Inhibitory spectrum of a bacteriocinlike substance (mutacin) produced by some strains of Streptococcus mutans.

Streptococcus mutans strains were surveyed to determine their lysogenicity. Growth inhibition of the indicator strains around the inoculum of stab culture of some S mutans strains was demonstrated. Many gram-positive bacteria, including mycobacteria and streptomycetes, were sensitive to the antibacterial activity.