Can known risk factors explain racial differences in the occurrence of bacterial vaginosis?
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BACKGROUND: Black women are more likely to have bacterial vaginosis (BV) than are non-Hispanic white women. We examined whether this disparity can be explained by racial differences in known BV risk factors. METHODS: Nine hundred black and 235 white women were enrolled from five US sites. At baseline, structured interviews were conducted and vaginal swabs self-collected for Gram-stain and culture. RESULTS: Black women were more likely than white women to have BV/intermediate vaginal flora. They also were more likely to be older, have lower educational attainment and family incomes, have a history of a sexually transmitted disease, and douche. After adjustment for demographic and lifestyle factors, blacks remained at elevated risk for BV/intermediate flora (OR 2.2, 95% CI 1.5-3.1). Blacks also were more likely to have specific BV-related vaginal microflora, as well as gonococcal or chlamydial cervicitis (OR 2.2, 95% CI 1.2-3.8) after adjustment for known BV risk factors. CONCLUSION: Risk factor differences did not explain the observed racial disparity in the occurrence of BV, BV-related microflora, or gonococcal or chlamydial cervicitis. These findings highlight our limited understanding of the factors accounting for the occurrence of bacterial vaginosis and cervicitis among black and white women. (+info)
High levels of Gardnerella vaginalis detected with an oligonucleotide probe combined with elevated pH as a diagnostic indicator of bacterial vaginosis.
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We have demonstrated a new approach to diagnosing bacterial vaginosis (BV) that is based on measuring the concentration of Gardnerella vaginalis in vaginal fluid with DNA probes. G. vaginalis is virtually always present at high concentrations in women who have BV but is also detected frequently in normal women, usually at concentrations of less than 10(7) CFU/ml of vaginal fluid. Elevated vaginal pH is another sensitive indicator of BV, although it can occur in conjunction with other conditions. We have proposed that quantitative measurements of G. vaginalis using specific DNA probes can serve as a useful aid in diagnosing BV, provided the vaginal pH is above 4.5. To test this hypothesis, a group of 113 women were first evaluated for BV by the standard set of clinical signs. Vaginal washes were collected, and aliquots were analyzed by quantitative culture for the concentration of G. vaginalis. Portions of these same samples were immobilized on nylon filters, along with standards for quantitation. The filters were incubated with a radiolabelled oligonucleotide specific for G. vaginalis 16S rRNA, and the subsequent autoradiographs were examined to determine levels of G. vaginalis in each sample. G. vaginalis at concentrations of greater than or equal to 2 x 10(7) CFU/ml and vaginal pH of greater than 4.5 were then analyzed for concurrence with the diagnoses based on clinical criteria. Results of this slot blot analysis gave a sensitivity of 95%, correctly categorizing 41 of 43 BV-positive specimens, and a specificity of 99%, correctly identifying 69 of 70 BV-negative specimens, compared with diagnosis based on clinical criteria. (+info)
Gardnerella vaginalis: characteristics, clinical considerations, and controversies.
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The clinical significance, Gram stain reaction, and genus affiliation of Gardnerella vaginalis have been controversial since Gardner and Dukes described the organism as the cause of "nonspecific vaginitis," a common disease of women which is now called bacterial vaginosis. The organism was named G. vaginalis when taxonomic studies showed that it was unrelated to bacteria in various genera including Haemophilus and Corynebacterium. Electron microscopy and chemical analyses have elucidated the organism's gram-variable reaction. Controversy over the etiology of bacterial vaginosis was largely resolved by (i) studies using improved media and methods for the isolation and identification of bacteria in vaginal fluids and (ii) standardization of criteria for clinical and laboratory diagnosis. Besides G. vaginalis, Mobiluncus spp., Mycoplasma hominis, and certain obligate anaerobes are now acknowledged as participants in bacterial vaginosis. The finding that G. vaginalis, Mobiluncus spp., and M. hominis inhabit the rectum indicates a potential source of autoinfection in addition to sexual transmission. Extravaginal infections with G. vaginalis are increasingly recognized, especially when the toxic anticoagulant polyanetholesulfonate is omitted from blood cultures and when urine cultures are incubated anaerobically for 48 h. The finding that mares harbor G. vaginalis suggests that an equine model can be developed for studies of Gardnerella pathogenesis. (+info)
Bacterial vaginosis: comparison of Pap smear and microbiological test results.
