Bioprospecting of insect nest associated actinobacteria with special reference to antimicrobial and anti HIV activity

Abstract

The present study attempted to explore actinobacteria from different insect nest samples for antimicrobial activity. Totally, 43 actinobacterial colonies were recovered from ant nest, termite nest, wasp nest and blanket worm nest samples by adopting standard spread plate method. Screening of antimicrobial properties of actinobacterial strains was determined by agar plug method. Two actinobacterial strains AN1 and AN5 showed promising activity (14-18 mm inhibition) against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, carbapenem resistant Klebsiella pneumoniae and Mycobacterium smegmatis. Both the strains produced antimicrobial compound earlier on ISP2 agar when compared to ISP2 broth. Crude extracts from the strains AN1 and AN5 were produced by adopting agar surface fermentation and extracted using ethyl acetate. Based on the studied phenotypic characteristics, actinobacterial strains AN1 and AN5 isolated from ant nest were identified as Streptomyces sp. In addition to antimicrobial activity, extracts also showed anti-HIV activity. This study concluded that insect nest is a promising source for bioactive actinobacteria. Two potential Streptomyces sp. AN1 and AN5 isolated from ant nest will be promising sources for antimicrobial metabolites against drug resistant bacteria, retrovirus and mycobacterial pathogens.