Longitudinal analysis of the prevalence of Lactobacillus species according to culture and tRFLP with advancing pregnancy Finally, we examined the trends in the occurrence of the distinct Lactobacillus species as indentified through culture and tRFLP with advancing pregnancy. When accounting for the subsequent trimesters L. crispatus was present in 42, 49, and 60 of the 100 women respectively, L. jensenii in 27, 33, and 32 patients, and L. gasseri/iners in 59, 57, and 49 subjects, respectively. Accordingly, there was a significant

positive trend in the occurrence of L. crispatus (χ2 test-for-trend JPH203 in vitro = 6.46, p = 0.011), while there was no significant trend in the prevalence of L. jensenii (χ2 test-for-trend = 0.59, p = 0.4), nor in the occurrence of L. gasseri/iners (χ2 test-for-trend = 2.01, p = 0.2). Hence a significant increase in the presence of L. crispatus with grade I VMF (prevalence ratio 1.32, 95% CI 1.01 – 1.72, p = 0.04) from the first to

the third trimester was observed, whereas conversely there was a trend towards a decreased presence of L. gasseri/iners with grade I VMF (prevalence ratio 0.77, 95% CI 0.56 – 1.06, p = 0.1), albeit non-significant. Consequently while there was no significant trend in the prevalence of normal VMF with advancing pregnancy in this cohort, a larger number of women with normal VMF gained L. crispatus. Discussion The vaginal lactobacilli were originally described in the late 19th century by German gynaecologist Albert Döderlein, who purported that the lactobacilli act as a barrier buy BIRB 796 of defence preventing unless other bacteria to ascend the genital tract [19]. Since then, it has been established that the vaginal lactobacilli are indeed capable of providing colonisation

resistance through a variety of mechanisms. Nonetheless, failure of the lactobacilli-driven defence often occurs, resulting in overgrowth of the vaginal epithelium by other bacteria, as observed, most typically, with anaerobic polymicrobial overgrowth in bacterial vaginosis and less commonly with overgrowth by bifidobacteria [7, 8] and other bacteria. From this perspective, major interest in the study of the vaginal lactobacilli has emerged in recent years, as it is assumed that thorough characterisation of the normal vaginal microflora may provide us with a better understanding of the mechanisms Selleck CBL-0137 involved with the stability of lactobacilli-dominated microflora, or conversely, with their failure to maintain the vaginal ecosystem. It was recently established that of the 80 known Lactobacillus species, up to 20 different species may colonize the intestinal tract, yet merely four species seem to dominate the vaginal microflora, in particular L. crispatus, L. jensenii, L. gasseri and L. iners [7, 17, 18], a finding that has now been corroborated in various parts of the world among women with differing ethniCity[20], albeit a fifth species L. vaginalis may have been overlooked by culture-independent methods (unpublished data).