Abstract

The upsurge in antimicrobial resistance has spurred the search for new antimicrobial substances. Insects are promising sources of antimicrobials, and their antimicrobial activity is attributed to their ability to disrupt microbial membranes. This study evaluated the antimicrobial potential of extracts from Ants (Pheidole megacephala), cockroaches (Periplaneta americana), and termites (Macrotermes bellicosus) obtained from the Rivers State University school farm against bacterial and fungal isolates. Shigella spp., Escherichia coli, Salmonella spp., Staphylococcus spp., Candida sp., Aspergillus sp and Mucor sp. were obtained from the clinical laboratory, Rivers State University. The insect extracts were prepared using standard methods, and antimicrobial susceptibility was determined using the agar disc diffusion method on freshly prepared Mueller-Hinton agar. Results showed that antimicrobial activities of the insects were dependent on the dose and the insect type. The antibacterial activity of the ant, cockroach and termite at 100% concentration on Shigella sp. was 20.0±0.6, 20.0±0.7 and 15.0±0.5 mm, respectively. For Salmonella sp. at 100% concentration, the zone of inhibition was 0.0±0.0, 32.0±0.7 and 19.0±0.5 mm for the ant, cockroach and termite. The zone diameter of the ant, cockroach and termite extract on Staphylococcus sp. at 100% was 12.0±0.5, 19.0±0.6 and 10.0±0.5 mm. The zone diameter of the ant, cockroach and termite extract on E. coli was 35.0±0.7, 16.0±0.6 and 15.0±0.5 mm. The zone diameter of the ant, cockroach and termite extract on Candida sp at 100% was 0.0±0.00, 14.0±0.58 and 7.0±0.50 mm. The zone diameter of the ant, cockroach and termite extracts on Aspergillus sp. and Mucor sp. was (0.0±0.00, 0.0±0.00 and 8.0±0.58 mm) and (0.0±0.00, 9.0±0.2 and 6.0±0.50 mm), respectively. Although the antimicrobial activity of the insect extracts varied, cockroach extracts exhibited better antibacterial and antifungal activity than the ant and termite extracts.