In vitro Antimicrobial Activity of Lactococcus Lactis sub spp lactis KG8 isolated from Sri Lankan Finger Millet

Abstract

Probiotic potential Lactic Acid Bacteria (LAB), Lactococcus Lactis.sub spp lactis KG 8 isolated from Sri Lankan finger millet variety Raavana was evaluated (In vitro) for its antimicrobial activity against fourteen human pathogens including Sensitive and Multi Drug Resistant(MDR) organisms; Escherichia coli ATCC 2592 and ATCC 35218, Staphylococcus aureus ATCC 6571, EMRSA 17 COCR and EMRSA 16 NCTC 13143, Enterococcus faecalis ATCC 49532 and ATCC 700802, Streptococcus mutans ATCC 25175, Streptococcus pyogenes ATCC 700294, S. sanguinis ATCC 10556, Streptococcus salvarius ATCC 13419, Salmonella enterica ATCC 700408, Acinetobactor baumannii ATCC 17978 and Shigella flexenari ATCC 12022. Agar well diffusion technique was applied in triplicate. Imipanum (10µg) was used as positive control and inhibition zone diameters were measured, and experiment was repeated thrice. Among the sensitive pathogens Shigella flexenari ATCC 12022 was significantly inhibited by L. Lactis.sub spp lactis KG 8 whereas, E. coli ATCC 2592 and Streptococcus pyogenes ATCC 700294 were moderately inhibited at the tested concentrations. However, Streptococcus sanguinis ATCC 10556 and Streptococcus mutans ATCC 25175 demonstrated resistance to L. Lactis.sub spp lactis KG 8. It was observed that, among the MDR pathogens, L. Lactis.sub sp lactis KG 8 could significantly inhibit S. aureus 16 EMRSA NCTC 13143 and Salmonella enterica ATCC 700408 and showed moderate antimicrobial activity against Escherichia coli ATCC 35218. Furthermore, Entercoccus faecalis ATCC 700802 demonstrated resistance to L. Lactis.sub sp lactis KG 8 at the tested concentrations. The In vitro antimicrobial activity of Lactococcus Lactis.sub spp lactis KG 8 indicates its ability to produce antimicrobial compounds and, therefore, it’s reported as a potential candidate for use in probiotic starter cultures.