Antimicrobial peptides: Could cecropin A and nisin be new promising agents for the treatment of anaerobic infections.

Antimicrobial peptides (AMPs) may mitigate the danger of increasing antimicrobial resistance. We aimed to determine the activities of catestatin, temporin A, nisin and cecropin A against Bacteroides fragilis ATCC 25285, Prevotella melaninogenica ATCC 25845, Cutibacterium acnes ATCC 6919, Peptostreptococcus anaerobius ATCC 27337 and Peptostreptococcus stomatis DSM 17678. strains. The susceptibility of all anaerobic bacteria was determined by Kirby-Bauer disc diffusion method, agar dilution and broth microdilution method, recommended by CLSI. By broth microdilution the MIC of temporin A for P. anaerobius was 500µg/mL, and MBC >500µg/mL. The MIC of nisin for P. melaninogenica was 200µg/mL, with a MBC of 400µg/mL, for C. acnes, P. anaerobius, and P. stomatis, MIC were 40mg/mL. The MIC of cecropin A for B. fragilis was 50µg/mL, MBC was 500µg/mL. For C. acnes, the MIC was 4µg/mL, MBC was 8µg/mL. The MIC for P. melaninogenica, P. anaerobius and P. stomatis were 8µg/mL, with corresponding MBC values of 16, 32 and 50µg/mL, respectively. Conversely, catestatin proved ineffective against all strains. In conclusion, our study, demonstrated that cecropin A and nisin showed promising results against anaerobic standard strains. We believe thatfurther research conducted to explore those AMPs could hold promise as a treatment option for anaerobic bacterial infections.