Characterization of a temperate bacteriophage isolated from the ruminant-derived Streptococcus bovis/equinus complex.

Although Streptococcus bovis/equinus complex (SBSEC) lysogens are prevalent in the rumen, studies on prophages experimentally induced from these strains are limited. Herein, we screened inducible prophages from ruminant-derived SBSEC strains, including the newly reported S. ruminicola, leading to the characterization of a representative temperate phage. We successfully induced a temperate phage (vB_SbS-proRumen) from S. ruminicola KCCM 90354, which has a broad host range, capable of lysing several SBSEC strains and other lactic acid bacteria. The vB_SbS-proRumen belongs to the Siphovirus, characterized by a short latent period, high burst size, and stability across pH and temperature conditions typical of subacute ruminal acidosis. The phage also demonstrates potent anti-biofilm activity. The vB_SbS-proRumen has a 38,092 bp double-stranded DNA genome with 58 predicted open reading frames, sharing high similarity and conserved genetic organization with other previously predicted SBSEC prophages. This study provides valuable insights into the diversity and plasticity of SBSEC phages.