Intrapartum Group B Streptococcus Research Articles

Exploring the Feasibility of Intrapartum GBS Collection to Identify Residual GBS in a Pilot Study of an Antenatal Probiotic Intervention

(1) Background: We aimed to explore the feasibility of collecting intrapartum maternal Group B Streptococcus (GBS) colonization and immediate post-birth neonatal GBS colonization cultures for use in a larger trial and to identify cases of residual GBS, which were hypothesized to be less common in the probiotics group. (2) Methods: This sub-study added additional outcome measures to the parent study to identify intrapartum and neonatal colonization and compare between probiotic and placebo groups and to identify cases of residual GBS. Intrapartum maternal vaginal and rectal GBS cultures were collected at the time of admission to a hospital for labor and to give birth. Neonatal oral and nasopharynx GBS cultures were collected within 1–2 h of giving birth. (3) Results: Thirty intrapartum samples were collected; twenty-eight had complete data. The antepartum GBS results significantly predicted the intrapartum results (p = 0.005), with 86.7% of cultures remaining the same at both time points. There were four cases where the intrapartum GBS results were different to the 36-week antepartum cultures results. A case of residual GBS was identified in one probiotic group participant. None of the neonatal swabs were positive for GBS. No cases of EOGBSD occurred in infants born to the study participants. (4) Conclusions: Although the 36–37 week GBS results significantly predicted the intrapartum results, the utility for a larger research trial on probiotics to reduce antenatal GBS is unclear. Intrapartum GBS swab collection was feasible in a busy nurse, midwife, and physician practice. GBS was not recovered from neonatal oral and nasopharyngeal swabs. The pathways of neonatal GBS colonization require further study.

A cohort study of intrapartum group B streptococcus prophylaxis on atopic dermatitis in 2-year-old children

ObjectiveTo understand the occurrence of atopic dermatitis (AD) in children aged 2 years on exposure to maternal group B streptococcus (GBS) antibiotic prophylaxis (IAP).DesignRetrospective cohort study of 2909 mother–child pairs.SettingTaixing People’s Hospital in Eastern China.ParticipantsTerm infants born 2018–2019, followed longitudinally from birth to 2 years.ExposuresThe GBS-IAP was defined as therapy with intravenous penicillin G or ampicillin or cefazolin ≥ 4 h prior to delivery to the mother. Reference infants were defined as born without or with other intrapartum antibiotic exposure.OutcomesThe logistic regression models were employed to analyze the effect of intrapartum GBS prophylaxis on AD in 2-year-old children during delivery. Analysis was a priori stratified according to the mode of delivery and adjusted for relevant covariates.ResultsThe cohorts showed that preventive GBS-IAP was potentially associated with increased incidence of AD in children delivered vaginally according to logistic regression models before and after covariate-adjusted treatment (OR: 6.719,95% CI: 4.730–9.544,P < 0.001;aOR: 6.562,95% CI: 4.302–10.008, P < 0.001).ConclusionProphylactic treatment of intrapartum GBS may raise the risk of AD in vaginally delivered children. These findings highlight the need to better understand the risk between childhood AD and current GBS-IAP intervention strategies.

Intrapartum Group B Streptococcal Prophylaxis and Childhood Allergic Disorders.

