Group B streptococci colonization in pregnant women: Risk factors and evaluation of the vaginal flora
Department of Pathology, Botucatu Medical School, São Paulo State University, UNESP, Distrito de Rubião Júnior, Botucatu, São Paulo 18618-970, Brazil. Archives of Gynecology
(Impact Factor: 1.36).
03/2010; 283(4):717-21. DOI: 10.1007/s00404-010-1439-8
To determine the prevalence of group B streptococci (GBS) in our population, and to assess the association between risk factors and vaginal flora with maternal rectovaginal colonization.
Samples were obtained from 405 patients between 35 and 37 weeks of gestation. Swabs from the vaginal and perianal regions were cultured in Todd Hewitt and subcultured in blood agar. Colonies suggestive of GBS were submitted to catalase and CAMP test. The vaginal flora was evaluated on Gram stain vaginal smears. Socio-demographic and obstetric data were obtained by designed form. Considering maternal GBS colonization as the response variable, a logistic regression model was fitted by the stepwise method with quantitative and qualitative explanatory variables.
The prevalence of GBS colonization was 25.4%. The most frequent vaginal flora abnormalities were cytolytic vaginosis (11.3%), followed by bacterial vaginosis (10.9%), candidosis (8.2%) and intermediate vaginal flora II (8.1%). Logistic regression analysis revealed that maternal age, number of sexual intercourse/week, occurrence of previous spontaneous abortion, presence of candidosis and cytolytic vaginosis were associated with streptococcal colonization.
The prevalence of GBS is high in pregnant women and is associated with sexual intercourse frequency, previous spontaneous abortion and the presence of candidosis or cytolytic vaginosis.
Available from: journals.plos.org
- "The latter finding is in accordance a study of Hillier and coworkers, reporting a significant negative association between GBS carriage and BV by Nugent scoring, studying 7,918 pregnant women. Two other studies did not confirm these findings[94,109]. In depth analysis of abovementioned interdependencies of GBS, E. coli, C. albicans, BV and the vaginal microbiome will be published elsewhere. "
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One million neonates die each year in low- and middle-income countries because of neonatal sepsis; group B Streptococcus (GBS) and Escherichia coli are the leading causes. In sub-Saharan Africa, epidemiological data on vaginal GBS and E. coli carriage, a prerequisite for GBS and E. coli neonatal sepsis, respectively, are scarce but necessary to design and implement prevention strategies. Therefore, we assessed vaginal GBS and E. coli carriage rates and risk factors and the GBS serotype distribution in three sub-Saharan countries.
A total of 430 women from Kenya, Rwanda and South Africa were studied cross-sectionally. Vaginal carriage of GBS and E. coli, and GBS serotype were assessed using molecular techniques. Risk factors for carriage were identified using multivariable logistic regression analysis.
Vaginal carriage rates in reference groups from Kenya and South Africa were 20.2% (95% CI, 13.7-28.7%) and 23.1% (95% CI, 16.2-31.9%), respectively for GBS; and 25.0% (95% CI, 17.8-33.9%) and 27.1% (95% CI, 19.6-36.2%), respectively for E. coli. GBS serotypes Ia (36.8%), V (26.3%) and III (14.0%) were most prevalent. Factors independently associated with GBS and E. coli carriage were Candida albicans, an intermediate vaginal microbiome, bacterial vaginosis, recent vaginal intercourse, vaginal washing, cervical ectopy and working as a sex worker. GBS and E. coli carriage were positively associated.
Reduced vaginal GBS carriage rates might be accomplished by advocating behavioral changes such as abstinence from sexual intercourse and by avoidance of vaginal washing during late pregnancy. It might be advisable to explore the inclusion of vaginal carriage of C. albicans, GBS, E. coli and of the presence of cervical ectopy in a risk- and/or screening-based administration of antibiotic prophylaxis. Current phase II GBS vaccines (a trivalent vaccine targeting serotypes Ia, Ib, and III, and a conjugate vaccine targeting serotype III) would not protect the majority of women against carriage in our study population.
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ABSTRACT: Today, ultra-high throughput screening (uHTS) methods enable screening of 100,000 samples/day or more to meet the demands for speed, with assay volumes miniaturised to 10 μl or below to reduce reagent consumption. Various methods have been employed and are now implemented on a common instrumental platform (EVOscreen™ by Evotec Technologies, Hamburg), which allows efficient selection of the best read-out mode for particular assay types, or even multiplexing of methods. Fluorescence correlation spectroscopy (PCS) is sensitive to changes in diffusion as seen when a fluorescent ligand binds to a receptor protein, for example. Fluorescence intensity distribution analysis (FIDA) allows detection of changes in specific brightness which could be caused for example by quenching, fluorescence resonance energy transfer (FRET) or accumulation of fluorophores on particles with multiple binding sites. By extending this method to 2-channel detection (2D-FIDA) using a polarising beamsplitter, anisotropy changes can be monitored, which is often the method of choice for small-ligand binding assays. Finally, using pulsed laser sources and single-photon counting electronics, fluorescence lifetimes can be measured providing a robust read-out parameter in various assay formats. We will present examples of assays and screens based on these detection modes which include the most important target classes and cover a variety of assay types. Several examples for these assay types and their validation for uHTS will be discussed.
Available from: ncbi.nlm.nih.gov
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ABSTRACT: Our understanding of the bacterial species inhabiting the female genital tract has been limited primarily by our ability to detect them. Early investigations using microscopy and culture-based techniques identified lactobacilli as the predominant members of the vaginal microbiota and suggested that these organisms might serve a protective function at the mucosal surface. Improvements in cultivation techniques and the development of molecular-based detection strategies validated these early findings and enabled us to recognize that the microbiota of the female genital tract is much more complex than previously suspected. Disruption of the vaginal microbial community due to invasion of exogenous organisms or by overgrowth of one or more endogenous species has important health implications for both the mother and newborn.
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