Antimicrobial Protein Produced by VaginalLactobacillus acidophilusthat inhibitsGardnerella vaginalis

Abstract

Objective:To isolate bacteriocin from a vaginal strain ofLactobacillus acidophilus.Methods: L. acidophilus160 was grown on two media. The first was MRS broth for 18 hours; the cells were harvested, washed, and placed into a chemically defined medium. The second medium resembled vaginal fluid minus protein. Bacteriocin was precipitated from both media using ammonium sulfate. The growth-inhibiting activity of bacteriocin was determined by a bioassay using nine different isolates ofGardnerella vaginalis.Results:MRS broth is not a suitable medium for extracting bacteriocin, because it binds with Tween 80. Bacteriocin was isolated, without contaminating constituents, from chemically defined medium and identified as a single band by electrophoresis. Bacteriocin has a molecular weight of 3.8 kDa. All nine isolates ofGardnerellawere inhibited by the bacteriocin isolated fromL. acidophilus160.Conclusions:Bacteriocin produced byL. acidophilus160 was isolated from the chemically defined medium (starvation medium) in a partially pure form.L. acidophilus160 bacteriocin inhibited growth of all nine isolates ofGardnerella vaginalis.