Biological Characteristics and Anti-Biofilm Activity of A Lytic Phage Against Vancomycin-Resistant Enterococcus Faecium

Background and objectives: an important leading cause of the emergence of vancomycin-resistant enterococci, especially enterococcus faecium, is the inefficiency of antibiotics in the elimination of drug-resistant pathogens. consequently, the need for alternative treatments is more necessary than ever. materials and methods: a highly effective bacteriophage against vancomycin-resistant e. faecium called vb-efms-s2 was isolated from hospital sewage. the biological properties of phage s2 and its effect on biofilm structures were determined. results: phage s2 was specifically capable of lysing a wide range of clinical e. faecium isolates. according to electron microscopy observations, the phage s2 belonged to the siphoviridea family. suitable ph spectra for phage survival was 5-11, at which the phage showed 100% activity. the optimal temperature for phage growth was 30-45°c, with the highest growth at 37°c. based on one-step growth curve results, the latent period of phage s2 was 14 min with a burst size of 200 pfu/ml. the phage s2 was also able to tolerate bile at concentrations of 1 and 2% and required mg2+ for an effective infection cycle. biofilms were significantly inhibited and disrupted in the presence of the phage. conclusion: according to the results, phage s2 could potentially be an alternative for the elimination and control of vancomycin-resistant e. faecium biofilm.