Factors Associated with Acquisition of, or Persistent Colonization by, Vaginal Lactobacilli: Role of Hydrogen Peroxide Production

Abstract

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 H(2)O(2)-producing L. crispatus or L. jensenii, 23 (40%) remained colonized over 8 months, compared with 1 (5%) of 21 women colonized by other H(2)O(2)-producing species or by H(2)O(2)-negative strains (P=.01). Frequency of sexual intercourse (> or =1 sex act per week) was associated with loss of colonization with H(2)O(2)-producing lactobacilli (P=.018), as was antibiotic use (P< or =.0001). Other behavioral and demographic characteristics did not predict sustained colonization. The production of H(2)O(2) is closely linked with species and is a predictor for sustained long-term colonization of the vagina.

Identification and in vitro production of Lactobacillus antagonists from women with or without bacterial vaginosis

“…However, the same species did not exhibit this ability when recovered from patients with BV. During an 8-month study, Vallor et al (2) showed that, in contrast to L. crispatus and L. jensenii H 2 O 2 -producing isolates, strains that did not produce the antimicrobial substance were rapidly lost, a fact that supports the role of this production in sustained colonization. However, as demonstrated by diffusion assays, there is not always a direct correlation between the ability for H 2 O 2 production and the antagonistic activity of lactobacilli (24).…”

“…They play a protective role mainly by a combination of steric exclusion and the production of inhibitory substances (2). The lactobacilli metabolize glucose essentially to lactic acid, which contributes to the maintenance of a low vaginal pH (4.0-4.5) and reduces the growth of most pathogenic microorganisms.…”

Qualitative and semiquantitative analysis of Lactobacillus species in the vaginas of healthy fertile and postmenopausal Chinese women

“…For example, according to a study conducted in Sweden, the most common vaginal Lactobacillus species in Swedish women was L. crispatus (Vásquez et al, 2002), while a study in Canada showed that in Canadian women L. iners was the most prevalent (Burton et al, 2003). A study of the vaginal microbiota in America found L. jensenii to be the most frequently occurring species in the vaginas of American women (Vallor et al, 2001). Geographical separation may be one of the reasons for the varying results of these studies.…”

Biofilm and Urogenital Infections

“…As defined by Amsel clinical criteria, BV exhibits at least 3 of the following 4 clinical symptoms: 1) elevation of vaginal fluid pH to above 4.5; 2) detectable "fishy odor" of vaginal fluid upon addition of 10% potassium hydroxide; 3) presence of clue cells, vaginal epithelial cells covered with bacteria, in vaginal fluid; and 4) milky vaginal discharge. The vaginal flora of healthy women consists predominantly of Gram-positive lactobacilli, especially Lactobacillus cripatus and Lactobacillus jensenii [60][61][62]. Productions of antimicrobial proteins as well as the maintenance of acidic pH and hydrogen peroxide (H 2 O 2 ) in the vaginal fluid by these bacteria contribute critically to the establishment of a healthy ecosystem in the vagina [61][62][63].…”