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 lactobac illi, microbiologic, behavioral, and demographic data were obtained from 10 1 nonpregnant women at baseline and at 4 and 8 months. A total of 272 isola tes of lactobacilli were identified to the species level by use of whole ch romosomal DNA homology to type strains. The predominant lactobacilli were t he 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 coloni zed by other H2O2-producing species or by H2O2-negative strains (P = .01). Frequency of sexual intercourse ( 1 sex act per week) was associated with l oss of colonization with H2O2-producing lactobacilli (P = .018), as was ant ibiotic use (P less than or equal to .0001). Other behavioral and demograph ic characteristics did not predict sustained colonization. The production o f H2O2 is closely linked with species and is a predictor for sustained long -term colonization of the vagina.