Open AccessAnalysis on the antimicrobial activity of some lactic acid bacteria strains
Author(s) -
Ioan Sârbu,
Facultatea de Biologie Departamentul de Genetică,
Tatiana Vassu,
Ileana Stoica,
Carmen Chifiriuc,
Marcela Bucur,
Elena Rusu,
Robertina Ionescu,
Diana Pelinescu,
Bucureşti Universitatea „Titu Maiorescu“
Publication year - 2015
Publication title -
romanian journal of infectious diseases
Language(s) - English
Resource type - Journals
eISSN - 2069-6051
pISSN - 1454-3389
DOI - 10.37897/rjid.2015.2-3.6
Subject(s) - bacteriocin , antimicrobial , lactic acid , lactobacillus paracasei , bacteria , microbiology and biotechnology , lactococcus lactis , lactobacillus , strain (injury) , chemistry , nisin , biology , genetics , anatomy
Objective. The main objective of this study was to select lactic acid bacteria strains with antimicrobial activity and to identify and characterize the antimicrobial compounds. Methods. In this study we tested the antimicrobial activity of 153 lactic bacteria strains by disk diffusion method against 6 microbial pathogenic strains isolated from patients with urinary and vaginal infections. Results. Antimicrobial test results revealed that most of lactic acid bacteria strains exhibited high antimicrobial activity against pathogenic microorganisms. For most of lactic bacteria strains antimicrobial activity has been correlated with the production of organic acids and only for two strains with the biosynthesis of bacteriocins. Bacteriocin produced by Lactococcus (Lc.) lactis F2a strain presented a broad spectrum of activity and high activity (51,200 AU/ml) compared with bacteriocins isolated from Lactobacillus (Lb.) paracasei ssp. paracasei JR strain (400 AU/ml). The stability tests of bacteriocin revealed that the bacteriocin produced by Lc. lactis F2a strain, it is stable at acid pH while exposure for long time to 600C causes a drastic decrease in bacteriocin activity. Conclusions. Lactic bacteria strains showed a high antimicrobial activity against both prokaryotic and eukaryotic pathogen strains. Two bacterial strains have bacteriocins. Bacteriocins isolated from Lc. lactis F2a strain showed a high activity and a broad spectrum of action.