To determine if maternal intrapartum group B Streptococcus (GBS) antibiotic prophylaxis is associated with increased risk of childhood asthma, eczema, food allergy, or allergic rhinitis. Retrospective cohort study of 14 046 children. GBS prophylaxis was defined as administration of intravenous penicillin, ampicillin, cefazolin, clindamycin, or vancomycin to the mother, ≥4 hours before delivery. Composite primary outcome was asthma, eczema, or food allergy diagnosis within 5 years of age, identified by diagnosis codes and appropriate medication prescription. Allergic rhinitis was defined by using diagnostic codes only and analyzed as a separate outcome. Analysis was a priori stratified by delivery mode and conducted by using Cox proportional hazards model adjusted for multiple confounders and covariates. Secondary analyses, restricted to children retained in cohort at 5 years' age, were conducted by using multivariate logistic regression. GBS prophylaxis was not associated with increased incidence of composite outcome among infants delivered vaginally (hazard ratio: 1.13, 95% confidence interval [CI]: 0.95-1.33) or by cesarean delivery (hazard ratio: 1.08, 95% CI: 0.88-1.32). At 5 years of age, among 10 404 children retained in the study, GBS prophylaxis was not associated with the composite outcome in vaginal (odds ratio: 1.21, 95% CI: 0.96-1.52) or cesarean delivery (odds ratio: 1.17, 95% CI: 0.88-1.56) cohorts. Outcomes of asthma, eczema, food allergy, separately, and allergic rhinitis were also not associated with GBS prophylaxis. Intrapartum GBS prophylaxis was not associated with subsequent diagnosis of asthma, eczema, food allergy, or allergic rhinitis in the first 5 years of age.

Vancomycin during delivery hospitalizations for women with group B streptococcus

Objective Vancomycin use for intrapartum GBS prophylaxis is not well characterized. The objective of this study was to describe trends in the use of vancomycin among women undergoing vaginal delivery with group B Streptococcus (GBS) colonization. Methods An administrative inpatient database that includes medications was analyzed to evaluate antibiotic use in women undergoing vaginal delivery hospitalizations complicated by GBS colonization from January 2006 to March 2015. Patients with other obstetric or infectious indications for antibiotics were excluded. Frequency of use of individual antibiotic agents was determined. The Cochran–Armitage test was used to assess temporal trends. An adjusted log-linear regression model accounting for demographic and hospital factors with vancomycin receipt as the outcome was performed with adjusted risk ratios (aRR) and 95% confidence intervals (CI) as the measure of effect. Hospital level variation in administration of vancomycin was also evaluated. Results 469,717 deliveries met inclusion criteria and were included in this analysis. Use of vancomycin increased from 0.8% of patients in 2006 to 3.8% of patients in the first quarter of 2015. Comparing 2015 to 2006 both the unadjusted (relative risk 4.89 95% CI 4.26–5.60) and adjusted (aRR 4.52 95% 3.94–5.19) models demonstrated significantly increased likelihood of vancomycin administration. In evaluating hospital level vancomycin use, variation was noted with 8.0% of centers administering vancomycin to ≥6.0% of patients. Conclusions Vancomycin is becoming increasingly commonly used for intrapartum GBS prophylaxis. Further research and quality improvements initiatives are indicated to optimize intrapartum GBS antibiotic prophylaxis.

Age-stratified analysis of serotype-specific baseline immunity against group B streptococcus

ABSTRACT Group B streptococcus (GBS) vaccines are currently under development. Data on the natural immunity in diverse age groups will aid establishing the GBS immunization policy. In this study, thirty serum samples were collected from three age groups (neonates/infants, pregnant women, and the elderly) between August 2016 and July 2017. Serotype-specific opsonophagocytic activity (OPA) was assessed using a GBS multiplex opsonophagocytic killing assay (MOPA) against serotypes Ia, III, and V. The mean OPA titers for serotype Ia of the three age groups were not significantly different (p = .156), but tended to be lower in neonates/infants (mean ± standard deviation, 137 ± 278). For serotype III and V, the mean OPA titer of neonates/infants (338 ± 623 and 161 ± 445, respectively) was significantly lower than that of pregnant women (1377 ± 1167 and 9414 ± 6394) and the elderly (1350 ± 1741 and 3669 ± 5597) (p = .002). In conclusion, the lower levels of OPA titers against all tested serotypes in neonates/infants, despite high maternal titers, indicates that intrapartum GBS vaccinations may be required for efficient placental transfer of serotype-specific GBS antibodies with high avidity.

Intrapartum PCR-assay for detection of Group B Streptococci (GBS).

