Intrapartum antibiotic prophylaxis for Group B Streptococcus: has the time come to wait more than 4 hours?

Is Group B Streptococcus Colonization Associated with Maternal Peripartum Infection in an Era of Routine Prophylaxis?

OBJECTIVE

This study aimed to assess whether colonization with group B streptococcus (GBS) is associated with maternal peripartum infection in an era of routine prophylaxis.

STUDY DESIGN

This study presented a secondary analysis of women delivering ≥37 weeks who underwent a trial of labor from the U.S. Consortium on Safe Labor (CSL) study. The exposure was maternal GBS colonization and the outcome was a diagnosis of chorioamnionitis, and secondarily, analyses were restricted to deliveries not admitted in labor and measures of postpartum infection (postpartum fever, endometritis, and surgical site infection). Logistic regression with generalized estimating equations was used accounting for within-woman correlations. Models adjusted for maternal age, parity, race, prepregnancy body mass index, pregestational diabetes, insurance status, study site/region, year of delivery, number of vaginal exams from admission to delivery, and time (in hours) from admission to delivery.

RESULTS

Among 170,804 assessed women, 33,877 (19.8%) were colonized with GBS and 5,172 (3.0%) were diagnosed with chorioamnionitis. While the frequency of GBS colonization did not vary by chorioamnionitis status (3.0% in both groups), in multivariable analyses, GBS colonization was associated with slightly lower odds of chorioamnionitis (adjusted odds ratio [AOR]: 0.89; 95% confidence interval [CI]: 0.83-0.96). In secondary analyses, this association held regardless of spontaneous labor on admission; and the odds of postpartum infectious outcomes were not higher with GBS colonization.

CONCLUSION

In contrast to historical data, GBS colonization was associated with lower odds of chorioamnionitis in an era of routine GBS screening and prophylaxis.

KEY POINTS

· Data in an era prior to routine group B streptococcus (GBS) screening and prophylaxis showed that maternal GBS colonization was associated with a higher frequency of maternal peripartum infection.. · In the current study, GBS colonization was associated with lower odds of chorioamnionitis in an era of routine GBS screening and prophylaxis.. · The results highlight potential benefits of GBS screening and intrapartum antibiotic prophylaxis beyond neonatal disease prevention, including mitigating the risk of maternal infectious morbidity..

Preventing Early-Onset Group B Streptococcus neonatal infection and reducing antibiotic exposure using a rapid PCR test in term prelabour rupture of membranes

BACKGROUND

How best to target intrapartum antibiotic prophylaxis (IAP) to minimise both Early-Onset Group B Streptococcus (EOGBS) neonatal infection and maternal/fetal antibiotic exposure is uncertain, with both routine-screening and risk-factor approaches available.

AIMS

This retrospective cohort study was undertaken to examine the outcomes of a hybrid risk-and-screen approach to EOGBS prevention using GBS polymerase chain reaction (PCR). The target population was women with term prelabour rupture of membranes (TermPROM) having the risk factor of prolonged rupture of membranes (ROM) ≥18 h.

MATERIALS AND METHODS

Non-labouring TermPROM women had rapid GBS PCR testing at presentation. GBS screen-positive women proceeded to induction of labour and received IAP. GBS screen-negative women were allowed home to await spontaneous labour and not given IAP regardless of duration of ROM, unless other risk factors developed. For all other women, the risk-factor approach was followed.

RESULTS

From 2009 to 2018, there were 20 cases of culture-positive EOGBS, a rate of 0.36/1000 live births (95% CI 0.22-0.56/1000), comparable to other recent reports. Over 2010-2018 when laboratory data were available, 1120 TermPROM women with ROM ≥18 h avoided antibiotics because they were GBS PCR-negative (2.3% of all births, 3.6% of vaginal births) while 338 TermPROM women with ROM <18 h received targeted antibiotics for being GBS-positive. No cases of EOGBS occurred in TermPROM women, those with ROM ≥18 h, or due to protocol-compliance failure.

CONCLUSIONS

A hybrid approach involving risk-factor-based IAP and intrapartum GBS PCR screening of non-labouring TermPROM women delivers acceptably low rates of EOGBS while minimising and better targeting antibiotic exposure.

