Modes of Resistance to Benzylpenicillin and Ampicillin in Twelve Klebsiella Strains

Abstract

Summary: Strain b1, an avirulent non-slime-producing variant of Pseudomonas solanacearum k60, had greater bacteriocinogenic activity than did strain k60 both in liquid and on solid medium. The bacteriocin synthesized by strain b1 inhibited the growth of 43 of 51 P. solanacearum strains tested. It had no effect on strain b1, strain k60, or selected strains from 10 other bacterial species. Although the optimal growth temperature for strain b1 was 32°C, the temperature most favourable for bacteriocin production was 30°C. Bacteriocin titre could be increased by short exposure to ultraviolet light but not by chemical inducing agents.