In Silico Characterization of Desert Locust-Derived Antimicrobial Peptides Against Drug-Resistant Bacteria

The critical need to find solutions to antibiotic resistance in pathogenic bacteria is becoming increasingly pronounced globally. In response to the urgent problems posed by the current public health challenges, our study adds to the growing body of knowledge by extracting insect peptides using acidified solvents, identifying the peptides from immune-challenged and nonimmune-challenged Schistocerca gregaria nymphs, and evaluating their antimicrobial activities against 9 clinical pathogens. A total of 96 unique peptides were identified, 91% from immune-challenged nymphs. Three specific antimicrobial peptides (AMPs) were common in immune-challenged and nonimmune-challenged individuals. Eleven and 27 peptides were categorized as high- and moderate-confidence AMPs, respectively, with sequence homologies ranging between 33% and 67%. The minimum inhibitory concentration (MIC) of peptide extract from immune-challenged nymphs ranged between 5 and 25 μg/mL, compared to 7.9-100 μg/mL from nonimmune-challenged nymphs. The lowest MIC values (< 8 μg/mL) were observed against Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, Escherichia coli, and Streptococcus agalactiae. It was observed that 87.5% of the AMP extracts had lower MIC values against Strep. agalactiae and Pseudomonas aeruginosa compared to tetracycline. The hemolytic activities due to peptide extracts from nonimmune-challenged (SPE-A) and immune-challenged (SPE-B) locust nymphs were < 5%. Our work underscores insects' promise as sustainable AMP contributors, offering recommendations for further research to unlock their full potential in the design of new antimicrobial agents to overcome bacterial drug resistance.