Lysis of Streptococcus mutans cells with mutanolysin, a lytic enzyme prepared from a culture liquor of Streptomyces globisporus 1829

Abstract

A collection of reference and clinically-isolated strains of Streptococcus mutans and other streptococci were compared with regard to susceptibility to mutanolysin. This is a cell wall lytic enzyme prepared from a culture supernatant of Streptomyces globisporus 1829. Cells grown in Trypticase soy broth or brain-heart infusion broth were examined for lysis with mutanolysin, under various experimental conditions, with or without detergent. Most of the Strep. mutans strains studied were significantly lysed by the action of mutanolysin, especially when the incubation time was prolonged or if higher concentrations of the enzyme were used. Serotypes c, e and f strains were relatively resistant to the lytic action of mutanolysin as compared to strains of other serotypes. However, the viability of the cells of these strains was markedly decreased by mutanolysin treatment. The addition of a high concentration of sodium chloride after incubation with mutanolysin rapidly lysed the cells, even when the cells were seemingly resistant to the enzyme action. The simultaneous presence of sodium lauroyl sarcosinate and mutanolysin degraded the cells more rapidly and more extensively than the enzyme alone. Many other species of streptococci, including cariogenic strains, were also susceptible to the lytic action of mutanolysin.