Competition-mediated antibiotic induction in the marine bacterium Streptomyces tenjiimariensis

Microbial competition for limiting natural resources within a community is thought to me the selective force that promotes biosynthesis of antimicrobial compounds. The marine bacterium Streptomyces tenjimariensis produces the antibiotics istamycin A and B under select laboratory culture conditions; presumably the compounds serve an ecological role under natural conditions. Here we report results of a noel marine microbial competition experiment that examined the impact of co-culture of marine bacteria on istamycin production by S. tenjimariensis. Twelve of the 53 bacterial species tested (i.e., 22.6%) induced Istamycin production; this antibiotic also inhibited growth of the competitor colonies. These results suggest that marine bacterial metabolites serve an ecological role in countering competitive species.