Intrapartum antibiotic prophylaxis for women who are screened positive for group B streptococcal colonisation: Clinical compliance with the guideline

BACKGROUND

In high income countries, ~30% of pregnant women are provided with intrapartum antibiotic prophylaxis (IAP) for early-onset group B streptococcal infection (EOGBSI). The infection rate is low, 0.2/1000 livebirths in our jurisdiction, and others. We hypothesised factors, other than IAP alone, were reasons for the low rate of EOGBSI.

AIMS

Compliance with our local guideline, referred to here as 'the guideline'.

METHOD

Compliance was defined as an initial dose of benzylpenicillin IAP followed by four-hourly doses until birth. The study population was drawn from 4098 women who had 4100 pregnancies resulting in 4200 babies in an Australian birth setting from 1/1/2016 to 31/12/2016. Most, 93%, were eligible for universal GBS screening, 67% were reported as screened and 90% of these had a result documented; 23% were positive for GBS. A random sample (n = 223) was taken for further analysis.

RESULTS

The adjusted odds of receiving benzylpenicillin IAP in accord with the guideline were three times higher among primiparous compared to multiparous women (P < 0.001, odds ratio (OR) = 3.4, 95% CI 1.7-6.7) and three times higher among women experiencing induction of labour compared to women who commenced labour spontaneously (P < 0.001, OR = 3.4, 95% CI 1.8-6.3). Of the 223 women, 188 received IAP: 176 received benzylpenicillin IAP, 31% (or 24% of the total sample) received this intervention in accord with the guideline, 24% received benzylpenicillin ≥4 h before birth but not in accord with the guideline and 44% received benzylpenicillin <4 h before birth.

CONCLUSION

We conclude that sub-optimal compliance was largely a consequence of an unrealistic guideline.

Epidemiology of neonatal early-onset sepsis in a geographically diverse Australian health district 2006-2016

AIM

To describe the epidemiology of EOS including blood culture utilisation, across a large and geographically diverse Australian health district.

BACKGROUND

Sepsis in the first three days of life remains a leading cause of death and morbidity. In high-income countries, group B Streptococcus (GBS) and Escherichia coli (E. coli) have dominated as causes of EOS for five decades.

METHOD

An 11-year retrospective cohort study to determine the epidemiology of EOS. Incidence rates were calculated per 1000 live births. Logistic regression with linear temporal trend and covariates for potential effect modifiers were employed. Blood culture utilisation was determined by examining the rate of babies undergoing blood culture within 72 hours of birth.

RESULTS

Among 93,584 live born babies, 65 had confirmed EOS (0.69/1000 live births); 22 term, 43 preterm. Across the 4 largest birth units, the proportion of babies having blood culture within 72 hours of birth varied from 1.9-5.1% for term and 21-35% for preterm babies. The annual change in the EOS rate was significant, OR 0.91 (95% CI, 0.84 to 0.99, p = 0.03). Group B Streptococcus was the most common cause of EOS in term neonates at 0.35/1000 live births (95% CI, 0.07-0.63) in 2006 and 0.1/1000 live births (95% CI, 0-0.2) in 2016. Escherichia coli was the most common cause in preterm babies at 3.4/1000 (95% CI, 0.11-6.76) in 2006 reducing significantly to 1.35/1000 live births (95% CI, -0.07-2.78) by 2016.

CONCLUSIONS

Escherichia coli and GBS were the most common causes of EOS in preterm and term babies respectively. Rates of all cause term and preterm EOS declined significantly as did preterm sepsis due to E. coli. While rate of sepsis due to early-onset GBS declined, this did not reach significance. Given the high proportion of preterm babies undergoing blood culture, it is unlikely that any EOS events were missed.

Group B streptococcal screening, intrapartum antibiotic prophylaxis, and neonatal early-onset infection rates in an Australian local health district: 2006-2016

Background

Intrapartum antibiotic prophylaxis (IAP) to reduce the likelihood of neonatal early-onset group B streptococcal infection (EOGBS) has coincided with major reductions in incidence. While the decline has been largely ascribed to IAP following either universal screening or a risk-based approach to identify mothers whose babies may most benefit from IAP, there is lack of high quality evidence to support this view.

Aims

To describe management of maternal GBS colonisation in one local health district using universal screening and assess rates of EOGBS over time.

Methods

A retrospective cohort study was undertaken to describe compliance with GBS management, to determine the incidence of EOGBS and association between rates and maternal screening. Linking routinely collected maternity and pathology data, we explored temporal trends using logistic regression and covariates for potential effect modifiers.

Results

Our cohort included 62,281 women who had 92,055 pregnancies resulting in 93,584 live born babies. Screening occurred in 76% of pregnancies; 69% had a result recorded, 21.5% of those were positive for GBS. Prophylaxis was used by 79% of this group. Eighteen babies developed EOGBS, estimated incidence/1000 live births in 2006 and 2016 was 0.35 (95% CI, 0.07 to 0.63) and 0.1 (95% CI, 0 to 0.2) respectively. Seven of 10 term babies with EOGBS were born to mothers who screened negative. Data were unable to provide evidence of difference in rates of EOGBS between screened and unscreened pregnancies. We estimated the difference in EOGBS incidence from crude and weighted models to be 0 (95% CI, -0. 2 to 0.17) and -0.01 (95% CI, -0.13 to 0.10) /1000 live births respectively.

Conclusion

No change was detected in rates of EOGBS over time and no difference in EOGBS in babies of screened and unscreened populations. Screening and prophylaxis rates were modest. Limitations of universal screening suggest alternatives be considered.

Effectiveness of intrapartum antibiotic prophylaxis for early-onset group B Streptococcal infection: An integrative review

BACKGROUND

In some countries, up to 30% of women are exposed to intrapartum antibiotic prophylaxis for prevention of early-onset group B Streptococcal infection. Intrapartum antibiotic prophylaxis aims to reduce the risk of neonatal morbidity and mortality from this infection. The intervention may adversely affect non-pathogenic bacteria which are passed to the newborn during birth and are considered important in optimising health. Since many women are offered intrapartum antibiotic prophylaxis, effectiveness and implications of this intervention need to be established. This review considers clinical trials and observational studies analysing the effectiveness of intrapartum antibiotic prophylaxis.

METHODS

An integrative literature review was conducted. One systematic review, three clinical trials and five observational studies were identified for appraisal.

FINDINGS

Randomised controlled trials found intrapartum antibiotic prophylaxis effective but all retrieved randomised clinical trials had significant methodological flaws. High quality observational studies reported high rates of effectiveness but revealed less than optimal adherence to screening and administration of the prophylaxis. Scant consideration was given to short term risks, and long-term consequences were not addressed.

DISCUSSION

Studies found intrapartum antibiotic prophylaxis to be effective. However, evidence was not robust and screening and prophylaxis have limitations. Emerging evidence links intrapartum antibiotic prophylaxis to adverse short and longer-term neonatal outcomes.

CONCLUSION

Our review found high quality evidence of the effectiveness of intrapartum antibiotic prophylaxis was limited. Lack of consideration of potential risks of the intervention was evident. Women should be enabled to make informed decisions about GBS management. More research needs to be done in this area.