more effective especially at later times. Conclusions: Results suggest that phages might be successfully included in probiotic detergents currently used for hospital sanitation, potentially resulting in innovative products highly effective in the safe elimination of MDR nosocomial pathogens from the hospital environment. References: 1. Otter JA, Yezli S, French GL. The role played by contaminated surfaces in the transmission of nosocomial pathogens. Infect Control Hosp Epidemiol 2011; 32(7): 687-99. 2. Wand ME, Bock LJ, Bonney LC, Sutton JM. Mechanisms of Increased Resistance to Chlorhexidine and Cross-Resistance to Colistin following Exposure of Klebsiella pneumoniae Clinical Isolates to Chlorhexidine. Antimicrob Agents Chemother 2017; 61(1). 3. Jensen KC, Hair BB, Wienclaw TM, et al. Isolation and Host Range of Bacteriophage with Lytic Activity against Methicillin-Resistant Staphylococcus aureus and Potential Use as a Fomite Decontaminant. PLoS One 2015; 10(7): e0131714. 4. Tomat D, Quiberoni A, Mercanti D, Balague C. Hard surfaces decontamination of enteropathogenic and Shiga toxin-producing Escherichia coli using bacteriophages. Food Res Int 2014; 57: 123-9. 5. Caselli E, D'Accolti M, Vandini A, et al. Impact of a Probiotic-Based Cleaning Intervention on the Microbiota Ecosystem of the Hospital Surfaces: Focus on the Resistome Remodulation. PLoS One 2016; 11(2): e0148857.