Objective This study was undertaken to characterise the dominant species of Lactobacillus colonising the vagina of healthy pregnant women, to examine some of their phenotypic and genotypic properties, and to gain a better understanding of the potential role of species, which might be associated with infection-free status.Design A prospective descriptive cohort study.Setting Department of Obstetrics and Gynaecology, Medical University of Vienna and Medical School, Vienna, Austria.Sample A total of 200 women in the late first trimester of pregnancy without clinical signs of vaginal infection were included in the study. Of these, 126 women were found to have a normal vaginal flora based on Gram stain.Methods Culture probes from those 126 women were further processed for identification of Lactobacillus species. Overall, 168 colonies from 84 women were identified as belonging to the Lactobacillus genus. Based on the combined results of microbiological methods and genus-specific, multiplex, and species-specific polymerase chain reaction, lactobacilli were recovered from 72 women.Main outcome measures Identification of Lactobacillus species of the vaginal flora of healthy pregnant women.Results The most frequently occurring species were Lactobacillus crispatus and Lactobacillus gasseri, followed by Lactobacillus jensenii and Lactobacillus rhamnosus.Conclusions Our results may have implications on the composition and on the use of Lactobacillus preparations for the prevention of recurrent vaginal infection.

Certain properties relevant to probiotic action, e.g. resistance to acid, bile tolerance, adhesive properties, antibacterial activity, and antibiotic susceptibility were investigated of lactobacilli isolated from four kinds of Thai traditional fermented foods. Media of pH = 2.0-7.0 and bile salt concentrations of 0.3-1.0%were used as stress conditions. The adhesive properties were assessed by determination of bacterial hydrophobicity. Antibacterial activity of the probiotic lactobacilli was determined by means of the spot-on-lawn method. Among 563 isolates, only 3 strains (two from fermented pork and one from fermented tea leaves) showed extremely high survival rates under stress caused by acid or bile salts. The identification by PCR techniques revealed that these three strains were Lactobacillus fermentum. The strains from fermented pork showed higher adhesive potential than those from fermented tea leaves. The three strains inhibited test pathogenic bacteria to different extents. They were sensitive to chloramphenicol, quinupristin, erythromycin, kanamycin linezolid, rifampicin, streptomycin, and tetracycline but resistant to ciprofloxacin and vancomycin.

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Miang is a kind of traditional fermented tea leaves, widely consumed in northern Thailand as a snack. It contains several kinds of Lactobacilli spp. The aim of this study was to isolate strains of Lactobacillus fermentum from miang and to investigate their antibacterial and antioxidant activities. The agar spot and well assays were used for determination of antibacterial power. The antibacterial mechanism was investigated by cell morphologic change under scanning electron microscope (SEM). Antioxidant activity was studied by means of free radical scavenging and ferric reducing power assays. The acid and bile screening tests indicated that L. fermentum FTL2311 and L. fermentum FTL10BR presented antibacterial activity against several pathogenic bacteria: Listeria monocytogenes DMST 17303, Salmonella Typhi DMST 5784, Shigella sonnei DMST 561 (ATCC 11060) and Staphylococcus aureus subsp. aureus DMST 6512 (ATCC 6538Ptm). The results from SEM suggested that the antibacterial action was due to the destruction of cell membrane which consequently caused the pathogenic cell shrinking or cracking. The antioxidant study suggested that both L. fermentum FTL2311 and L. fermentum FTL10BR strains could liberate certain substances that possessed antioxidant activity expressed as trolox equivalent antioxidant capacity (TEAC) and equivalent concentration (EC) values for free radical scavenging and reducing mechanisms, respectively. The supernatant of L. fermentum FTL2311 broth revealed TEAC and EC values of 22.54±0.12 and 20.63±0.17 >M.mg-1 respectively, whereas that of L. fermentum FTL10BR yielded TEAC and EC values of 24.09±0.12 and 21.26±0.17 >M.mg-1 respectively. These two strains isolated from miang present high potential as promising health-promoting probiotics.