ObjectiveWe have recently introduced intrapartum PCR-testing for group B streptococcus (GBS) in women in labor with prolonged rupture of membranes or preterm delivery to offer intrapartum antibiotic prophylaxis only for GBS positive women.The goal of the present study is to report our experience and results from the first half year of GBS testing.Study designThis is a retrospective study. Rectovaginal swabs from 321 women presenting in the labor ward with pre-labor rupture of membranes for >14 h/rupture of membranes during delivery for >14 h, or labor between gestational weeks 35 0/7 and 36 6/7 from February 7, 2017 to August 6, 2017, were tested.We performed a molecular GBS test (Xpert GBS®, Cepheid Ltd., Sunnyvale, USA).Data from patient files including mode of delivery, use of antibiotics, infection of mother and child are presented in more detail.Data on the PCR results from the first year of testing were also collected.ResultsIn the first half-year of testing a positive GBS test result was found in 58 (18.1%) and a negative test result in 263 women (81.9%). No invalid test result was achieved.The indication for performing PCR testing was PROM > 14 h or rupture of membranes during labor for >14 h in 266 women (82.9%) and labor in gestational weeks 35 0/7–36 6/7 in 44 women (13.7%). In the remaining 11 women, the PCR test was performed for other reasons.Of the 321 women tested 126 (39%) received antibiotics during labor.Ten women (3.4%) were treated after delivery on suspicion of infection. 25 newborns (7.8%) were treated with antibiotics. In 11 cases, the treatment was stopped after 2–4 days as there were no signs of infection.ConclusionsThe introduction of the intrapartum GBS test in selected groups of women who gave birth in our department has been well accepted by the women, the midwifes and doctors. The result of the test is available within two hours, and as we only offer intrapartum antibiotic prophylaxis to GBS-positive women, we have reduced the use of antibiotics to approximately 40% in the groups tested, without an increase of infection in mother or child.

Prevalence of group B streptococcus anogenital colonization and feasibility of an intrapartum screening and antibiotic prophylaxis protocol in Cameroon, Africa.

To evaluate group B streptococcus (GBS) colonization prevalence and feasibility of intrapartum GBS screening/antibiotic prophylaxis (IAP) in Cameroon, Africa. Prospective cohort in the Cameroon Baptist Convention Health Services network. Maternity providers collected anogenital swabs from consenting term women in labor for testing by a rapid GBS-polymerase chain reaction (PCR) system. Positive tests (GBS+) resulted in initiation of intravenous ampicillin until delivery. Primary outcomes were GBS prevalence and proportion of GBS+ women receiving ampicillin before delivery and more than 4hours before delivery. A total of 219 women were enrolled from January 10 to April 27, 2017. GBS prevalence was 12.3% (95% confidence interval [CI] 7.9-16.7) with GBS+ women more likely to reside in urban areas (19.6% vs 9.7%, P=0.004). Of 27 GBS+ women, 19 (70.4%) received ampicillin before delivery and 14 (51.9%) 4hours or longer before delivery. A median two doses of ampicillin (interquartile range [IQR] 1-5) were given and started at a median of 105minutes (IQR 90-155) after swab collection and 20minutes (IQR 10-45) after GBS result. Of the 8 women who did not receive ampicillin, 7 (87.5%) delivered before test results. A GBS IAP protocol is feasible in Cameroon and should be evaluated for widespread implementation in Cameroon and other low-income countries to decrease GBS-related morbidity.

Comparison of Three Nucleic Acid Amplification Tests and Culture for Detection of Group B Streptococcus from Enrichment Broth.

