Antimicrobial and anti-tubercular potential of Streptomyces lomondensis SACC 63 isolated from soil samples in Himachal Pradesh, India

Aim: The antimicrobial and anti-tubercular potential of Actinobacteria isolated from soil in Himachal Pradesh, India, was examined in this study. Methodology: The bioactive metabolites produced from five selected Actinobacterial cultures SACC-63, SACC-75, SACC-76, SACC-77 and SACC-N10 by agar surface fermentation were tested for their antimicrobial and anti-tubercular efficacy in in-vitro. The taxonomy of SACC-63 was identified as Streptomyces lomondensis using 16S-rRNAsequence analyses. Results: The ethyl acetate extract of strain SACC-63 showed broad spectrum activity against wide range of bacterial and fungal pathogens at 250 µg per disc concentration. In anti-tubercular screening by luciferase reporter phage (LRP) assay, four actinobacterial strains showed more than 65% inhibition against the standard strain Mycobacterium tuberculosis H37Rv and multi drug resistant (MDR) M. tuberculosis strain at 100 µg ml-1 and 500 µg ml-1 concentrations, except the strain SACC-N10. The MIC values of SACC-63 against microbial pathogens ranged between 62.5 µg ml-1 and 250 µg ml-1 The strain SACC-63 showed 99% similarity with Streptomyces spp. Further, phylogenetic analysis based on 16S rRNA revealed a close relationship between SACC-63 and S. lomondensis. Interpretation: The present study suggested that S. lomondensis SACC-63 isolated from Himachal Pradesh region in India could be a promising source for the production of bioactive molecules.