Isolation and biochemical characterization of mutacin VSM43 isolated from human oral Streptococcus mutans VSM43

Bacteriocins produced by mutans streptococci are known as mutacins. Streptococcus mutans VSM43 isolated from human clinical oral cavity was screened for the production of mutacin. It can inhibit the growth of other mutans streptococci, many other gram-positives and some gram-negative bacteria. Average size of the inhibitory zone ranged between 12-20mm. The inhibitory activity could not be related to organic acids, bacteriophages and hydrogen peroxide. Mutacin VSM43 was protease sensitive, remained active within a pH range of 2-8, and lost activity after heating at 100 degrees C for 30 min. Mutacin VSM43 was dialyzable through dialysis membrane (pore size 12,000 Da). A titre of 1280 arbitrary/activity units per ml (AU/mL) was shown against Staphylococcus aureus AB211. Lacuna frequency percentage (LF%) against Streptococcus mutans VSMD and Staphylococcus aureus AB211 was 37% and 49% respectively. We are convinced mutacin VSM43 may be a parallel candidate for use against dental caries.