Factors associated with choice of approach for Group B streptococcus screening

Group B Streptococcus real-time PCR may potentially reduce intrapartum maternal antibiotic treatment

BACKGROUND

Protocols for preventing early-onset group B streptococcal (GBS) neonatal infection may result in unnecessary antibiotics administration. Real-time polymerase chain reaction (PCR) can provide a result within 30-60 min and has been found to be specific and sensitive for defining intrapartum GBS status.

OBJECTIVE

To evaluate whether implementation of GBS fast real-time PCR to all women who require GBS prophylaxis may reduce the use of maternal prophylactic antibiotics.

METHODS

This prospective cohort study included women admitted to a single delivery ward who required prophylactic antibiotics either due to a positive antepartum GBS culture screening performed at 35-37 weeks or due to an unknown GBS status with an intrapartum risk factor. All the women were tested by a double vaginal swab (real-time PCR and culture) as soon as it became apparent, they required antibiotic prophylaxis and prior to its administration.

RESULTS

Between May 2019 and August 2020, 303 women met eligibility criteria and were enrolled, but four were excluded from the analysis due to failed culture or PCR tests. Of 299 women included in the study, 208 (69.5%) and 180 (60.2%) women, showed no evidence of GBS on intrapartum culture or PCR, respectively. Of 89 GBS antepartum carriers, 43 (48.3%) and 32 (35.9%) had negative intrapartum culture and PCR results, respectively. Of the 210 women with risk factors, 165 (78.5%) were culture negative and 148 (70.4%) had a negative PCR. Using intrapartum culture as the gold standard, intrapartum GBS real-time PCR was found to have a sensitivity of 97.8% (95% confidence interval [CI] 92.3, 99.7) and a specificity of 85.6% (95% CI 80.1, 90.1).

CONCLUSIONS

Compared with antepartum universal culture screening or intrapartum risk-factor assessment, the need for maternal antibiotic treatment may be substantially reduced by implementation of intrapartum GBS real-time PCR, without compromising the sensitivity of GBS detection.

Re-evaluating Perinatal Group B Streptococcal screening in Israel - Is it time for a change in policy?

Group B streptococcal early-onset disease (EOGBSD) is a significant cause of morbidity and fatality in newborns. Current policy in Israel is risk-based management. Our aim was to re-evaluate the current screening policy for Group B Streptococcus (GBS), considering colonization and prevalence rates and costs estimates. This was a retrospective cohort study including term pregnancies between 2015 and 2016 insured by Maccabi Healthcare Services (MHS). A costs estimation model was performed comparing three approaches: universal culture-based screening, current policy in Israel and the current clinical scenario. Out of 54,759 pregnancies, 46.3% women undergo GBS culture-based screening. Overall GBS colonization rates in screened women were 21%. Six EOGBSD cases were identified, all offspring of mothers who were not screened. EOGBSD prevalence rate was 11 per 100,000. Universal culture-based screening was found to be 50% less costly than the current risk-based policy, and would have prevented 20.29 per 100,000 cases. Universal GBS culture-based screening was found to be more cost-effective, compared to the current policy and screening behaviors. Due to the clinical and economic benefits, we recommend that a change in policy should be considered.

Group B Streptococcus serotypes associated with different clinical syndromes: Asymptomatic carriage in pregnant women, intrauterine fetal death, and early onset disease in the newborn

Objectives

To study Group B Streptococcus (GBS) isolates associated with different clinical syndromes: asymptomatic carriage in pregnant women, intrauterine fetal death (IUFD), and early onset disease (EOD) in the newborn.

Methods

GBS isolates were collected from asymptomatic pregnant women admitted for labor, IUFD cases, and neonates with EOD. Serotypes and antibiotic susceptibilities were determined. Multilocus sequence typing (MLST) was performed to assess genetic epidemiology.

