Antibacterial activity of probiotics isolated from commercialized yogurt against pathogenic bacteria

Probiotics have garnered considerable attention as potential agents for inhibiting pathogenic bacteria due to their beneficial effects on gut health and immune modulation. The study aimed to identify probiotic strains with significant antibacterial potential that could be used as natural alternatives to traditional antibiotics. The antibacterial activity of cell-free supernatant (CFS) and cell lysate (CL) of both LAB isolates against skin and food-borne bacteria was observed via disc diffusion assay, where the inhibition zone sizes ranged from 8.5 ± 0.15 mm to 12.0 ± 0.82 mm in diameter. The standard broth dilution was performed to estimate the MIC and MBC values for both isolates, which exhibited 25-50 g/mL values against Gram-positive bacteria, while against Gram-negative bacteria, the values ranged between 12.5-100 µg/mL. Only the CL of both isolates exhibited bactericidal effects on the tested bacteria with a ratio ≤ 4. This study's inhibitory effects and results have proven the presence of antibacterial composition in commercial yoghurt as a natural agent that can inhibit the growth of common skin and food-borne pathogenic bacteria. As the issue of antibiotic resistance continues to grow, this study offers promising implications for developing alternative, sustainable antibacterial interventions to safeguard public health.