Bacteriophage-driven inhibition of biofilm formation in Staphylococcus strains from patients attending a Romanian reference center for infectious diseases

The increasing burden of invasive biofilm-related staphylococcal infections has led to a dire need for new agents to prevent biofilm formation. Bacteriophages may hypothetically alter a biofilm through several mechanisms, including induction of depolymerizing enzymes and lysis of persistent bacteria. We have assessed the influence of commercially available bacteriophage cocktails on Staphylococcus spp. clinical strains viability and biofilm formation. We analyzed 83 staphylococcal strains from patients consecutively admitted to a Romanian infection reference center from October 2014 through May 2015; the strains were characterized by phenotypic and genetic tools for their resistance and virulence features and for their phyliation. Experiments were performed in triplicate. Methicillin-susceptible strains were significantly more susceptible to all tested phages: 1.7-fold higher susceptibility for PYO, 1.4-fold for INTESTI, 2.9-fold for PHAGYO, 2.7-fold for PHAGESTI and 3.9-fold for STAPHYLOCOCCAL; t030 strains were significantly more susceptible to PYO and INTESTI compared with t127 strains. We identified a significant decrease in biofilm formation in the presence of both low and high PYO and INTESTI concentrations (P < 0.001). In conclusion, Staphylococcus strains from Romania displayed fairly good susceptibility to commercially available bacteriophages. We have also ascertained there is phage-driven in vitro inhibition of biofilm formation, the results potentially impacting prevention of prosthetic infections.