Streptococcus Vaginal Colonization Research Articles

Performances of two rapid LAMP-based techniques for the intrapartum detection of Group B Streptococcus vaginal colonization

PurposeGroup B Streptococcus (GBS) is the leading cause of invasive infections in newborns. The prevention of GBS neonatal disease relies on the administration of an intrapartum antibiotic prophylaxis to GBS-colonized women. In recent years, rapid intrapartum detection of GBS vaginal colonization using real-time nucleic acid amplification tests (NAATs) emerged as an alternative to antenatal culture screening methods.MethodsWe compared the performances of two loop-mediated isothermal amplification (LAMP) tests, the Ampliflash® GBS and the PlusLife® GBS tests, to standard culture for GBS detection in vaginal specimens from pregnant women. The study was conducted from April to July 2023 in a French hospital of the Paris area.ResultsA total of 303 samples were analyzed, including 85 culture-positive samples (28.1%). The Ampliflash® GBS test and the PlusLife® GBS tests gave a result for 100% and 96.3% tests, respectively. The performances of the tests were as follows: sensitivity 87.1% (95% confidence interval (CI) 78.3–92.6) and 98.7% (95% CI 93.0-99.8), specificity 99.1% (95% CI 96.7–99.8), and 91.9% (95% CI 87.3–95.0), respectively. False negative results of the Ampliflash® GBS test correlated with low-density GBS cultures. Time-to-results correlated with GBS culture density only for the PlusLife® GBS test (p < 0.001).ConclusionBoth techniques provide excellent analytical performances with high sensitivity and specificity together with a short turnaround time and results available in 10 to 35 min. Their potential to further reduce the burden of GBS neonatal disease compared with antenatal culture screening needs to be assessed in future clinical studies.

Group B Streptococcus vaginal colonization in pregnant women living with HIV infection: prevalence and antibiotic susceptibility at HIV referral centers in Lagos, Nigeria

Objectives Group B Streptococcus (GBS) colonization of the genital tract is often asymptomatic yet associated with increased risks of maternal and neonatal morbidity especially amongst women living with HIV infection. The objectives of this study were to determine the prevalence of GBS colonization of the genital tract in women living with HIV infection and antibiotic susceptibility of GBS in the genital tract. Method This cross-sectional study recruited 244 pregnant women (122 women living with HIV infection and 122 HIV-uninfected women) between 35 and 37 weeks of gestation. GBS colonization was determined by collecting lower vaginal and anal swabs at recruitment. Swabs were cultured in Todd Hewitt’s broth and confirmed by Christie, Atkins, and Munch-Peterson (CAMP) test. Most recent CD4 count and viral load estimates were retrieved from the women’s records. Maternal and neonatal outcomes and antibiotic susceptibility were assessed. Statistical analysis was performed at 95% confidence interval at a statistical significance of p < .005 Results The prevalence of GBS colonization of the genital tract in all participants was 3.3%; GBS was isolated in 4 (3.3%) of 122 pregnant women living with HIV. No woman with a GBS-colonized genital tract developed puerperal sepsis and no neonatal infection occurred in neonates born to GBS-positive women, irrespective of HIV infection status. In women living with HIV, GBS isolate was resistant to Ampicillin (100%), Ceftriaxone (100%), Vancomycin (100%), yet partially sensitive to Ciprofloxacin (50%). Conclusion Pregnant women living with HIV do not have an increased risk of genital GBS colonization. Vaginal GBS colonization was not associated with an adverse perinatal outcome. Antibiotic use for GBS colonization should be based on sensitivity pattern and not empiric.

Gardnerella vaginalis promotes group B Streptococcus vaginal colonization, enabling ascending uteroplacental infection in pregnant mice