Colonization of the gastrointestinal and genitourinary tracts of pregnant women with group B Streptococcus (GBS) can result in vertical transmission to neonates during labor/delivery. GBS infections in neonates can cause severe complications, such as sepsis, meningitis, and pneumonia. Accurate detection is critical because administration of intrapartum antibiotics can significantly reduce transmission. We compared the clinical sensitivities of three nucleic acid amplification tests (NAATs), the Hologic Panther Fusion GBS, Luminex Aries GBS, and Cepheid Xpert GBS LB assays, to that of the standard of care culture method recommended for GBS screening using 500 vaginal-rectal swab specimens after 18 to 24 h of broth enrichment. We identified 108 positive specimens (21.6%) by culture, while at least 1 of the 3 NAATs was positive for GBS in 155 specimens (31.0%). All 108 specimens positive by culture were also detected by the Panther Fusion assay, while 107/108 (99.1%) were detected by the Cepheid Xpert and Luminex Aries assays. Of the 61 specimens positive by at least 1 NAAT but negative by culture, 24 (39.3%) were positive by all 3 NAATs, suggesting that they represent true positives (TPs). NAATs offer less hands-on time, greater throughput, faster time to result, and potentially greater sensitivity than culture methods, and they should be considered the new gold standard for intrapartum GBS screening.

Racial disparities in intrapartum group B Streptococcus colonization: a higher incidence of conversion in African American women.

To compare the incidence of group B Streptococcus (GBS) conversion from a negative antepartum to a positive intrapartum culture among women who self-identify as non-Hispanic black, Hispanic, or non-Hispanic white. This was a prospective cohort study of women with a negative rectovaginal GBS culture obtained within 35 days of enrollment. An intrapartum rectovaginal swab was collected and cultured for GBS. Data were compared with chi-square, Fisher's exact, or Wilcoxon rank-sum test. Modified Poisson regression was used. We enrolled 737 women; 75.4% were non-Hispanic white, 17.6% were non-Hispanic black, and 6.9% were Hispanic. Non-Hispanic black women were more likely to convert to GBS positive than non-Hispanic white women, 9.2% as compared to 5.3% (RR: 2.0; 95% CI: 1.02-3.8). The increased incidence of positive intrapartum GBS cultures among non-Hispanic black women suggests that non-Hispanic black race is a risk factor for GBS conversion in the late third trimester.

2282. Age-Stratified Analysis of Serotype-Specific Immunity Against Group B Streptococcus

BackgroundDevelopment of group B streptococcus (GBS) vaccine is currently underway. In order to establish the immunization policy for the future, it is necessary to understand the basal immune level of risk groups in each country.MethodsThirty serum samples were collected from each risk group (neonates/infants, pregnant women and the elderly) between August 2016 and July 2017 at Korea University Guro hospital. Serotype-specific opsonic index (OI) was assessed using GBS multiplex opsonophagocytic killing assay (MOPA) against serotype Ia, III and V, which are most prevalent worldwide.ResultsThe mean age of neonates/infants, pregnant women, and the elderly was 1.3 months (range, 1–3 months), 31.9 years (range, 23–41 years) and 68.8 years (range 65–76 years), respectively. Baseline OI of each risk group measured by MOPA was shown in Table 1. The mean OI of serotype Ia was not significantly different among three risk groups (P = 0.156), but relatively lower in the neonates/infants group (mean ± standard deviation, 137 ± 278). For serotype III, the mean OI of neonates/infants (338 ± 623) was significantly lower compared with those of pregnant women (1,377 ± 1167) and old adults (1,350 ± 1741)(P = 0.002); Overall 60% of neonates/infants showed OI below 100. As for the serotype V, OI was particularly lower in neonates/infants (161 ± 445) compared with the elderly (3,669 ± 5,597) and pregnant women (9,414 ± 6,394) with statistically significant differences between three risk groups (P < 0.001).ConclusionConsidering the relatively low OI of neonates/infants despite high maternal titer, intrapartum GBS vaccination might be required to ensure efficient placental transfer of serotype-specific GBS antibodies with high avidity.Table 1.Comparison of Baseline Opsonic Indexes Between Risk Groups: Mean Opsonic Indexes and 95% Confidence IntervalsSerotypesGroupsOpsonic Index (Mean)95% CI P-ValueIaNeonates/infants13733–2410.596Pregnant women28517–552The Elderly2313–459IIINeonates/infants338105–5700.002Pregnant women1377941–1813The elderly1350700 - 2000VNeonates/infants161-5–327<0.001Pregnant women94146825–12003The elderly36691579–5759Disclosures All authors: No reported disclosures.

