Antibacterial activity of lactobacillus species isolated from raw goat milk against Staphylococcus aureus
World Journal of Biology Pharmacy and Health Sciences, 6 (2):
065-072 (May 2021)DOI: 10.30574/wjbphs.2021.6.2.0055
Abstract
Lactobacillus spp. are known to have many health benefits and are mostly used as probiotics. They can cause inhibition of certain micro-organisms by the reduction of pH due to production of lactic acid, hydrogen peroxide and antimicrobial compounds such as bacteriocins. The antibacterial; activity of Lactobacillus spp. Against Staphylococcus aureus was evaluated using agar well diffusion method. Three raw goat milk samples were pooled together, serially diluted, cultured on MRS (De Man, Rogosa, Sharpe) Agar, and purified. Four Lactobacillus species were isolated and identified by biochemical tests as L. lactis, L. plantarum, L. Casei and L. Fermentum. Antibacterial activity of the four isolates against the test organism, Staphylococcus aureus, was determined by agar well diffusion method following the extraction of crude and precipitated bacteriocin from the isolates. All the isolates produced antagonistic effects against the test organism with maximum zones of growth inhibition produced by precipitated bacteriocin 14.0mm (L. casei) to 16.0mm (L. lactis) whereas minimum zones of growth inhibition was produced by crude bacteriocin 8.0mm (L. casei) to 11.0mm (L. lactis). The results obtained confirmed that the four Lactobacilli isolated have growth inhibitory effects against Staphylococcus aureus and can therefore serve as important probiotic organism. It also goes further to show the importance of Lactobacillus bacteriocins as food bio-preservatives. This therefore justifies an in-depth investigation for the identification and application of these organisms in generating alternative antibacterial therapies for human and animal diseases to counter the problem of bacteria antibiotic resistance in recent years.