title: Identification and genotyping of bacteria from paired vaginal and rectal samples from pregnant women indicates similarity between vaginal and rectal microflora.
abstract: BACKGROUND
  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.
  
  
  METHODS
  To 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.
  
  
  RESULTS
  Among 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.
  
  
  CONCLUSIONS
  It 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.
authors.affiliation: Laboratory Bacteriology Research, Department of Clinical Chemistry, Microbiology & Immunology, University of Ghent, Ghent, Belgium. Nabil.ElAila@UGent.be
authors.forename: Nabil Abdullah
authors.initials: NA
authors.lastname: El Aila
authors.forename: Inge
authors.initials: I
authors.lastname: Tency
authors.forename: Geert
authors.initials: G
authors.lastname: Claeys
authors.forename: Hans
authors.initials: H
authors.lastname: Verstraelen
authors.forename: Bart
authors.initials: B
authors.lastname: Saerens
authors.forename: Guido Lopes Dos Santos
authors.initials: GL
authors.lastname: Santiago
authors.forename: Ellen
authors.initials: E
authors.lastname: De Backer
authors.forename: Piet
authors.initials: P
authors.lastname: Cools
authors.forename: Marleen
authors.initials: M
authors.lastname: Temmerman
authors.forename: Rita
authors.initials: R
authors.lastname: Verhelst
authors.forename: Mario
authors.initials: M
authors.lastname: Vaneechoutte
mesh_terms: D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D007778:Lactobacillus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D011247:Pregnancy; D012343:RNA, Transfer / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique; D012007:Rectum / Q000382:microbiology*; D014621:Vagina / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial; D012343:RNA, Transfer