Identification and genotyping of bacteria from paired vaginal and rectal samples from pregnant women indicates similarity between vaginal and rectal microflora

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.

Establishment of a sensitive system for analysis of human vaginal microbiota on the basis of rRNA-targeted reverse transcription-quantitative PCR

“…L. vaginalis belonging to the L. reuteri subgroup which has been reported to be detected in the human vaginal tract (Fredricks et al, 2005;Verhelst et al, 2004), was also detected in 50% of the subjects. Although, Lactobacillus species such as Lactobacillus casei, Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus oris, L. reuteri, Lactobacillus rhamnosus, Lactobacillus helveticus and Lactobacillus salivarius have been reported to be detected as the minor populations in the vaginas of healthy or BV subjects (El Aila et al, 2009;Verhelst et al, 2005;Zhou et al, 2007), such species were not detected in any subjects tested in this study. All of these species should have been covered by the subgroup/ species primer sets if their amounts exceed the detection limit of RTqPCR, suggesting that Lactobacillus populations in the Japanese subjects might be limited to the simple composition.…”

Actinomyces and Related Organisms in Human Infections

“…Fecal samples were shown to harbor only a few clones identified as Actinomyces, with "A. viscosus" and A. odontolyticus being represented (42). Actinomyces species found in the human (female) urogenital tract in the absence of actinomycetal infection include A. meyeri, A. neuii, A. radingae, A. turicensis, and A. urogenitalis (43)(44)(45)(46)(47). After the detection of Actinobaculum schaalii (currently Actinotignum schaalii), a taxon closely related to the members of the genus Actinomyces, in urine, groin swabs, and vaginal swabs (18), it was recently suggested that this organism might be a relatively frequent commensal residing on the skin and mucosae of urogenital sites, but not in the colon, since no detection from feces was made (48).…”

The Iron-Repressed, AraC-Like Regulator MpeR Activates Expression of fetA in Neisseria gonorrhoeae

“…Gonococcal strain FA1090 did not utilize iron from salmochelin S4 but did obtain iron from S2. As microbial producers of enterobactin, DHBS and salmochelin inhabit the same niche as the gonococcus (21,55), it seems likely that the ability to hijack these siderophores, in the presence of neutrophil-derived siderocalin, enhances the survival of N. gonorrhoeae in vivo.…”