Factors associated with acquisition of, or persistent colonization by, vaginal lactobacilli: Role of hydrogen peroxide production

To identify factors that predict sustained colonization by vaginal lactobacilli, microbiologic, behavioral, and demographic data were obtained from 101 nonpregnant women at baseline and at 4 and 8 months. A total of 272 isolates of lactobacilli were identified to the species level by use of whole chromosomal DNA homology to type strains. The predominant lactobacilli were the species Lactobacillus crispatus (38%) and L. jensenii (41%). Of 57 women initially colonized by H2O2-producing L. crispatus or L. jensenii, 23 (40%) remained colonized over 8 months, compared with 1 (5%) of 21 women colonized by other H2O2-producing species or by H2O2-negative strains (P = .01). Frequency of sexual intercourse ( 1 sex act per week) was associated with loss of colonization with H2O2-producing lactobacilli (P = .018), as was antibiotic use (P less than or equal to .0001). Other behavioral and demographic characteristics did not predict sustained colonization. The production of H2O2 is closely linked with species and is a predictor for sustained long-term colonization of the vagina.