Adherence of Lactobacillus crispatus to vaginal epithelial cells from women with or without a history of recurrent urinary tract infection.

PURPOSE: Lactobacillus crispatus strain CTV-05 is a vaginal probiotic proposed for use in women with recurrent urinary tract infection to reduce vaginal colonization with Escherichia coli and the risk of urinary tract infection. However, the ability of this probiotic strain to adhere to the target mucosa, vaginal epithelial cells, has not been assessed in women with recurrent urinary tract infection. We measured the adherence of L. crispatus strain CTV-05 to vaginal epithelial cells collected from more than 100 premenopausal women with (cases) and without (controls) a history of recurrent urinary tract infection. We also examined the effects of relevant host factors on bacterial adherence. MATERIALS AND METHODS: Bacterial adherence assays were performed by combining L. crispatus CTV-05 with exfoliated vaginal epithelial cells collected from 51 case women and 51 controls. RESULTS: L. crispatus CTV-05 adhered in high numbers to vaginal epithelial cells from women with recurrent urinary tract infection (mean adherence of 50.5 lactobacilli per vaginal epithelial cell) and controls (mean adherence of 39.4 lactobacilli per vaginal epithelial cell). Adherence was significantly higher using vaginal epithelial cells from women with a maternal history of urinary tract infection (p = 0.036) and a nonsecretor phenotype (p < 0.001), but was not significantly affected by recent spermicide use, oral contraceptive use, menstrual cycle phase or sexual activity. CONCLUSIONS: L. crispatus strain CTV-05 is highly adherent to vaginal epithelial cells collected from a large sample of premenopausal women with or without a history of recent recurrent urinary tract infection. These data strongly support further evaluation of this probiotic in clinical trials of women with recurrent urinary tract infection.

Precise and rapid assessment of Escherichia coli adherence to vaginal epithelial cells by flow cytometry.

BACKGROUND: In the pathogenesis of Escherichia coli urinary tract infections (UTIs) in women, infecting bacteria adhere to vaginal and periurethral epithelial cells prior to ascending to the bladder and causing infection. Complex interactions among specific bacterial adhesins and various host factors appear to influence adherence of E. coli to mucosal surfaces such as the urogenital epithelium. To conduct population-based studies assessing host epithelial cell determinants that influence bacterial attachment, a method of measuring bacterial adherence utilizing clinically derived epithelial cell samples is needed. METHODS: We developed and standardized an efficient, accurate, high-throughput method for analyzing the adherence of uropathogenic E. coli to clinical samples containing a large number of exfoliated vaginal epithelial cells (VEC). Three wild-type E. coli strains isolated from women with UTI (IA2 expressing pap-encoded, class II fimbriae only; F24 expressing pap-encoded, class II and type 1 fimbriae; and F20, without pap-encoded or type I fimbriae) were transformed with gfpmut3, encoding green fluorescent protein, incubated with VECs, and analyzed by flow cytometry. RESULTS: Enumeration of the binding of each E. coli strain to 10,000 VECs showed reproducible, highly significant strain-dependent differences in adherence to VECs. Differential analysis of the relative contributions of type 1 pili and P fimbrial-mediated binding to the adherence phenotype was performed. It demonstrated that IA2 binding was dependent entirely on P fimbriae, whereas F24 binding was dependent on both P and type 1 fimbriae. CONCLUSIONS: This method has great potential for use in high-throughput analyses of clinically derived epithelial cell samples and will be valuable in population-based investigations of host-parasite interactions in UTI utilizing VECs collected from specific patient groups.

Variation in frequency of the virulence-factor gene in Escherichia coli clones colonizing the stools and urinary tracts of healthy prepubertal girls.

To provide information on virulence expression of Escherichia coli in healthy hosts, stool, periurethral, and urine samples were collected weekly from healthy 3-6-year-old girls who lived in a small rural community. Dominant and nondominant clones were defined in stool specimens, and the expression of virulence factors was determined. We found that healthy girls commonly shared dominant clones. P adhesin, hemolysin, and type I adhesin were commonly found in clones in the stool and in clones in the urinary tract. In addition, expression of virulence factors, among both dominant and nondominant clones in the stool, changed from week to week. The presence of P adhesin was a marker for the persistence of a dominant clone in the stool and was associated with an increased likelihood that a nondominant clone would be detected in the urinary tract. Type I adhesin was ubiquitous among stool strains, with orientation of the fimbrial switch being both in the "off" position and in both the "on" and "off" positions. In summary, the intestinal flora of healthy girls is complex, with frequent changes in virulence expression.

ABO and P1 blood group antigen expression and stx genotype and outcome of childhood Escherichia coli O157:H7 infections.

P1 and ABO antigens and bacterial stx genotypes might influence the risk of developing hemolytic uremic syndrome (HUS) after Escherichia coli O157:H7 infections. We determined ABO status and P1 antigen expression in 130 infected and 17 uninfected children, and we determined the stx genotype of the infecting isolate. P1 expression was weakly and directly related to HUS risk (P=.04), but this risk did not extend to the group with the greatest P1 expression. P1 expression remained constant as HUS evolved. The ABO frequency was similar in all groups. These associations were not affected by the stx genotype. stx1(-)/stx2(+) E. coli O157:H7 strains were more commonly associated with HUS than were stx1(+)/stx2(+) strains (P=.21), and 1 child with HUS was infected with a rare stx1(+)/stx2(-) isolate. In the present study, ABO antigens and stx genotypes were not major determinants of the outcome of E. coli O157:H7 infections, and P1 expression did not protect against the development of HUS.