Preliminary screening for antibacterial and antimycobacterial activity of actinomycetes fr om less explored ecosystems.

Radhakrishnan, M.; Suganya, S.; Balagurunathan, R.; Kumar, V.

World Journal of Microbiology and Biotechnology; 2010; 26; 561-566.

Abstract: Actinomycetes from less explored ecosystems were screened for antibacterial and antimycobacterial activity. Crude bioactive compounds were produced by growing these strains by shake flask fermentation using soybean meal medium. Culture supernatant and mycelia were extracted with ethyl acetate and methanol, respectively. Antibacterial activity of crude extracts was tested by disc diffusion method against gram positive and gram negative bacteria. Actinomycete strains D10, D5, NEK5, ANS2, M104 and R2 showed prominent activity. Culture filtrates and crude extracts were tested against standard strain Mycobacterium tuberculosis H 37 Rv and drug sensitive and drug resistant clinical isolates of M. tuberculosis by luciferase reporter phage (LRP) assay. Considerable variation was observed in antimycobacterial activity between actinomycete culture filtrates and solvent extracts. Actinomycete strains viz., D10, D5 (desert), CSA14 (forest), CA33 (alkaline soil), NEK5 (Neem plant), MSU, ANS2, R2 and M104 (marine) screened in the present study were found to be highly potent showing good antibacterial and antimycobacterial activity. Five of them such as A3, CSA1, EE9, ANS5 and R9 were exclusively active against M. tuberculosis . Secretary products of actinomycetes of rare ecosystems are meant to antagonize organisms in their respective environments. These are likely to be novel antimycobacterial compounds as they unknown to human pathogens.

Keywords: Actinomycetes; Less explored ecosystems; Antimycobacterial activity; LRP assay; Streptomyces

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