Inactivation of the ciaH Gene in Streptococcus mutans diminishes mutacin production and competence development, alters sucrose-dependent biofilm formation, and reduces stress tolerance.

Many clinical isolates of Streptococcus mutans produce peptide antibiotics called mutacins. Mutacin production may play an important role in the ecology of S. mutans in dental plaque. In this study, inactivation of a histidine kinase gene, ciaH, abolished mutacin production. Surprisingly, the same mutation also diminished competence development, stress tolerance, and sucrose-dependent biofilm formation.