Isolation of Streptococcus mutans temperate bacteriophage with broad killing activity to S. mutans clinical isolates

Bacteriophages are expected to be therapeutic agents against infectious diseases. Streptococcus mutans are involved in dental plaque formation related to dental caries and periodontitis. In S. mutans, lytic bacteriophages have been isolated previously, but the isolation of temperate bacteriophage has not been reported although their presence in the genome has been confirmed. Here, we report the isolation of temperate bacteriophage, 9KSM96, from S. mutans. 9KSM96 has a circular DNA 39,820 bp long and reveals Siphoviridae morphology. 9KSM96 shows a broad range of susceptibility against S. mutans strains with different serotypes. By the addition of 9KSM96, S. mutans growth and biofilm formation were significantly inhibited. In cocultures of S. mutans with other bacterial species, the proportion of S. mutans significantly decreased in the presence of 9KSM96. In summary, 9KSM96 shows selective anti -S. mutans activity. The isolation of temperate bacteriophage is important for future genetic manipulation to create more efficient bacteriophages.