Antibacterial Activity of Lactic Acid Bacteria Isolated from Healthy Human Vagina Against Sexually Transmitted Disease Organisms
Lactic acid bacteria (LAB), namely, Lactobacillus acidophilus 1, Lactobacillus acidophilus 2, Lactobacillus brevis 1, Lactobacillus rhamnosus 1, Lactococcus lactis subsp. lactis 1, Lactococcus lactis subsp. lactis 2, Lactococcus raffinolactis 1, Pediococcus acidilactici 1, Pediococcus pentosaceus 1, and Pediococcus pentosaceus 2 were isolated from healthy female vaginal fluid and characterized to species level by Analytical Profile Index (API) kit. L. acidophilus 1 was found to be predominant with 25.5% occurrence. Metabolites produced by LAB inhibited the growth of Candida albicans, Gardnerella vaginalis and Neisseria gonorrhoeae with 25 mm zone of inhibition. L. lactis subsp. lactis 2 produced the highest (0.051 g/l) quantity of hydrogen peroxide; P. acidiclactici produced the highest (8.6 g/l) quantity of diacetyl, while L. lactis subsp. lactis 2 produced the highest (11.8 g/l) quantity of lactic acid. The entire LAB produced bacteriocin that inhibited the growth of all the sexually transmitted disease (STD) pathogens used in this work with the exception of L. rhamnosus 1 and P. pentosaceus 2. Proteinase K and pepsin were shown to completely destroy bacteriocin activity while catalase and amylase have no effect on the activity of bacteriocin.
Key words: lactic acid bacteria, vaginal fluid, sexually transmitted disease pathogens, Analytical Profile Index kit, enzymes activity