Evaluation of the antibacterial activity of metarhizium anisopliae crude extract against selected waterborne bacteria

An abstract of the research paper presented to the Faculty of Veterinary Medicine, Universiti Malaysia Kelantan, in partial fulfillment of the course DVT 55204 – Research Project.
Metarhizium anisopliae is an entomopathogenic fungus that produces bioactive compounds with potential antimicrobial effects. Contamination of water by pathogenic bacteria poses a significant public health risk, as it can result in disease outbreaks. This study aimed to investigate the antibacterial activity of M. anisopliae crude extract against selected waterborne bacteria and to evaluate its potential as a natural antimicrobial agent. Three bacterial species commonly isolated from contaminated water, which are Aeromonas hydrophila, Enterobacter sp., and Staphylococcus aureus, were selected for this study. The crude extract of M. anisopliae was tested in vitro using the agar well diffusion method, and inhibition zones were measured to determine antibacterial activity. Results showed that the extract exhibited varying degrees of inhibition against the tested bacteria, with Aeromonas hydrophila demonstrating the highest susceptibility. Enterobacter sp. and Staphylococcus aureus were less susceptible, with smaller inhibition zones observed. The antibacterial effect of the extract was also influenced by concentration, indicating a dose-dependent response. Overall, the findings suggest that M. anisopliae crude extract has promising antibacterial potential, particularly against A. hydrophila, and could serve as an eco-friendly alternative for controlling waterborne bacterial pathogens. Further studies focusing on the purification of bioactive compounds and elucidation of the mechanism of action are recommended to optimize their application in water quality management.