Intrapartum group B Streptococcus screening in the labor ward by Xpert® GBS real-time PCR.

Group B Streptococcus (GBS) is the leading cause of neonatal infections in industrialized countries. Intrapartum antibiotic prophylaxis (IAP) given to colonized parturients is a key step for the prevention of neonatal early-onset infection. We compared the performances of Xpert® GBS polymerase chain reaction (PCR) (Cepheid, Sunnyvale, CA, USA) as a point-of-care system in labor wards to standard culture for intrapartum GBS detection. Pregnant women with a GBS-positive antenatal screening were prospectively included. A vaginal double swab was collected at the time of delivery for point-of-care Xpert® GBS PCR and GBS culture. A total of 565 pregnant women were included. Valid Xpert® GBS results were obtained for 488 (86.4%) women on the first attempt. Repeat testing improved the PCR success to 516 (91.3%) women. Among the 305 women positive for GBS by culture at delivery, only 238 (78.0%) were positive by Xpert® GBS PCR, cycle thresholds being correlated to culture quantification. Among 260 women negative for GBS culture, 56 (21.5%) were positive by Xpert® GBS PCR, including 50 where IAP was initiated before vaginal sampling. Overall, among the 565 women with GBS antenatal positive culture, only 335 (59.3%) were still positive at delivery whatever the technique used, resulting in unnecessary IAP for 40% of them. This large cohort study comparing intrapartum to antepartum GBS detection provides evidence that (i) Xpert® GBS PCR might be a valuable solution for intrapartum GBS detection compared to culture-based strategies and (ii) laboratory training of non-specialized staff is mandatory to reach the performances required for point-of-care tests.

Test de dépistage rapide intra partum du portage vaginal de streptocoque du groupe B (SGB) pour le repérage des nouveau-nés à risque d’infection néonatale précoce à SGB. Étude observationnelle analytique dans une maternité de type III

Group B streptococcus (GBS) is the most common infectious agent responsible for early-onset bacterial sepsis (EOS) in term newborns. French prevention of perinatal GBS disease guidelines recommend screening for maternal vaginal GBS colonization at the 9th month of pregnancy, and use of intrapartum antibiotic prophylaxis (IAP) in case of detected GBS vaginal colonization. Peripheral bacterial sampling (gastric aspiration, ear, or meconium) and measurement of C-reactive protein (CRP) are performed in asymptomatic newborns in case of infectious risk factors and/or incomplete IAP. The aim of this study was to investigate the relation between a rapid intrapartum screening test for GBS during labor in term parturients and infants developing GBS EOS and in comparison to current recommendations. We conducted an observational analytic single-center study, with use of a rapid intrapartum GBS screening test, at Toulouse University Hospital. A total of 1416mother-newborn dyads were prospectively included between 31/01/2012and 17/08/2012. Vaginal GBS colonization was found at the 9th month of pregnancy in 148mothers (10.6%), and 176mothers (12.5%) were screened positively at delivery using intrapartum GBS rapid polymerase chain reaction assay (GBS PCR) (P=0.025). No confirmed neonatal GBS EOS was found. Nine infants had suspected GBS EOS because of a positive peripheral bacterial finding and elevated CRP. In these infants, seven pregnant mothers were GBS-positive with GBS PCR assay during labor, and four women were positive on prenatal culture at the 9th month of pregnancy. The diagnostic values of the two tests highlighted a nonsignificant superiority of intrapartum GBS PCR assay (AUC=0.83 [0.68-0.97] vs. 0.67 [0.50-0.84]), (P=0.057). The negative predictive value was improved with intrapartum PCR assay (negative likelihood ratio [LR]: 0.3 [0.1-0.9] vs. 0.6 [0.4-1.1]). Intrapartum GBS PCR assay provided its best positive predictive value in the absence of complete AIP and without other infectious factors (positive LR: 21.3 [15.4-29.5]). These results suggest that the intrapartum GBS PCR assay offers a better predictive value of GBS EOS than the usual vaginal culture swab at the 9th month but requires confirmation by large studies.

