ABSTRACT

This study aims to compare the antimicrobial activity of lactic acid bacteria (LAB) species isolated from ogiri against three common human pathogens. The LAB isolates and pathogens was identified following a four step analysis namely; cultural, microscopic, biochemical examination and sugar utilization. The antagonistic properties of these isolates against Escherichia coli, Staphylococcus aureus and Salmonella species were examined using agar well diffusion method. Three LAB isolates namely LAB 1, LAB 2, and LAB3 identified as Lactobacillus brevis, Lactobacillus plantarum and Lactobacillus fermentum respectively were effective against all selected pathogen strains. Amongst the three isolates, LAB2 exhibited the highest antibacterial activity, against all the indicator pathogens tested followed by LAB 1 and the least LAB3. LAB2 showed antibacterial activity was maximum against E.coli with a zone of inhibition ranging from (12.6mm) and least for Salmonella spp (6.9mm). LAB1 also showed antimicrobial property against all tested pathogens showing highest activity against E.coli (12.5mm) and least against Staphylococcus aureus (6.1mm). The least antimicrobial activity showed in isolate LAB3 against E.coli (11.2mm) and against S.aureus (9.4mm). The degree of antimicrobial property among the isolates was in the order of LAB2>LAB1>LAB3. Generally, the LAB isolates showed remarkable inhibitory effect against both Gram positive and Gram negative pathogenic strains. However, the spectrum of inhibition was different for the isolates tested. These results suggest that these LAB isolates could be used as a natural bio-preservatives in different food products or even as therapeutic agent (probiotics) .