Pantnagar Journal of Research

Abstract

Azadirachta indica A. Juss (Neem) is a divine tree with diverse therapeutic properties. This study aims to evaluate the antibacterial potential of neem derived endophytic bacteria against pathogenic bacteria in the presence of neem leaf powder. In this experiment, three endophytic bacteria, namely Bacillus weidmannii DNS13, B. stercoris DNS14 and B. albus DNS16, were evaluated for antibacterial activity against pathogenic Staphylococcus aureus and Escherichia coli by adding different concentrations of neem leaf powder (0.1, 0.5, and 1 % w/v) using the agar well diffusion method. The results revealed that all endophytic bacteria exhibited larger zones of inhibition against S. aureus than E. coli. Further, supplementation of neem leaf powder delayed metabolite production, but the antibacterial activity was higher and more consistent than non-supplemented treatments. Among the three strains, DNS14 showed the highest zone of inhibition (21 mm) in the presence of 1% neem leaf powder and maintained antibacterial consistency up to 96 h of duration. The present findings highlight that amendment of neem leaf powder in the culture medium enhances the antimicrobial activity of neem derived endophytic bacteria against pathogenic bacteria