title: Characterization of the vaginal microbiota of healthy Canadian women through the menstrual cycle.
abstract: BACKGROUND
  The vaginal microbial community plays a vital role in maintaining women's health. Understanding the precise bacterial composition is challenging because of the diverse and difficult-to-culture nature of many bacterial constituents, necessitating culture-independent methodology. During a natural menstrual cycle, physiological changes could have an impact on bacterial growth, colonization, and community structure. The objective of this study was to assess the stability of the vaginal microbiome of healthy Canadian women throughout a menstrual cycle by using cpn60-based microbiota analysis. Vaginal swabs from 27 naturally cycling reproductive-age women were collected weekly through a single menstrual cycle. Polymerase chain reaction (PCR) was performed to amplify the universal target region of the cpn60 gene and generate amplicons representative of the microbial community. Amplicons were pyrosequenced, assembled into operational taxonomic units, and analyzed. Samples were also assayed for total 16S rRNA gene content and Gardnerella vaginalis by quantitative PCR and screened for the presence of Mollicutes by using family and genus-specific PCR.
  
  
  RESULTS
  Overall, the vaginal microbiome of most women remained relatively stable throughout the menstrual cycle, with little variation in diversity and only modest fluctuations in species richness. Microbiomes between women were more different than were those collected consecutively from individual women. Clustering of microbial profiles revealed the expected groupings dominated by Lactobacillus crispatus, Lactobacillus iners, and Lactobacillus jensenii. Interestingly, two additional clusters were dominated by either Bifidobacterium breve or a heterogeneous mixture of nonlactobacilli. Direct G. vaginalis quantification correlated strongly with its pyrosequencing-read abundance, and Mollicutes, including Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum, were detected in most samples.
  
  
  CONCLUSIONS
  Our cpn60-based investigation of the vaginal microbiome demonstrated that in healthy women most vaginal microbiomes remained stable through their menstrual cycle. Of interest in these findings was the presence of Bifidobacteriales beyond just Gardnerella species. Bifidobacteriales are frequently underrepresented in 16S rRNA gene-based studies, and their detection by cpn60-based investigation suggests that their significance in the vaginal community may be underappreciated.
authors: Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada.
authors: Bonnie
authors: B
authors: Chaban
authors: Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada ; Agriculture and AgriFood Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada.
authors: Matthew G
authors: MG
authors: Links
authors: Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada.
authors: Teenus Paramel
authors: TP
authors: Jayaprakash
authors: Department of Obstetrics and Gynecology, University of British Columbia, 1190 Hornby Street, Vancouver, BC V6Z 2K5, Canada ; Women's Health Research Institute, 4500 Oak Street, Vancouver, BC V6H 3N1, Canada.
authors: Emily C
authors: EC
authors: Wagner
authors: Women's Health Research Institute, 4500 Oak Street, Vancouver, BC V6H 3N1, Canada.
authors: Danielle K
authors: DK
authors: Bourque
authors: Women's Health Research Institute, 4500 Oak Street, Vancouver, BC V6H 3N1, Canada.
authors: Zoe
authors: Z
authors: Lohn
authors: Women's Health Research Institute, 4500 Oak Street, Vancouver, BC V6H 3N1, Canada.
authors: Arianne Yk
authors: AY
authors: Albert
authors: Department of Obstetrics and Gynecology, University of British Columbia, 1190 Hornby Street, Vancouver, BC V6Z 2K5, Canada ; Women's Health Research Institute, 4500 Oak Street, Vancouver, BC V6H 3N1, Canada.
authors: Julie
authors: J
authors: van Schalkwyk
authors: Department of Microbiology and Immunology, University of Western Ontario and Lawson Health Research Institute, London, ON, Canada.
authors: Gregor
authors: G
authors: Reid
authors: National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada ; Department of Microbiology & Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada.
authors: Sean M
authors: SM
authors: Hemmingsen
authors: Department of Veterinary Microbiology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4, Canada.
authors: Janet E
authors: JE
authors: Hill
authors: Department of Obstetrics and Gynecology, University of British Columbia, 1190 Hornby Street, Vancouver, BC V6Z 2K5, Canada ; Women's Health Research Institute, 4500 Oak Street, Vancouver, BC V6H 3N1, Canada.
authors: Deborah M
authors: DM
authors: Money
keywords: Bifidobacteriales; Bifidobacterium; Gardnerella; Lactobacillus; Menstrual cycle; Mollicutes; Mycoplasma; Ureaplasma; Vaginal bacteria; Vaginal microbiome; cpn60