Healthcare-associated infections including neonatal bloodstream infections in a leading tertiary hospital in Botswana

Background: Healthcare-associated infections (HAIs) increase morbidity, mortality, length of hospital stay and costs, and should be prevented where possible. In addition, up to 71% of neonates are prone to bloodstream infections (BSI) during intensive care due to a variety of factors. Consequently, the objectives of this study were to estimate the burden of HAIs and possible risk factors in a tertiary hospital in Botswana as well as describe current trends in bacterial isolates from neonatal blood specimen and their antibiotic resistance patterns.Methods: Point Prevalence Survey (PPS) in all hospital wards and a retrospective cross-sectional review of neonatal blood culture and sensitivity test results, with data abstracted from the hospital laboratory database.Results: 13.54% (n = 47) of patients had HAIs, with 48.9% (n = 23) of them lab-confirmed. The highest prevalence of HAIs was in the adult intensive care unit (100% - n = 5), the nephrology unit (50% - n = 4), and the neonatal intensive care unit (41.9% - n = 13). One-fourth of HAIs were site unspecific, 19.1% (n = 9) had surgical site infections (SSIs), 17% (n = 8) ventilator-associated pneumonia/complications, and 10.6% (n = 5) were decubitus ulcer infections. There were concerns with overcrowding in some wards and the lack of aseptic practices and hygiene. These issues are now being addressed through a number of initiatives. Coagulase Negative Staphylococci (CoNS) was the commonest organism (31.97%) isolated followed by Enterococci spp. (18.03%) among neonates. Prescribing of third-generation cephalosporins is being monitored to reduce Enterococci, Pseudomonas and Acinetobacter spp. infections.Conclusions: There were concerns with the rate of HAIs and BSIs. A number of initiatives are now in place in the hospital to reduce these including promoting improved infection prevention and control (IPC) practices and use of antibiotics via focal persons of the multidisciplinary IPC committee. These will be followed up and reported on.

Risk factors for neonatal early-onset group B streptococcus-related diseases after the implementation of a universal screening program in Taiwan

Background

We examined the risk for Group B streptococcus (GBS)-related diseases in newborns born to mothers who participated in a universal GBS screening program and to determine whether differences are observed in factors affecting the morbidity for neonatal early-onset GBS-related diseases.

Methods

This is a retrospective study and the study subjects were women who had undergone GBS screening and who gave birth naturally and their newborns between April 15, 2012 and December 31, 2013. Data from the GBS screening system database and the National Health Insurance database were collected to calculate the GBS prevalence in pregnant women and morbidity of newborns with early-onset GBS-related diseases.

Results

The GBS prevalence in pregnant women who gave birth naturally was 19.58%. The rate of early-onset infection caused by GBS in newborns decreased from the original 0.1% to 0.02%, a decrease of as high as 80%. After the implementation of the universal GBS screening program, only three factors, including positive GBS screening result (OR = 2.84), CCI (OR = 2.45), and preterm birth (OR = 4.81) affected the morbidity for neonatal early-onset GBS-related diseases, whereas other factors had no significant impact.

Conclusion

The implementation of the universal GBS screening program decreased the infection rate of neonatal early-onset GBS diseases. The effects of socioeconomic factors and high-risk pregnancy on early-onset GBS infections were weakened.

Vertical transmission of group B Streptococcus and associated factors among pregnant women: a cross-sectional study, Eastern Ethiopia

Background

Vertically transmitted group B Streptococcus (GBS) causes fetal and neonatal infections. However, there is limited information on the vertical transmission of GBS in low-income countries. This study, therefore, aimed to determine the rate of vertical transmission of GBS and associated factors among pregnant women in Eastern Ethiopia.

Subjects and methods

A cross-sectional, facility-based study was conducted among pregnant women in Harar town, Eastern Ethiopia, from June to October, 2016. GBS positivity of pregnant women was confirmed by culture of rectovaginal swab. Vertical transmission at birth was confirmed by culture on swabs taken from the ear canal, umbilicus, axilla, groin, and nose within 6 hours after birth. Prevalence ratio (PR) along with 95% CI was estimated to examine factors associated with vertical transmission using log binomial regression analysis.

Results

Out of 231 GBS-colonized pregnant women at delivery, 104 births were identified as GBS colonized with a vertical transmission rate of 45.02% and 95% CI: 38.49, 51.68. Of 104 vertical transmission cases, 65 (62.50%) received no intrapartum antibiotic prophylaxis (IAP), 28 (26.92%) received it <4 hours before delivery, and 11 (10.58%) received it ≥4 hours before delivery. Pre-labor rupture of membranes at term (PR: 1.93; 95% CI: 1.04, 3.57), prolonged rupture of the membrane ≥18 hours (PR: 1.76; 95% CI: 1.13, 2.74), intrapartum maternal fever (PR: 1.40; 95% CI: 1.13, 1.75), and IAP received ≥4 hours (PR: 0.17; 95% CI: 0.09, 0.30) were significantly associated with vertical transmission of GBS.

Conclusion

The magnitude of vertical transmission of GBS was very high. However, the rate of adequate IAP received by mothers was very low. Efforts need to be strengthened to screen pregnant women during antenatal care and IAP should be used as necessary. Furthermore, maternal vaccination may provide a feasible strategy to reduce the vertical transmission.

