Bacteriocin power: harnessing Lactobacillus acidophilus against pathogenic bacteria

The current study examined the antibacterial properties of Lactobacillus acidophilus (L. acidophilus) against infectious strains of Klebsiella pneumoniae (K. pneumoniae), Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) and aimed to find a natural way to treat microbial diseases. The antibacterial substances such as bacteriocin have been produced by lactic acid bacteria. Lactobacillus served as probiotics and reduce the antibiotic resistance pressure. L. acidophilus was isolated from a natural source (Yogurt) and grow on de Man Rogosa and Sharpe (MRS) agar media. The extraction of bacteriocin from MRS broth culture of one week incubation of L. acidophilus was done via ammounium sulphate precipitation method. Agar well diffusion method was used to evaluate the antibacterial activity of bacteriocin against these infectious strains. The values of zone of inhibition confirmed the potential of L. acidophilus as natural antibiotic agent. These test strains were characterized by Sanger sequence 16S ribotyping method. In terms of temperature, pH and concentrations, the results demonstrated that bacteriocin expressed significant antibiotic activity. Bacteriocin showed maximum antibacterial effect against E.coli at 80 °C and against S. aureus at 100mg/mL and against E.coli at pH 5. The bacteriocin’s efficacy was compared with antibiotic amoxil (500mg) as a positive control. One-way ANOVA analysis showed statistically significant variations in mean zone of inhibition. This study demonstrates that the bacteriocin produced by L. acidophilus has the ability to inhibit the growth of pathogenic bacteria. This antibacterial property of bacteriocin allows for potential treatments of various human and animal diseases, particularly against antimicrobial-resistant bacteria. Additionally, the findings indicate that the bacteriocin isolated from L. acidophilus becomes inactive at high pH levels and does not exhibit any bacteriostatic effects.