Effects of a bacteriocin produced by Streptococcus faecalis var. zymogenes (E-1) on susceptible microorganisms

The bacteriocin produced by Streptococcus faecalis var. zymogenes (E-1) is most active against Diplococcus pneumoniae and least against other strains of S. faecalis. Clostridium perfringens showed an intermediate susceptibility to the active principle. By utilizing the gas production of C. perfringens as an indicator of metabolic activity, a decrease in sensitivity to bacteriocin was demonstrated with aging of the culture. Non-viable pinpoint clostridial colonies frequently developed by exposure of C. perfringens to a 2 or 3 hr old E-1 broth culture. The action of E-1 as studied on C. perfringens appears to be bactericidal and only partially bacteriolytic. The extent of E-1 bactericidal activity on susceptible D. pneumoniae, C. perfringens, and S. faecalis was shown to be dependent upon bacteriocin concentration.