[Evaluation of group B streptococcus susceptibility to lactic acid bacteria strains]

Streptococcus agalactiae (Group B streptococci--GBS) is one of the coexistent components of vaginal microflora. Lactic Acid Bacteria (LAB) are the predominant bacteria in the physiological flora of vagina. The production of antagonistic substances like short chain fatty acids, hydrogen peroxide, bacteriocin-like substances protects against multiplication of pathogenic microorganisms. However, during pregnancy there is a disturbance of vaginal microflora and there are optimal conditions for bacterial or candidal vaginitis. Despite sufficient protection of LAB during pregnancy, Streptococcus agalactiae is one of the microorganisms, which can multiply and it is dangerous for newborns. The aim of the study was the assessment of antagonistic activity of chosen species of LAB to GBS strains. Antagonism between LAB and GBS was tested in a mixture of fluid 24 hrs cultures and the results were determined quantitatively by serial dilutions. Susceptibility of GBS strains to LAB activity was analyzed according to serotypes of GBS strains (Ia, Ib-V) and to place of isolation of GBS strains (there are three groups: GBS strains isolated from vagina of carriers; vaginal GBS strains isolated from women, who had clinical symptoms of vaginitis and GBS strains isolated from blood of children, who were ill with sepsis). The obtained results indicated strong inhibitory activity of Lactobacillus species to GBS strains after 2 hrs duration. Statistically significant dependence was found in the susceptibility of GBS strains to Lactobacillus. L. plantarum has shown the strongest activity against GBS strains. There were no statistically significant relationship found in the susceptibility of GBS to LAB activity between serotypes of GBS and between investigated groups of GBS.