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Our purpose was to determine the reliability of the Pap smear in making the diagnosis of bacterial vaginosis and to examine the characteristics of Pap smear vs vaginal culture in diagnosis of bacterial vaginosis, with the vaginal Gram stain used as the diagnostic standard. We performed a prospective, blinded study involving 245 women who referred to the Department of Gynecology and Obstetrics in our hospital for routine genital examination between September 2001 and September 2002. Exclusion criteria included vaginal bleeding and pregnancy. Each patient had standard Pap smear, Gram-stained vaginal smear and culture of vaginal swab. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic value of Pap smear and vaginal culture results were determined with Gram stain used as the standard for diagnosis of bacterial vaginosis. Using Gram stain diagnosis of bacterial vaginosis as the standard, Pap smear and vaginal culture test results had sensitivity of 43.1 and 77.8%, specificity of 93.6 and 97.7%, positive predictive value of 73.8 and 93.3%, negative predictive value of 79.8 and 91.4%, diagnostic value of 78.8 and 91.8%, respectively, for the diagnosis of bacterial vaginosis. Compared to the microbiological test results, Pap smear is not sensitive enough for screening of bacterial vaginosis. However, because of its high specificity, it may be an adequate diagnostic criteria when it is positive. (+info)
Cloning of 16S rRNA genes amplified from normal and disturbed vaginal microflora suggests a strong association between Atopobium vaginae, Gardnerella vaginalis and bacterial vaginosis.
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BACKGROUND: The pathogenesis of bacterial vaginosis remains largely elusive, although some microorganisms, including Gardnerella vaginalis, are suspected of playing a role in the etiology of this disorder. Recently culture-independent analysis of microbial ecosystems has proven its efficacy in characterizing the diversity of bacterial populations. Here, we report on the results obtained by combining culture and PCR-based methods to characterize the normal and disturbed vaginal microflora. RESULTS: A total of 150 vaginal swab samples from healthy women (115 pregnant and 35 non-pregnant) were categorized on the basis of Gram stain of direct smear as grade I (n = 112), grade II (n = 26), grade III (n = 9) or grade IV (n = 3). The composition of the vaginal microbial community of eight of these vaginal swabs (three grade I, two grade II and three grade III), all from non-pregnant women, were studied by culture and by cloning of the 16S rRNA genes obtained after direct amplification. Forty-six cultured isolates were identified by tDNA-PCR, 854 cloned 16S rRNA gene fragments were analysed of which 156 by sequencing, yielding a total of 38 species, including 9 presumptively novel species with at least five species that have not been isolated previously from vaginal samples. Interestingly, cloning revealed that Atopobium vaginae was abundant in four out of the five non-grade I specimens. Finally, species specific PCR for A. vaginae and Gardnerella vaginalis pointed to a statistically significant co-occurrence of both species in the bacterial vaginosis samples. CONCLUSIONS: Although historically the literature regarding bacterial vaginosis has largely focused on G. vaginalis in particular, several findings of this study--like the abundance of A. vaginae in disturbed vaginal microflora and the presence of several novel species--indicate that much is to be learned about the composition of the vaginal microflora and its relation to the etiology of BV. (+info)
Clinical evaluation of affirm VPIII in the detection and identification of Trichomonas vaginalis, Gardnerella vaginalis, and Candida species in vaginitis/vaginosis.
