Journal of Entomological Research

In vitro antimicrobial activity of acidified methanol extracts of individuals of sixteen dung beetle species ‘challenged’ (with overnight grown culture of Escherichia coli) was determined by kirby-Baer disk diffusion bioassay. extracts from ‘unchallenged’ individuals were also screened for antimicrobial activity along with tetracycline as positive control in bioassays. considerable variation in antimicrobial activity was observed between ‘unchallenged’ and ‘challenged’ extracts and between the species. the highest mean zone of inhibition was observed in extracts of Copris repertus (283.84 ± 202.06 mm²) and (267.86 ± 237.48 mm²) at 10 and 20 h post-treatment, respectively. Among the test microorganisms the highest mean zones of inhibition of 179.79 ± 120.08 mm² and 188.34 ± 125.85 mm² were recorded against Staphylococcus aureus at 10 and 20 h posttreatment, respectively. the mean zone of inhibition of the extracts against E. coli was 166.51 ± 166.43 mm² and 128.49 ± 119.86 mm² at 10 and 20 h post-treatment, respectively. the antimicrobial activity against E. coli was particularly important since the strain of E. coli used in the study was resistant to all antibiotics, including Methicillin. the mean zone of inhibition of the extracts against Candida albicans was 26.56 ± 43.13 mm² and 30.44 ± 44.46 mm² at 10 and 20 h post-treatment, respectively.