Bacteriophage control of vancomycin-resistant enterococci in cattle compost

Aims: To isolate bacteriophage that infects vancomycin-resistant enterococci (VRE) and to investigate the ability of this phage to diminish VRE number in vitro and in experimentally VRE-inoculated compost. Methods and Results: We sampled 106 solid or water samples, including 101 bovine faecal samples; lytic phage named Vrep-5 was isolated from one bovine faecal sample by plaque assay using the clinical VRE isolate FN1 (Enterococcus faecium). Vrep-5 generated clear plaques 1 mm in diameter and exhibited characteristics of the family Myoviridae A1, with a spherical head (122 ± 16 nm) and a contractile tail (152 ± 17 nm long). Vrep-5 lysed other bacterial strains, including Enterococcus faecalis. Inoculation of vrep-5 into 0·5 g unsterilized compost experimentally inoculated with FN1 at the multiplicity of infection of 1500 (8·8 × 10⁴ CFU g^-1 VRE and 1·3 × 10⁸ PFU g^-1 vrep-5) led to a decrease of >3 log₁₀ in VRE abundance compared with the untreated control after 24 h of incubation. Conclusions: The data show that bacteriophage vrep-5 is effective in the rapid reduction in VRE colonization in compost. Significance and Impact of the Study: The present study gives valuable new knowledge in the fight against VRE in the animal production.