Inhibitory Potential of Bacteriocins from Corynebacterium, Staphylococcus, and Bacillus sp. Against Multiple Resistant Bacterial Reference: A Comparative Study with Antibiotics

Abstract

Bacteriocins are antimicrobial peptides produced by bacteria that can function as an alternative to conventional antibiotics. The main objective of this work is to utilize bacterial metabolic products as an alternative to antibiotics. This study assessed the inhibitory capacity of bacteriocins obtained from Bacillus sp., Corynebacterium sp., and Staphylococcus sp. against various antibiotic-resistant bacterial infections. Bacteriocins were isolated and refined from Corynebacterium sp., Staphylococcus sp., and Bacillus sp. They were later employed as antibiotic compounds against pathogenic bacterial strains which are including Enterococcus faecalis ATCC 29212, Klebsiella pneumoniae ATCC 4352, Escherichia coli ATCC 25922, Bacillus cerus ATCC 11778, Pseudomonas aeroginosa ATCC 27853, Micrococcus luteus ATCC 9341, and Staphylococcus aureus ATCC 65389, that were isolated from clinical specimens and identified as pathogenic species and antibiotics resistant. Additionally, a total of five antibiotics were utilized as controls against the tested isolates. These antibiotics include Ampicillin (10 μg), Spectinomycin (25 μg), Streptomycin (10 μg), Meropenem (10 μg), and Penicillin (10 μg). The broth dilution method was employed in a 96-well microtiter plate for bacteriocins, while the Kirby-Bauer disc diffusion method was used for antibiotics. The results indicated that the bacteriocins synthesized by all three species possess antibacterial activity exclusively against Escherichia coli ATCC 25922 and Micrococcus luteus ATCC 9341, suggesting their potential as alternatives to conventional antibiotics. Nevertheless, their influence on other microorganisms that tested was not observed. The antibacterial efficacy of bacteriocins can be affected by several factors, including the concentration of NaCl, temperature, bacterial enzymes, and pH level. The study revealed that the most favorable circumstances for the antibacterial efficacy of bacteriocins were a pH of 6, a temperature of 35℃, and a NaCl concentration ranging from 1.5M to 2.5M.