Antimicrobial Activity of Metabolites of Various Strains of Lactobacillus acidophilus

The antimicrobial activity of metabolites of eight strains of Lactobacillus acidophilus (FTDC 2804, FTDC 0785, FTDC 8592, FTDC 1295, FTDC 4793, FTDC 4462, FTDC 0582 and FTDC 2916) against Staphylococcus aureus (gram positive) and Escherichia coli (gram negative), was examined and compared using agar well diffusion method. Lactobacillus acidophilus was cultivated in two different types of dairy growth medium namely, full cream milk and skim milk. The results showed that the metabolites of all the eight strains had significant antimicrobial effect based on zone of inhibition results when compared to control. There was a statistically significant difference in the zone of inhibition data for Staphylococcus aureus and Escherichia coli among the metabolites of the eight strains cultivated in the two different growth medium. Certain L. acidophilus strains were more effective against Staphylococcus aureus, while other strains were more effective against Escherichia coli. On the other hand, the growth medium had no significant influence on the antimicrobial effect of metabolites of seven strains except L. acidophilus FTDC 4462 against Escherichia coli. As for Staphylococcus aureus, the growth medium only affected the antimicrobial effect of metabolite of strain L. acidophilus FTDC 1295, but did not affect the antimicrobial effect of metabolites of the other seven strains. It can be concluded that L. acidophilus cultivated in dairy products produced metabolites with antimicrobial property, which could provide beneficial medicinal values to human