Antimicrobial Activity of Ircinia sp; a Marine Sponge and Its Associated Bacteria from Andaman Coast

摘要

Marine sponges and their surface associated bacteria are recognized as sink of many important bioactive compounds. A total of 28 bacterial isolates associated with the marine sponge, Ircinia sp. collected from North Bay, Andaman were screened for their antimicrobial activity against selected pathogens viz., Aeromonas hydrophila, Bacillus subtilis, Enterococcus durans, Streptococcus lentus, Klebsiella pneumoniae and Rolstonia solanacearum using disc diffusion assay. The bacterial isolates were identified based on their biochemical properties and were assigned to Vibrio sp., Aeromonas sp., Bacillus sp., Corynebacterium sp., Pseudomonas sp., Streptococcus sp., Enterococcus sp., Neisseria sp., Veillonella sp., Citrobacter sp. and Klebsiella sp. Of the total bacterial isolates tested, 66.67% were found to have antimicrobial properties ranging from broad spectrum to species specific. One of the isolates, I12 which was identified as Lysinibacillus fusiformis based on DNA sequence homology of 16S rDNA gene, inhibited Aeromonas hydrophila with about 120% of the efficiency of erythromycin. The present findings highlight the importance of sponge surface–associated bacteria in producing new natural compounds