Evaluation of Antibacterial Effect of Bacteriocin Producing Lactic Acid Bacteria Isolated from Yoghurt and ‘Akamu’ on Selected Pathogenic Bacteria

Abstract

The rise of antibiotic resistance poses a significant threat to both human and animal health. As resistance to standard antibiotics becomes more prevalent, the need to discover new sources of effective Antimicrobial agent becomes inevitable. The study aimed to evaluate the antibacterial effect of bacteriocin-producing lactic acid bacteria isolated from yoghurt and ‘akamu’ on selected pathogenic bacteria. Bacteriocin-producing lactic acid bacteria (LAB) are considered ‘Generally Recognised as Safe’ (GRAS) and useful to control the fast development of pathogens. In this study, a total of 30 “akamu” samples comprising maize, millet and guinea corn (separately) and 10 brands of yoghurt were analysed using standard microbiological methods. Lactobacillus fermentum and Lactococcus lactis were identified as major isolates from the samples. Antibacterial effect of these isolates was confirmed by agar well diffusion method on selected pathogenic bacteria: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis and Salmonella spp. The presence of zones of inhibition in mm shows the production of bacteriocins by LAB. The largest zone of inhibition, measuring 54 ± 2.82 mm, was observed with Lactobacillus fermentum against Pseudomonas aeruginosa, while the least zone of inhibition 11±0.707 mm, was observed with Lactococcus lactis against Escherichia coli using ciprofloxacin as a control. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) tests were also done to provide a more detailed quantitative and qualitative information on the potency and therapeutic potential of Lactobacillus fermentum and Lactococcus lactis. Isolation of bacteriocin-producing lactic acid bacteria from ‘akamu’ and yoghurt is a good strategy to curb antibiotic resistance and its effect. The findings from this study highlighted the potential of isolates from Akamu and yoghurt for producing antimicrobial compounds (Bacteriocin) and exhibiting antimicrobial properties. This study underscored the potential of lactic acid bacteria in preventing microbial infections, which significantly contributes to combating antimicrobial resistance (AMR). Thus, consumption of ‘akamu’ and yoghurt should be encouraged as they are of rich health benefits.