Antibacterial potentials of extracts from Gryllotalpa gryllotalpa, Pentodon algerinum grubs, and Gypsonoma euphraticana larva frass

Abstract

Objectives: The overuse and abuse of antibiotics have accelerated antibiotic resistance, and to solve this problem, it has been found that many insect species have potential antimicrobial properties against a wide range of resistant pathogens. Our study tests the antibacterial activity of microbial defensive compounds included in body extract of insects inhabiting contaminated environments and frass of phytophagous insects. Materials and Methods: Through sequential extraction method by acidic methanol, chloroform, and hexane solvents, insect body extract of Gryllotalpa gryllotalpa, grubs of Pentodon algerinum besides feces of Gypsonoma euphraticana larvae were tested against Gram-positives Bacillus cereus, Bacillus coagulans, Staphylococcus aureus, and Salmonella typhi, Escherichia coli, and Klebsiella pneumoniae. The antibiotics ceftriaxone (CRO) and ampicillin (AM) were used as standard drugs. The antibacterial growth inhibition was estimated by well diffusion methods. Results: High significant antibacterial activity against the tested bacteria by acidic methanol then chloroform extracts, while hexane extract of all the three insect species only produced significant growth inhibition of S. aureus. In addition, growth inhibition 20.0 mm or more was induced by: MeOH extracts of G. gryllotalpa and P. algerinum for S. typhi and E. coli, besides chloroform G. gryllotalpa extract for S. typhi. The tested bacteria S. aureus, S. typhi, and K. pneumoniae were AM-resistant, while E. coli was both AM and CRO-resistant. Conclusion: Acidic meOH and chloroform body extract of G. gryllotalpa and P. algerinum and larvae G. euphraticana feces extract possess bioactive compounds with promising antibacterial properties, for overcoming antibiotic resistance.