Are postnatal ampicillin levels actually related to the duration of intrapartum antibiotic prophylaxis prior to delivery? A pharmacokinetic study in 120 neonates

OBJECTIVE

To assess ampicillin levels according to the duration of intrapartum antibiotic prophylaxis (IAP).

DESIGN

Prospective cohort single-centre study.

SETTING

Tertiary care centre (Modena, Italy).

PATIENTS

120 neonates≥35 weeks' gestation exposed to IAP.

INTERVENTIONS

Neonates were divided into four groups, according to the duration of IAP prior to delivery: group 1 (n=30; <1 hour), group 2 (n=30; ≥1 and <2 hours), group 3 (n=30; ≥2 and <4 hours) and group 4 (n=30; ≥2 doses, ≥4 hours).

MAIN OUTCOME MEASURES

Blood samples were collected at delivery (from the umbilical cord) and at age 4 hours (from a peripheral vessel).

RESULTS

Median duration of IAP was 121 min (range 7-2045 min). Median ampicillin levels in umbilical cord blood were 10.4 µg/mL (IQR 6.4-14.9) and in peripheral blood were 4.7 µg/mL (IQR 2.8-6.4µg/mL). Umbilical cord blood levels reached a peak approximately 30 min after IAP and then declined significantly (p<0.001). Peripheral blood levels did not differ among study groups. Neonates exposed to a full loading dose (n=115) had peripheral blood levels 2.5-70 times higher than the minimal inhibitory concentration for group B streptococcus. There was no relationship between neonatal ampicillin concentrations and the duration of IAP prior to delivery (β=-0.0003, 95% CI -0.02 to 0.001, p=0.680).

CONCLUSIONS

Ampicillin levels reach a peak in the umbilical cord blood within 30 min of intrapartum administration. After a full loading dose, bactericidal levels persist for at least 4 hours after birth and seem independent of the duration of IAP prior to delivery.

Group B Streptococcal Maternal Colonization and Neonatal Disease: Molecular Mechanisms and Preventative Approaches

Group B Streptococcus (GBS) colonizes the gastrointestinal and vaginal epithelium of a significant percentage of healthy women, with potential for ascending intrauterine infection or transmission during parturition, creating a risk of serious disease in the vulnerable newborn. This review highlights new insights on the bacterial virulence determinants, host immune responses, and microbiome interactions that underpin GBS vaginal colonization, the proximal step in newborn infectious disease pathogenesis. From the pathogen perspective, the function GBS adhesins and biofilms, β-hemolysin/cytolysin toxin, immune resistance factors, sialic acid mimicry, and two-component transcriptional regulatory systems are reviewed. From the host standpoint, pathogen recognition, cytokine responses, and the vaginal mucosal and placental immunity to the pathogen are detailed. Finally, the rationale, efficacy, and potential unintended consequences of current universal recommended intrapartum antibiotic prophylaxis are considered, with updates on new developments toward a GBS vaccine or alternative approaches to reducing vaginal colonization.

Appropriateness of Intrapartum Antibiotic Prophylaxis to Prevent Neonatal Group B Streptococcus Disease

The aims of this study were to describe the adherence to CDC guidelines for intrapartum antibiotic prophylaxis (IAP) and to identify possible factors influencing noncompliance with guidelines. We conducted a retrospective study in Italy. Our cohort included women in whom antenatal Group B Streptococcus (GBS) screening was not performed, was performed, but results were not available at the time of labor or delivery and women who were positive for GBS colonization. The indications for complete execution of IAP according to revised CDC guidelines was evaluated. It was considered adequate when performed with a recommended antibiotic at least four hours prior to delivery. The cohort included 902 women. Among those who had performed rectal and vaginal swabs (or recto-vaginal swabs), results were available in 86.9% of vaginal swabs and in 87.1% of rectal swabs and GBS was detected in 59.8% of vaginal swabs and in 71% of rectal swabs. 49.2% women had indication for GBS prophylaxis. Among these, 91.1% received an antibiotic during labor. Totally appropriate IAP was performed in 36.3% deliveries, an inappropriate antibiotic was administered in 10.4% women, the remaining 45.3% women received partially appropriate IAP; of these, 15.5% had received antibiotics through an inappropriate route of administration, 18.2% an inappropriate dosage regimen. Overall, 27.5% women received intrapartum ampicillin with inappropriate timing. Multivariate analysis showed that totally appropriate prophylaxis was significantly more likely in women who had no previous live birth, who had vaginal delivery, and a positive result at antenatal GBS screening. Despite satisfactory GBS screening implementation, there is still a substantial gap between optimal and actual IAP. We hypothesize that the complexity of the CDC guidelines may partially explain this shortcoming. Future efforts will include initiatives focused at enabling and reinforcing adherence to evidence-based prevention practices.