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OBJECTIVE: To compare the Affirm VPIII Microbial Identification Test for detection and identification of Candida species, Gardnerella vaginalis and Trichomonas vaginalis to clinical and microscopic criteria commonly used to diagnose vaginitis. METHODS: Women that were symptomatic for vaginitis/vaginosis and asymptomatic women being seen for routine obstetric or gynecological care were included in this study. Women treated with antibiotics or antifungals within one week or women who had douched within 24 hours were excluded. Two vaginal swab specimens were simultaneously obtained from each patient, one swab was placed in sterile physiological saline for immediate microscopic wet mount examination and KOH testing. The other swab was placed in the Affirm collection tube for Affirm VPIII testing based on previously demonstrated methods. RESULTS: The Affirm assay was significantly more likely to identify Gardnerella and Candida than wet mount. 190 (45%) were positive for Gardnerella by Affirm compared to 58 (14%) by wet mount; 45 (11%) were positive for Candida by Affirm compared to 31 (7%) by wet mount; and 30 (7%) were positive for Trichomonas by Affirm compared to 23 (5%) by wet mount. Symptomatic women were significantly more likely to be positive by Affirm only (23% vs. 10%), wet mount only (3% vs. 2%) or Affirm and wet mount (15% vs. 1%). Asymptomatic women were significantly more likely to be negative for Affirm and wet mount (43% vs. 5%). CONCLUSIONS: The Affirm VPIII test is a more sensitive diagnostic test for detection and identification of symptomatic vaginitis/vaginosis than conventional clinical examination and wet mount testing. (+info)
Female genital-tract HIV load correlates inversely with Lactobacillus species but positively with bacterial vaginosis and Mycoplasma hominis.
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BACKGROUND: Bacterial vaginosis (BV) is associated with human immunodeficiency virus (HIV) acquisition. We examined the association between BV and BV-associated bacteria and expression of HIV in the female genital tract. METHODS: HIV RNA, lactobacilli, Gardnerella vaginalis, and Mycoplasma hominis in cervicovaginal lavage (CVL) samples were quantified by polymerase chain reaction (PCR). Gynecologic evaluation included Nugent score assessment, Amsel criteria assessment, detection of other genital-tract infections, and dysplasia grading. CD4 cell count, plasma HIV RNA level, and antiretroviral history were obtained. RESULTS: A total of 203 CVL samples from women with Nugent scores of 7-10 (BV group) and 203 samples from women with Nugent scores of 0-3 (no-BV group) were matched by plasma HIV RNA level and analyzed. After controlling for plasma HIV RNA level and Nugent score in univariate analyses, we found that G. vaginalis and M. hominis bacterial counts, Candida vaginitis, and herpes simplex virus (HSV) were positively associated with CVL HIV RNA levels. In multivariate analysis, only lactobacilli bacterial counts (P=.006; inverse association), M. hominis bacterial counts (P=.0001; positive association), Candida vaginitis (P=.007), and HSV (P=.03) were significantly associated with CVL HIV RNA levels. CONCLUSION: Bacteria associated with BV increase genital-tract HIV RNA levels. Quantitative bacterial counts for lactobacilli and M. hominis are better correlates of CVL HIV RNA than are Nugent score or Amsel criteria. Since plasma virus and CD4 cell levels did not differ between the BV and no-BV groups, these data suggest that the bacterial flora associated with BV influence genital-tract HIV shedding. (+info)
Vaginal flora morphotypic profiles and assessment of bacterial vaginosis in women at risk for HIV infection.
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Specific morphotypic profiles of normal and abnormal vaginal flora, including bacterial vaginosis (BV), were characterized. A prospective study of 350 women yielded concurrent Gram-stain data and clinical assessment (n = 3455 visits). Microbiological profiles were constructed by Gram stain. Eight profile definitions were based on dichotomizing the levels of Lactobacillus, Gardnerella, and curved, Gram-negative bacillus (Mobiluncus) morphotypes. Of these, two were rare, and the other six demonstrated a graded association with the clinical components of BV. The proposed profiles from the Gram stain reflect the morphotypic categories describing vaginal flora that may enable clearer elucidation of gynecologic and obstetric outcomes in various populations. (+info)