Abstract
BackgroundThe vaginal microflora is important for maintaining vaginal health and preventing infections of the reproductive tract. The rectum has been suggested as the major source for the colonisation of the vaginal econiche.MethodsTo establish whether the rectum can serve as a possible bacterial reservoir for colonisation of the vaginal econiche, we cultured vaginal and rectal specimens from pregnant women at 35-37 weeks of gestation, identified the isolates to the species level with tRNA intergenic length polymorphism analysis (tDNA-PCR) and genotyped the isolates for those subjects from which the same species was isolated simultaneously vaginally and rectally, by RAPD-analysis.One vaginal and one rectal swab were collected from a total of each of 132 pregnant women at 35-37 weeks of gestation. Swabs were cultured on Columbia CNA agar and MRS agar. For each subject 4 colonies were selected for each of both sites, i.e. 8 colonies in total.ResultsAmong the 844 isolates that could be identified by tDNA-PCR, a total of 63 bacterial species were present, 9 (14%) only vaginally, 26 (41%) only rectally, and 28 (44%) in both vagina and rectum. A total of 121 (91.6%) of 132 vaginal samples and 51 (38.6%) of 132 rectal samples were positive for lactobacilli. L. crispatus was the most frequently isolated Lactobacillus species from the vagina (40% of the subjects were positive), followed by L. jensenii (32%), L. gasseri (30%) and L. iners (11%). L. gasseri was the most frequently isolated Lactobacillus species from the rectum (15%), followed by L. jensenii (12%), L. crispatus (11%) and L. iners (2%).A total of 47 pregnant women carried the same species vaginally and rectally. This resulted in 50 vaginal/rectal pairs of the same species, for a total of eight different species. For 34 of the 50 species pairs (68%), isolates with the same genotype were present vaginally and rectally and a high level of genotypic diversity within species per subject was also established.ConclusionIt can be concluded that there is a certain degree of correspondence between the vaginal and rectal microflora, not only with regard to species composition but also with regard to strain identity between vaginal and rectal isolates.These results support the hypothesis that the rectal microflora serves as a reservoir for colonisation of the vaginal econiche.
Highlights
The vaginal microflora is important for maintaining vaginal health and preventing infections of the reproductive tract
These results support the hypothesis that the rectal microflora serves as a reservoir for colonisation of the vaginal econiche
Studies of vaginal lactobacilli have demonstrated that L. crispatus, L. jensenii, L. gasseri and L. vaginalis are the most commonly recovered species of H2O2-producing lactobacilli [5,6,7,8,9] and the absence of H2O2-producing lactobacilli in the vagina has been associated with an increased risk for bacterial vaginosis (BV) [10,11]
Summary
The vaginal microflora is important for maintaining vaginal health and preventing infections of the reproductive tract. The rectum has been suggested as the major source for the colonisation of the vaginal econiche. Several bacterial species are known to colonize both the gastrointestinal and the reproductive tract, and the rectum has been suggested to play an important role as a source or reservoir for organisms that colonize the vagina [2,3]. It is important to establish to which degree this is the case for lactobacilli, the predominant group of microorganisms of the normal vaginal microflora, because these bacteria are generally known to produce endogenous microbicides such as lactic acid, which acidifies the vagina, and hydrogen peroxide (H2O2), toxic to other bacteria and viruses, including HIV [4]. BV has been linked to increased shedding of HIV in the female genital tract [12], increased acquisition of HIV [10] and herpes simplex virus type 2 [10,12] and with preterm birth [13].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