Rapid Group B streptococcus screening methods in late pregnancy and the maternal-neonatal outcomes

To study the sensitivity of the quantitative fluorescence polymerase chain reaction (QF-PCR) in detecting group B streptococcus (GBS) in late pregnant women and the influence of vaginal/rectal GBS colonization on the maternal-neonatal outcomes. A total of 2020 swabs were taken from 505 women who received routine culture and QF-PCR screening at 35 and 37 weeks of gestation from September, 2013 to April, 2014 at Peking Union Medical College Hospital.For each subject, two vaginal and two rectal swabs were collected.Samples with discordant results from these two methods were further analyzed by gene sequence determination.GBS isolates were subjected to antimicrobial susceptibility testing using the Kirby-Bauer method.The laboratory results were collected and the pregnant outcomes were followed. Of the 38 GBS positive cases , GBS could be detected for 13 by both culture and QF-PCR methods, for 24 only by QF-PCR, for 1 exclusively by culture.GBS colonization rate, sensitivity and negative predictive value (NPV) for culture were 2.8%, 36.8%, and 95.1%, respectively.GBS colonization rate, sensitivity and negative predictive value (NPV) for QF-PCR were 7.3%, 97.4%, and 99.8%, respectively.There was significant difference between the two methods (P<0.001). A higher proportion of GBS were isolated from the rectum (6.7%) as compared to the vagina (2.8%) (P<0.01). GBS isolates were all (100%) sensitive to penicillins, cephalosporins, vancomycin and linezolid.Erythromycinresistance was present in 47.4% of the GBS isolates, while clindamycin resistance was present in 36.8%.Compared with the GBS negative group, the GBS positive group had higher incidence of gestational hypertension and colpitis mycotica (all P<0.05), but had similar incidence of maternal and neonatal outcomes, like neonatal infection, septicemia, puerperal disease. QF-PCR assay provides an accurate and rapid method for detecting GBS in late pregnancy.Rectum is also an important site for detection of GBS.Penicillin therapy remains an appropriate first-line antibiotic choice for intrapartum GBS chemoprophylaxis, with erythromycin and clindamycin resistance rate being high.The relationship between maternal GBS colonization and the pregnancy outcome needs to be further studied.

Do we need a different approach to GBS screening?

Group B Streptococcus (GBS) infections remain an important cause of perinatal complications, despite advanced preventive measures. The most common clinical symptoms of early-onset disease, diagnosed in neonates up to 7 days of life, are sepsis and pneumonia. Late-onset disease is diagnosed in children between 7 and 89 days of life and presents also in forms of other infections. As a result of collaborative efforts of clinicians, researchers and many organizations, various recommendations for intrapartum prevention of perinatal GBS disease have been issued so far. Revised 2002 CDC guidelines for the prevention of early-onset GBS disease recommended universal culture-based screening of all pregnant women at 35-37 weeks of gestation to optimize the identification of those who should receive intrapartum antibiotic prophylaxis (IAP). They were customized by the Polish Gynecological Society and applied in Poland as well. As a result of preventive efforts worldwide, global incidence of GBS infections has declined dramatically over the past 15 years. About 10-30% of pregnant women are colonized with Group B Streptococcus. According to the literature, GBS culture at 35 to 37 weeks of gestation has about 95% negative predictive value for the absence of colonization at the time of labor. However, studies reporting early-onset GBS disease in newborns found that about 60 to 80% of all cases occurred in neonates with negative maternal screening during pregnancy. If the only available screening test is vagino-rectal swab during pregnancy about 7.5% of women with GBS colonization during labor are not administered IAP. It seems optimal to perform routine screening not during pregnancy but directly before the delivery--preferably at the time of regular uterine contractions or the rupture of membranes. As the screening test should be widely accessible and rapid, the usual microbiological culture is not a suitable option. Recently new biochemical and genetic methods have become available. Polymerase chain reaction (PCR) and optical immunoassay are candidates for rapid patient intrapartum GBS testing to determine whether women in labor are colonized with GBS. PCR tests have the sensitivity of over 90% with the specificity of 99%, which is about 13% higher than microbiological culture. According to the literature, IAP does not reduce the overall neonatal mortality mortality due to GBS infection, or due to other bacterial infections. The incidence of early-onset GBS infection was reduced with IAP in comparison to no intrapartum prophylaxis, but there was no difference in late-onset GBS disease occurrence. Besides GBS, IAP may influence maternal and neonatal infections caused by other pathogens. Moreover, it can also induce GBS and no-GBS pathogen resistance to antibiotics. It therefore seems necessary to replace the current type of GBS screening with GBS DNA PCR intrapartal test--a rapid, highly sensitive and specific method of carrier identification--in order to optimize IAP and, eventually to decrease the rate of early onset GBS disease in neonates.

