Novel copper resistant and antimicrobial Streptomyces isolated from Bay of Bengal, India

Seventy actinomycetes isolates isolated from soil from Bay of Bengal were screened for antagonistic activity against some pathogenic bacteria Bacillus subtilis (BS), Escherichia coli (EC), Klebsiella pneumoniae (KP), Micrococcus luteus (ML), Proteus vulgaris (PV), Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA) and 15 fungal pathogens. Out of these isolates, the three strains A160, A161 and A164 inhibited growth of the Gram-positive bacteria, B. subtilis, M. luteus and S. aureus as well as few fungal pathogens, Aspergillus flavus, A. niger, Candida albicans, Fusarium semitectum, Rhizoctonia solani and Botrytis cinera. However, the strain A161 inhibited the growth of the gram negative bacteria E. coli, K. pneumoniae, P vulgaris and P. aeruginosa. These three strains showed copper resistance up to 480 mg l(-1) and showed variability in sensitivity to different class of antibiotics. The strains A160 and A164 were more sensitive to antibiotics, but A161 was found resistant. The strain A160 showed the production of nitrate reductase, and all the three strains exhibited variability in utilization of carbon sources such as galactose, sucrose, L-arabinose, sorbitol, mannitol, melezitose and ONPG. Molecular analysis based on 165 rDNA homology revealed the taxonomic affiliation of these strains, A160 and 5164 as Streptomyces spp. and strain A161 as S. fradiae. (C) 2009 Elsevier Masson SAS. All rights reserved.