Results

GBS carriage rate was 26.1% (280/1074). The dominant serotype among asymptomatic pregnant women was VI [98/240 women (40.8%)], followed by serotypes III, V and IV in 42/240 (17.5%), 30/240 (12.5%) and 28/240 (11.7%) women, respectively. The dominant serotype in IUFD cases was serotype VI [10/13 (76.9%)]. In contrast the prevalent serotype among EOD cases was III [16/19 (84.2%)]. ST-1 was associated with IUFD [7/13 (53.8%)], ST-17 was associated with serotype III and EOD in the newborn 14/19 (73.7%)]. Erythromycin and clindamycin resistance reached 36.8%, 7.7% and 20.0%among EOD, vaginal carriage and IUFD, respectively.

Conclusions

Serotypes VI and ST-1 were dominant among asymptomatic pregnant women and in IUFD cases while EOD was associated with serotype III and ST-17. Invasive mechanisms thus may differ between IUFD and EOD in the newborn and virulence may be related to capsule serotype. Resistance rates to erythromycin and clindamycin were high in EOD cases.

Assessment of maternal GBS colonization and early-onset neonatal disease rate for term deliveries: a decade perspective

Objective To assess the maternal group B streptococcal (GBS) colonization rate and neonatal early-onset GBS (EOGBS) disease in term deliveries, a decade apart. Methods This was a retrospective computerized study between 2005 and 2016. A universal GBS culture-based approach gradually replaced the GBS risk-oriented screening. A vaginal-rectal culture taken at 35-37 weeks was recorded at admission for delivery. Results We identified 149,910 term deliveries during the study period. GBS status was recorded in 53,879 (35.9%) cases. The GBS screening rate constantly increased from 20% in 2005 to 47.5% in 2016. GBS colonization rates significantly decreased, from 50.3% in 2005 to 31.7% in 2016, P<0.001. Overall, EOGBS disease was diagnosed in 37 term neonates (0.25 per 1000 live births.). The rate of EOGBS in neonates decreased dramatically from 0.361 per 1000 deliveries between 2005 and 2009 to 0.19 per 1000 deliveries between 2010 and 2016 (P<0.05). During the latter period, over 35% of the deliveries were screened for GBS. Remarkably, 64.9% of the EOGBS originated in the non-screened population. Conclusion The universal screening policy was associated with a significant decrease in neonatal EOGBS and therefore should be adopted. Further national surveillance studies should be performed in order to validate this approach.

High prevalence of Group B Streptococcus colonization among pregnant women in Amman, Jordan

Background

Little is known of the burden of Group B Streptococcus (GBS) colonization among pregnant women in Jordan. We conducted a pilot study to determine the prevalence of GBS among pregnant women in Amman, Jordan, where GBS testing is not routine. We also explored GBS serotypes and the performance of a rapid GBS antigen diagnostic test.

Methods

We collected vaginal-rectal swabs from women who presented for labor and delivery at Al-Bashir Hospital. Three methods were used to identify GBS: Strep B Rapid Test (Creative Diagnostics), blood agar media (Remel) with confirmed with BBL Streptocard acid latex test (Becton Dickinson), and CHROMagar StrepB (Remel). Results were read by a senior microbiologist. We defined our gold standard for GBS-positive as a positive blood agar culture confirmed by latex agglutination and positive CHROMagar. PCR testing determined serotype information. Demographic and clinical data were also collected.

Results

In April and May 2015, 200 women were enrolled with a median age of 27 years (IQR: 23–32); 89.0% were Jordanian nationals and 71.9% completed secondary school. Median gestational age was 38 weeks (IQR: 37–40); most women reported prenatal care (median 9 visits; IQR: 8–12). Median parity was 2 births (IQR: 1–3). Pre-pregnancy median BMI was 24.1 (IQR: 21.5–28.0) and 14.5% reported an underlying medical condition. Obstetric complications included gestational hypertension (9.5%), gestational diabetes (6.0%), and UTI (53.5%), of which 84.5% reported treatment. Overall, 39 (19.5%) of women were GBS-positive on blood agar media and CHROMagar, while 67 (33.5%) were positive by rapid test (36% sensitivity, 67% specificity). Serotype information was available for 25 (64%) isolates: III (48%), Ia (24%), II (20%), and V (8%). No demographic or clinical differences were noted between GBS+ and GBS-negative women.

