Inhibitory relationships of resident bacteria isolated from the mantle fluids of Crassostrea virginica

Canadian Journal of Microbiology, Ahead of Print. Thirteen aerobic, halotolerant marine bacterial strains were isolated from the mantle fluids and associated mucus of the eastern oyster Crassostrea virginica harvested from the highly impacted Black Rock Harbor in western Long Island Sound. All isolated strains were Gram negative and had previously been identified using 16S RNA gene sequence analysis. These 13 strains were examined for their ability to inhibit the growth of each other employing a diffusion agar method used by antibiotic assays. All challenger strains were able to inhibit at least one of the indicator isolates. Enhanced antimicrobial activity was observed from cultures of Pseudoalteromonas sp. (L), Shewanella sp. (H), Thalassospira sp. (JA), and Alteromonas sp. (JB) when used to challenge the indicator isolates. The indicator isolate most sensitive to antimicrobial activity was another Pseudoalteromonas species (KC) whose growth was inhibited by 10 of the challenger strains, whereas Pseudoalteromonas (L) was resistant to all growth challenges. Growth autoinhibition was observed with isolates Tenacibaculum ascidiaceicola (KC), Vibrio (B), and Shewanella (H) during a 24  h incubation. No antimicrobial growth inhibition was detected when 24 and 48 h cell-free extracts of these isolates were used to challenge indicator isolate growth.
Source: Canadian Journal of Microbiology - Category: Microbiology Authors: Source Type: research