Antimicrobial potential of sponge associated marine actinomycetes

Objectives. - The sponge-microbiat association is a potential chemical ecological phenomenon, which provides sustainable source of supply for developing novel pharmaceutical leads. Material and methods. - A total collection of 26 marine endosymbiotic actinomycete strains, isolated from the Bay of Bengal (coast of India), were screened for antagonistic and antimicrobial activity against pathogenic bacteria and fungi. Marine sponge agar was the most appropriate medium for the isolation of marine endosymbiotic actinomycetes. Results. - No unique actinomycetes association pattern was observed among the sponges. Among the total culturable microbial symbionts associated with Callyspongia diffusa, 38.46% were actinomycetes. The endosymbiotic marine actinomycetes exhibited potent antimicrobial activity against the growth of human pathogens. Particularly, the strains CPI 3, CPI 9, CPI 12 and CPI 13 showed the highest antimicrobial activity. Based on the RDP-11 classifier programme and conventional classification system, the potential producer CPI 13 was identified as Streptomyces spp. Conclusion. - The results of the present investigation revealed that, the marine actinomycetes from the sponges are a potential source of novel antibiotic leads. (C) 2007 Elsevier Masson SAS. All rights reserved.