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Association between vaginal washing and detection of Lactobacillus by culture and quantitative PCR in HIV-seronegative Kenyan women: a cross-sectional analysis
  1. Erica M Lokken1,
  2. Griffins Odhiambo Manguro2,
  3. Amina Abdallah2,
  4. Caroline Ngacha2,
  5. Juma Shafi2,
  6. James Kiarie2,
  7. Walter Jaoko3,
  8. Sujatha Srinivasan4,
  9. Tina L Fiedler4,
  10. Matthew M Munch4,
  11. David N Fredricks4,5,
  12. R Scott McClelland1,2,5,6,
  13. Jennifer E Balkus1,4,6
  1. 1 Department of Epidemiology, University of Washington, Seattle, Washington, USA
  2. 2 Institute of Tropical & Infectious Diseases, University of Nairobi, Nairobi, Kenya
  3. 3 Department of Medical Microbiology, University of Nairobi, Nairobi, Kenya
  4. 4 Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
  5. 5 Department of Medicine, University of Washington, Seattle, Washington, USA
  6. 6 Department of Global Health, University of Washington, Seattle, Washington, USA
  1. Correspondence to Ms Erica M Lokken, Department of Epidemiology, University of Washington, Seattle, WA 98102, USA; elokken{at}


Objectives Vaginal washing has been associated with reductions in cultivable Lactobacillus and an increased risk of both bacterial vaginosis (BV) and HIV infection. The effect of vaginal washing on the quantity of individual Lactobacillus species is not well characterised. This analysis tested the hypothesis that vaginal washing would be associated with a lower likelihood of Lactobacillus spp. detected by both culture and quantitative PCR (qPCR).

Methods We conducted a cross-sectional study of 272 HIV-seronegative women enrolled in an open-cohort study in Mombasa, Kenya. Vaginal washing and sexual risk behaviours were assessed using face-to-face interviews. Vaginal Lactobacillus spp. were detected using cultivation and PCR methods, with L. crispatus, L. jensenii and L. iners concentrations measured using qPCR assays targeting the 16S rRNA gene. Poisson regression with robust SEs was used to assess associations between vaginal washing and Lactobacillus detection by culture and qPCR.

Results Eighty percent (n=217) of participants reported vaginal washing in the prior week. One-fifth (n=58) of participants had BV by Nugent score. In unadjusted analysis, vaginal washing was associated with a 45% decreased likelihood of Lactobacillus spp. detection by culture (prevalence ratio (PR): 0.55, 95% CI 0.37 to 0.82). Adjusting for age and condomless sex in the prior week did not change the magnitude of the association (adjusted PR (aPR): 0.56, 95% CI (0.37 to 0.85). Vaginal washing was associated with approximately a 40% reduction in L. crispatus detection (aPR: 0.57, 95% CI 0.36 to 0.92), but was not significantly associated with L. jensenii (aPR: 0.68, 95% CI 0.42 to 1.09) or L. iners detection (aPR: 1.03, 95% CI 0.92 to 1.15).

Conclusions Vaginal washing in the prior week was associated with a significantly reduced likelihood of detecting cultivable Lactobacillus and L. crispatus by qPCR. Given associations between Lactobacillus detection and improved reproductive health outcomes, these results provide motivation for additional study of vaginal washing cessation interventions to improve vaginal health.

  • vaginal washing
  • Lactobacillus crispatus
  • Lactobacillus jensenii
  • Lactobacillus iners
  • vaginal microbiota

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  • Handling editor Jackie A Cassell

  • Presented at This research was presented in part as a poster (#P3.059) at the 20th Meeting of the International Society for Sexually Transmitted Diseases Research (ISSTDR) held in Vienna, Austria on 14–17 July 2013.

  • Contributors JEB, RSM and DNF designed the study. JEB, EML and RSM planned the statistical analysis and EML executed the statistical analyses and drafted the manuscript. Staff training, field site supervision and/or study implementation was conducted by GOM, CN, JK, WJ, JEB and RSM. Laboratory oversight and/or testing was conducted by AA, JS, WJ, SS, TLF, MMM and DNF. All authors contributed significantly to interpreting the study results and reviewed versions of the manuscript.

  • Funding This research was funded by grants from the National Institutes of Health (R37 AI38518, P01 HD64915, EML by T32 AI07140, K24 HD88229 to RSM for mentoring). Infrastructure and logistical support for the Mombasa research site was provided by the University of Washington’s Center for AIDS Research (CFAR), an NIH-funded program (P30 AI027757) which is supported by the following research centres: NIAID, NCI, NIMH, NIDA, NICHD, NHLBI, NCCAM.

  • Disclaimer The content of this paper is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

  • Competing interests RSM receives research funding, paid to the University of Washington, from Hologic, Inc (Marlborough, Massachusetts). JEB received honoraria for consulting from Lupin Pharmaceuticals (Mumbai, India). All other authors declare they have no conflicts of interest to report.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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