Intrapartum polymerase chain reaction for detection of group B streptococcus colonisation

Lower vaginal swabs were collected to compare the intrapartum polymerase chain reaction (PCR) test to the standard antepartum culture for detection of group B streptococcus (GBS) colonisation. Four hundred and forty-five pregnant women with documented antepartum GBS cultures, who did not receive either antepartum or intrapartum antibiotics, were included in this prospective study. At the time of delivery and before the intrapartum antibiotic prophylaxis (IAP), double swabs were collected, one of the swab was used in the GBS molecular-based (PCR) test and the other was processed for GBS culture in Ahmadi Hospital Clinical Laboratory. Neonates were examined after delivery to diagnose GBS sepsis, and using intrapartum GBS culture as gold standard test; the intrapartum PCR test was compared to the antepartum culture. The sensitivity and specificity of antepartum culture to diagnose GBS colonisation were 73 & 95.5%, respectively, compared with 98.3% sensitivity & 99% specificity for intrapartum PCR test (P>0.05). Although the intrapartum PCR test was more accurate (98.8%) for detection of GBS colonisation than antepartum culture (90%), its accuracy was significantly different. The neonatal GBS sepsis was significantly related to positive intrapartum cultures, and intrapartum PCR tests, but was not related to positive antepartum cultures (the IAP to the antepartum GBS-positive mothers reduces GBS sepsis of their neonates). The intrapartum PCR test is an accurate bedside test and it has the potential to be used as intrapartum screening for GBS colonisation allowing appropriate management of mothers and neonates.

Intrapartum Group B streptococcus detection by rapid polymerase chain reaction assay for the prevention of neonatal sepsis

Group B streptococcus (GBS) is a leading cause of infectious neonatal morbidity and mortality. Timely and accurate identification of colonized mothers is imperative so that antibioprophylaxis can be implemented during labour to reduce the risk of neonatal sepsis. We planned our study to analyse the diagnostic accuracy of an intrapartum PCR assay to identify GBS-colonized women and to allow the implementation of correct (i.e. at least 4 h) intrapartum antibiotic prophylaxis based on the PCR results. We included 695 women in labour who were tested for rectovaginal GBS carriage by culture and PCR. Women were also screened at 35–37 weeks of gestation. Intrapartum GBS colonization was 19.3%. Assay sensitivity was 81.0% for antenatal culture and 85.0% for intrapartum PCR; p 0.72. GBS colonization (n = 107) was known at least 4 h before delivery in 68 (64%) and 73 (68%) women based on antenatal culture and intrapartum PCR, respectively. Among 43 women delivering preterm, correct status was known at least 4 h before delivery in 10 (23%) and 32 (74%) women according to antenatal culture and intrapartum PCR, respectively. These results support the concept that GBS screening can be performed routinely during labour in a clinical setting. The intrapartum approach is at least as accurate as the antenatal screening, with the additional advantage of identifying women delivering preterm or not followed during pregnancy.

