Inhibition of bacterial pathogens by lactobacilli

Lactobacilli produce many antimicrobial substances including organic acids, hydrogen peroxide and bacteriocins. Antagonistic activity of lactobacilli is an important factor in the protection of the vagina of fertile women aga inst infection by certain pathogens. In the present study, we investigated 17 strains of lactobacilli, including 11 strains of vaginal origin. The aim was to investigate in more detail the antibacterial activity of lactobacil li and to attempt to assess substances responsible for inhibition. The inve stigated lactobacilli inhibited some strains of Escherichia coli, Serratia marcescens, Shigella boydii, Listeria monocytogenes, Listeria ivanovii, Lis teria innocua and Staphylococcus aureus. We have provided evidence that inh ibition is due mainly to organic acids and to a lesser extent, to bacterioc ins.