Conclusions

Nearly one in five women presenting for labor in Jordan was colonized with GBS, with serotype group III as the most common. The rapid GBS antigen diagnostic had low sensitivity and specificity. These results support expanded research in the region, including defining GBS resistance patterns, serotyping information, and risk factors. It also emphasizes the need for routine GBS testing and improved rapid GBS diagnostics for developing world settings.

Outcome of a screening program for the prevention of neonatal early-onset group B Streptococcus infection: a population-based cohort study in Inner Mongolia, China

PURPOSE

Invasive early-onset group B Streptococcus infection (EOGBS) is an important cause of severe neonatal complications but study on comprehensive GBS screening is lacking in China. This study aims to investigate the outcome of a regional anterpartum screening program for EOGBS prevention and to estimate the pros and cons of a new GBS screening strategy employed.

METHODS

We performed an optimized hospital strategy for GBS screening, which targeted expectant mothers (including those with preterm births) from January 2016 to December 2016 in a population-based cohort. Three common screening strategies were simulated to estimate the availability of the hospital strategy used in this study.

RESULTS

Altogether, 9770 eligible women were tested and the rate of GBS carriage was 2.7  % (266/9770). In total, 198 of the 266 maternal GBS carriers accepted intrapartum antibiotic prophylaxis (IAP) treatment. Among the 9860 neonates of 9770 mothers, four cases of EOGBS infection were identified and one case was missed (EOGBS incidence with screening and IAP: 0.5/1000). Risk factors for maternal GBS colonization included preterm birth (between 35 and 37 weeks) [odds ratio (OR)=1.7 (95  % confidence interval: 1.22-2.33)], region of origin, resident areas, maternal age (older than 34 years) [OR=1.5 (1.06-2.09)], prelabour rupture of membranes [OR=1.8 (1.34-2.35)], gestational diabetes mellitus [OR=1.6 (1.14-2.28)] and maternal mild anemia (Hb: 90-110 g dl^-1) [OR=1.5 (1.16-2.06)]. This new screening strategy resulted in less antibiotic exposure and least number of cases missed.

CONCLUSIONS

Our findings illustrate that this perinatal screening (including preterm births) for prevention of EOGBS infection can be implemented in the Inner Mongolian area.

The recurrence risk of group B Streptococcus in consecutive deliveries

Background: Group B streptococcus (GBS) is a significant cause of neonatal morbidity and mortality. GBS maternal colonization status was found to be transient, intermittent, or chronic and screening during each subsequent pregnancy was advised. Recent studies showed that GBS colonization rate was higher among women with history of GBS positive in prior pregnancy.Objective: To establish the cumulative risk of group B streptococcus (GBS) colonization in consecutive subsequent term deliveries as referred to the first delivery GBS colonization status.Study design: A retrospective cohort study, based on a validated computerized database at a tertiary single center between the years 2005-2016. Pregnant women preform vaginal-rectal culture at 35-37 weeks of gestation. We analyzed records of term primiparas women that had records of up to three additional term consecutive deliveries and GBS colonization status.Results: 8641 primiparas met inclusion criteria; 3972 (46.0%), 993 (11.5%), and 243 (2.8%) had second, third, and fourth consecutive deliveries with recorded GBS status respectively. The overall colonization rate for primiparas was 28.4%. The cumulative rates and cumulative risks of repeated GBS positive colonization at the second, third and fourth term consecutive deliveries were 62.0%, 6.93 (95% CI 5.96-8.06), 68.0%, 5.05 (95% CI, 3.67-6.93), and 66.1%, 2.96 (95% CI, 1.54-5.68), respectively. Notably, after a negative GBS colonization in the first, second, and third repeated deliveries, the rate and cumulative risk of GBS positive in each consecutive delivery was significantly lower: 18.2%, 0.14, (95% CI 0.12-0.17), 19.4%, 0.21 (95% CI 0.15-0.28), and 21%, 0.26 (95% CI 0.13-0.51) for the second, third, and fourth consecutive deliveries, respectively.Conclusion: GBS colonization status at the time of first pregnancy is a milestone for the colonization risk in subsequent term deliveries. This risk evaluation may influence the decision-making process for future screening and intrapartum antibiotic prophylaxis for term consecutive deliveries.