Evaluation of a rapid, real-time intrapartum group B streptococcus assay

We sought to evaluate an intrapartum nucleic acid amplification test (NAAT) for group B streptococcus (GBS). This was a prospective cohort study of 559 women comparing intrapartum GBS culture with antepartum culture and intrapartum NAAT. GBS prevalence was 19.5% by antepartum culture and 23.8% by intrapartum culture. Compared with intrapartum culture, antepartum culture had 69.2% sensitivity (60.6-76.9%) and 96.0% specificity (93.7-97.7%). The NAAT demonstrated sensitivity of 90.8% (84.6-95.2%), specificity of 97.6% (95.6-98.8%), and predictive values >92%. The incidence of discordant cultures was 10.4%. Of the women with negative antepartum and positive intrapartum cultures, only 1 (2.4%) received intrapartum antibiotics. Compared with white women, black (P = .02) and Hispanic (P = .02) women were more likely to have discordant cultures. This intrapartum NAAT has excellent characteristics. It may be superior to antepartum culture for detecting intrapartum GBS-allowing more accurate management of laboring mothers and reducing neonatal GBS sepsis.

Variation in erythromycin and clindamycin resistance patterns between New Zealand and Australian group B streptococcus isolates

Intrapartum chemoprophylaxis for group B streptococcus (GBS) carriers reduces the risk of early-onset neonatal GBS infection. For women with β-lactam allergy, either erythromycin or clindamycin are administered. Recent reports worldwide suggest that GBS resistance to these antibiotics is increasing. To compare erythromycin and clindamycin resistance phenotypes in invasive neonatal GBS isolates across New Zealand and Australia over the past two decades and to determine whether regional variation in resistance patterns exist. Invasive neonatal GBS isolates were collected from laboratories across New Zealand (n=107) and Australia (n=74) over two time periods (1992-1994 and 2002-2004 in New Zealand; 1982-2001 and 2002-2006 in Australia) and subjected to standard antibiotic susceptibility testing. A nested sub-study in New Zealand examined antibiotic susceptibilities of 112 maternal colonising GBS isolates during 2003-2004. Erythromycin resistance among invasive neonatal GBS isolates increased across both countries over the past decade, with similar rates of resistance in New Zealand (9%) and Australia (6%) in recent years. New Zealand erythromycin-resistant GBS isolates commonly displayed cross-resistance to clindamycin. Also, there were significantly higher rates of isolated clindamycin resistance in GBS isolates from New Zealand than Australia (P=0.034). Maternal GBS isolates from New Zealand showed similar resistance patterns to neonatal isolates. Erythromycin and clindamycin resistance among invasive neonatal GBS isolates has emerged in both New Zealand and Australia over the past decade and is consistent with global trends in GBS resistance patterns. Although regional variations exist, these findings should be considered when implementing intrapartum GBS prevention strategies.

Evaluation of the Xpert® group B streptococcus real-time polymerase chain reaction assay compared to StrepB Carrot Broth™ for the rapid intrapartum detection of group B streptococcus colonization

Xpert group B streptococcus (GBS) was compared to StrepB Carrot Broth™ (SCB) for the detection of intrapartum GBS colonization by dually collecting vaginal/rectal swabs from 231 women. Xpert GBS detected all of the cases (45, 19.5%), but 4 were missed by SCB. A rapid Xpert GBS service for women in labor would increase costs by ∼$55 000 per annum in our region.

40: Utility of an intrapartum rapid group B streptococcus test

Group B streptococcus (GBS) early-onset sepsis is a leading cause of neonatal morbidity and mortality. Two-thirds of infants with GBS sepsis are born to mothers with a negative third-trimester GBS culture—the current screening test. Given the transient nature of GBS colonization we evaluated the test characteristics of a rapid intrapartum GBS test and the current screening test along with the incidence of GBS conversion from the third trimester to intrapartum.