Group B Streptococcus is a common vaginal bacterium and the leading cause of invasive fetoplacental infections. Group B Streptococcus in the vagina can invade through the cervix to cause ascending uteroplacental infections or can be transmitted to the neonate during vaginal delivery. Some studies have found that women with a "dysbiotic" polymicrobial or Lactobacillus-depleted vaginal microbiota aremore likely to harbor group B Streptococcus. Gardnerella vaginalis is often the most abundant bacteria in the vaginas of women with dysbiosis, while being detected at lower levels in most other women, and has been linked with several adverse pregnancy outcomes. Mouse models of group B Streptococcus and Gardnerella vaginalis colonization have been reported but, to the best of our knowledge, the two have not been studied together. The overarching idea driving this study is that certain members of the dysbiotic vaginal microbiota, such as Gardnerella vaginalis, may directly contribute to the increased rate of group B Streptococcus vaginal colonization observed in women with vaginal dysbiosis. We used a mouse model to test the hypothesis that vaginal exposure to Gardnerella vaginalis may facilitate colonization and/or invasive infection of the upper reproductive tract by group B Streptococcus during pregnancy. Timed-pregnant mice were generated using an allogeneic mating strategy with BALB/c males and C57Bl/6 females. Dams were vaginally inoculated at gestational day 14 with group B Streptococcus alone (using a 10-fold lower dose than previously reported models) or coinoculated with group B Streptococcus and Gardnerella vaginalis. Bacterial titers were enumerated in vaginal, uterine horn, and placental tissues at gestational day 17. The presence (Fisher exact tests) and levels (Mann-Whitney U tests) of bacterial titers were compared between mono- and coinoculated dams in each compartment. Relative risks were calculated for outcomes that occurred in both groups. Tissue samples were also examined for evidence of pathophysiology. Inoculation of pregnant mice with 107 group B Streptococcus alone did not result in vaginal colonization or ascending infection. In contrast, coinoculation of group B Streptococcus with Gardnerella vaginalis in pregnant mice resulted in a 10-fold higher risk of group B Streptococcus vaginal colonization (relative risk, 10.31; 95% confidence interval, 2.710-59.04; P=.0006 [Fisher exact test]). Ascending group B Streptococcus infection of the uterus and placenta occurred in approximately 40% of coinoculated animals, whereas none of those receiving group B Streptococcus alone developed uterine or placental infections. Immunofluorescence microscopy revealed group B Streptococcus in both the maternal and fetal sides of the placenta. Histologic inflammation and increased proinflammatory cytokines were evident in the setting of group B Streptococcus placental infection. Interestingly, placentas from dams exposed to group B Streptococcus and Gardnerella vaginalis, but without recoverable vaginal or placental bacteria, displayed distinct histopathologic features and cytokine signatures. These data suggest that Gardnerella vaginalis vaginal exposure can promote group B Streptococcus vaginal colonization, resulting in a greater likelihood of invasive perinatal group B Streptococcus infections. These findings suggest that future clinical studies should examine whether the presence of Gardnerella vaginalis is a risk factor for group B Streptococcus vaginal colonization in women. Because Gardnerella vaginalis can also be present in women without bacterial vaginosis, these findings may be relevant both inside and outside of the context of vaginal dysbiosis.

Persistence of group B Streptococcus vaginal colonization and prevalence of hypervirulent CC-17 clone correlate with the country of birth: a prospective 3-month follow-up cohort study.

To identify factors associated with vaginal colonization and persistence by group B Streptococcus (GBS) and by the hypervirulent neonatal CC-17 clone in late pregnancy and after delivery, a multicentre prospective observational cohort with 3-month follow-up was established in two university hospitals, Paris area, France. Pregnant women were recruited when antenatal screening for GBS vaginal colonization at 34-38weeks of gestational age was positive. Vaginal samples were analysed by conventional culture methods at antenatal screening, delivery, and 21 and 60days following delivery. Identification of the hypervirulent neonatal GBS CC-17 was performed. Colonization was defined as persistent when all vaginal samples were positive for GBS. A total of 754 women were included. GBS vaginal colonization was persistent in 63% of the cases (95% CI 59%-67%). Persistent colonization was more likely in women born in Sub-Saharan Africa compared with women born in France (OR = 1.88, 95% CI 1.05-3.52), and GBS CC-17 was overrepresented in women born in Sub-Saharan Africa (OR = 2.09, 95% CI 1.20-3.57). Women born in Sub-Saharan Africa are at higher risk for GBS vaginal persistence than women born in France. This observation correlates with an increased prevalence of the hypervirulent GBS CC-17 in the former group, which likely reflect variations linked to ethnicity and vaginal community-state types and might account for the increased susceptibility of black neonates to GBS infections.

Cellular immune response induced by surface immunogenic protein with AbISCO-100 adjuvant vaccination decreases group B Streptococcus vaginal colonization

Group B Streptococcus (GBS) represents one of the most common causes of bacterial infection in neonates; it is also associated with premature childbirth and stillbirth. A vaccine against GBS is needed, but no approved vaccines are yet available. The Surface Immunogenic Protein (SIP) of GBS is conserved in all serotypes and had been reported to be a good vaccine prototype in a mouse model of GBS infection. Also, we have previously shown that both subcutaneous and oral immunization with rSIP can induce an efficient immune response that decreases GBS vaginal colonization in mice. In this study, we show that a vaccine based on a mixture of rSIP and AbISCO-100 adjuvant reduces GBS vaginal colonization in mice and induces antibodies with opsonophagocytic activities. Moreover, the passive transfer of sera and total T-cells from mice immunized with rSIP mixed with AbISCO-100 to unvaccinated mice decreases vaginal GBS colonization in an infected mouse. This is the first report of cellular immunity associated with rSIP-based vaccine testing in a mouse model of GBS infection.

