title: Effect of sexual activity on vaginal colonization with hydrogen peroxide-producing lactobacilli and Gardnerella vaginalis.
abstract: BACKGROUND
  Bacterial vaginosis is associated with sexual activity, but mechanisms for this association are unclear.
  
  
  METHODS
  Cross-sectional analysis of data from women reporting sex with women who provided information on sexual behaviors as part of a study of vaginal bacteria was conducted. Vaginal bacteria were detected by semiquantitative culture. Binomial regression with log-link evaluated associations between detection of bacteria and sexual behaviors reported to occur before enrollment. Linear regression evaluated associations between these behaviors and quantity of bacteria.
  
  
  RESULTS
  Of the 320 women, 216 (68%) were colonized with H2O2-producing lactobacilli and 142 (44%) with Gardnerella vaginalis. Colonization with G. vaginalis was associated with >20 digital-vaginal sex acts (risk ratio, 2.01; 1.22, 3.29) or >10 toy-vaginal acts in the past 3 months (risk ratio, 1.76; 1.32, 2.36). Quantity of H2O2-producing lactobacilli was 1.3 log lower in colonized women reporting >10 acts of insertive vaginal sex-toy use in the past 3 months (95% confidence interval: -2.04, -0.56), 1.19 log lower with toy-vaginal sex in past 7 days (-1.75, -0.62), and 0.78 log lower in women sharing toys with a partner (-1.25, -0.31).
  
  
  CONCLUSIONS
  Vaginal insertive use and sharing of sex toys were associated with decreased quantities of H2O2-producing lactobacilli and higher risk of colonization with G. vaginalis.
authors.affiliation: Department of Obstetrics & Gynecology, University of Washington, Seattle, WA 98195, USA. camitch@uw.edu
authors.forename: Caroline
authors.initials: C
authors.lastname: Mitchell
authors.forename: Lisa E
authors.initials: LE
authors.lastname: Manhart
authors.forename: Katherine K
authors.initials: KK
authors.lastname: Thomas
authors.forename: Kathy
authors.initials: K
authors.lastname: Agnew
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: Marrazzo
mesh_terms: D000328:Adult; D058491:Bacterial Load; D003470:Culture Media; D005260:Female; D006194:Gardnerella vaginalis / Q000254:growth & development* / Q000302:isolation & purification; D018452:Homosexuality, Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007778:Lactobacillus / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D012725:Sexual Behavior / Q000502:physiology*; D014621:Vagina / Q000382:microbiology*; D016585:Vaginosis, Bacterial / Q000382:microbiology*; D055815:Young Adult
chemical_list: D003470:Culture Media; D006861:Hydrogen Peroxide
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