Preventive effect of Lactobacillus reuteri CRL1324 on Group B Streptococcus vaginal colonization in an experimental mouse model.

To assess the preventive effect of different intravaginal (i.va.) doses of Lactobacillus reuteri CRL1324 against vaginal colonization by Group B Streptococcus (GBS) in a murine experimental model. The major virulence factors of four vaginal GBS clinical isolates were determined to select the most virulent strain and set up a murine model of streptococcal vaginal colonization. Later, the effect of four and seven doses of 10(8) viable cells of Lact.reuteri CRL1324 i.va. administered, prior to the GBS challenge was studied. Seven doses of lactobacilli were able to significantly reduce the number of viable GBS cells, while four doses showed no preventive effect. Both doses reduced the leucocyte influx induced by GBS. Seven doses caused a slight increase in the Lact.reuteri CRL1324 vaginal colonization compared with four doses and reduced murine vaginal pH compared to control mice. Lactobacillus reuteri CRL1324 evidenced a preventive effect on GBS vaginal colonization in an experimental mouse model. Maternal GBS colonization is one of the most important risk factors for developing disease in newborns. Lactobacillus reuteri CRL1324 could be considered as a new biological agent to reduce infections caused by this micro-organism.

Effects of Probiotic Use During Pregnancy on Lactobacillus and Group B Streptococcus Vaginal Colonization: Pilot Results

Journal of Midwifery & Women's HealthVolume 57, Issue 5 p. 537-537 American College of Nurse-Midwives Annual Meeting Effects of Probiotic Use During Pregnancy on Lactobacillus and Group B Streptococcus Vaginal Colonization: Pilot Results First published: 06 September 2012 https://doi.org/10.1111/j.1542-2011.2012.00223.xCitations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume57, Issue5September/October 2012Pages 537-537 ACNM Members ACNM Members: Click here to log in RelatedInformation

Comparative evaluation of Strepto B ID®chromogenic medium and Granada media for the detection of Group B streptococcus from vaginal samples of pregnant women

Two types of selective media, the chromogenic medium Strepto B ID® and two non-chromogenic media Strepto B agar® and the Granada® medium, were tested and compared to blood agar plates (BAP) for screening of Group B streptococcus vaginal colonization in pregnant women. All tested media were comparable in terms of sensitivity however, their use in routine laboratories may markedly facilitate the rapid detection of GBS in vaginal samples.

Uterine side effects of tamoxifen: a need for systematic pretreatment screening

To evaluate the relationship between the time elapsed from the administration of ampicillin prophylaxis to delivery and its efficacy in interrupting intrapartum transmission of group B streptococcus. During the 12-month study period, all women who came to the Virgen de las Nieves Hospital (Granada, Spain) for delivery were screened for group B streptococcus vaginal carriage by a pigment-detection culture-based procedure. Colonized women were treated with ampicillin (2 g intravenously), and the interval between ampicillin administration and delivery was recorded. Newborns from colonized mothers also were screened to detect group B streptococcus colonization. During the study period, 4525 women were admitted to the hospital for delivery and screened for group B streptococcus vaginal colonization. Group B streptococcus was detected in 543 women (12%), of whom 454 gave birth vaginally to 454 liveborn infants. Intrapartum ampicillin was given to 201 of these 454 women (44%), and 10% of the newborns from mothers who received intrapartum ampicillin prophylaxis were colonized by group B streptococcus. The relationship between timing of ampicillin administration and rate of neonatal group B streptococcal transmission was as follows: less than 1 hour before delivery, 46%; 1-2 hours, 29%; 2-4 hours, 2.9%; and more than 4 hours, 1.2%. Among the 253 mothers who received no intrapartum prophylaxis, colonization was found in 120 of their newborns (47%). When the time between the start of ampicillin prophylaxis and delivery is at least 2 hours, vertical transmission of group B streptococcus is minimized.

Prevalence of type-specific group B streptococcal antibody in human sera: A study of 405 pregnant women

Presence of immunoglobulin G antibody against the five standard serotypes of group B streptococcus was measured by means of indirect immunofluorescence in the sera of 405 women at the time of delivery in the obstetric hospital in Vancouver. Antibody to all five serotypes was present in 22% of women whereas only 9.6% had no detectable antibody to any serotype. Among 47 women with group B streptococcus vaginal colonization, IgG antibody was detected against the homologous colonizing serotype in 100%, 75%, 78%, 89%, and 100% of sera for serotypes Ia, Ib, Ic, II, and III, respectively. This contrasted with the women who had heterologous group B streptococcal vaginal colonization or no colonization in whom 71% had serum IgG antibody to serotype Ia, 36% to Ib, 51% to Ic, 66% to II, and 60% to III. Overall the serum antibody titers were low, and few women had titers greater than 1:20 for any of the five standard serotypes.