BackgroundAgainst a background of failure to prevent neonatal invasive early-onset group B Streptococcus infections (GBS) in our maternity unit using risk-based approach for intrapartum antibiotic prophylaxis, we introduced an antenatal GBS carriage screening programme to identify additional women to target for prophylaxis.ObjectivesTo describe the implementation and outcome of an antepartum screening programme for prevention of invasive early-onset GBS infection in a UK maternity unit.DesignObservational study of outcome of screening programme (intervention) with comparison to historical controls (preintervention).SettingHospital and community-based maternity services provided by Northwick Park and Central Middlesex Hospitals in North West London.ParticipantsWomen who gave birth between March 2014 and December 2015 at Northwick Park Hospital.MethodsWomen were screened for GBS at 35–37 weeks and carriers offered intrapartum antibiotic prophylaxis. Screening programme was first introduced in hospital (March 2014) and then in community (August 2014). Compliance was audited by review of randomly selected case records. Invasive early-onset GBS infections were defined through GBS being cultured from neonatal blood, cerebrospinal fluid or sterile fluids within 0–6 days of birth.Main outcomeIncidence of early-onset GBS infections.Results6309 (69%) of the 9098 eligible women were tested. Screening rate improved progressively from 42% in 2014 to 75% in 2015. Audit showed that 98% of women accepted the offer of screening. Recto-vaginal GBS carriage rate was 29.4% (1822/6193). All strains were susceptible to penicillin but 11.3% (206/1822) were resistant to clindamycin. Early onset GBS rate fell from 0.99/1000 live births (25/25276) in the prescreening period to 0.33/1000 in the screening period (Rate Ratio=0.33; p=0.08). In the subset of mothers actually screened, the rate was 0.16/1000 live births (1/6309), (Rate Ratio=0.16; p<0.05).ConclusionsOur findings confirm that an antenatal screening programme for prevention of early-onset GBS infection can be implemented in a UK maternity setting and is associated with a fall in infection rates.

ObjectivesTo describe the impact on early-onset group B Streptococcus (EOGBS) infection rates following reversion from screening-based to risk-based intrapartum antimicrobial prophylaxis (IAP) for prevention.SettingMaternity services provided by secondary healthcare organisation in North West London.ParticipantsAll women who gave birth in the healthcare organisation between April 2016 and March 2017. There were no exclusions.DesignObservational study comparing EOGBS rates in the postscreening period (2016–2017) with prescreening (2009–2013) and screening periods (2014–2015).MethodsLocal guidelines for risk-based IAP were reintroduced in April 2016. Compliance with guidelines was audited. Gestational age, mode of delivery, maternal demographics and EOGBS rates in three time periods were compared using Poisson regression analysis. EOGBS was defined through GBS being cultured from blood, cerebrospinal fluid or other sterile fluids within 6 days of birth.Primary outcomeEOGBS rates/1000 live births in prescreening, screening and postscreening periodsResultsIncremental changes in maternity population were observed throughout the study period (2009 onwards), in particular the ethnic profile of mothers. Of the 5033 live births in postscreening period, 9 babies developed EOGBS infection. Only one of the mothers of affected babies had a risk factor indicating use of IAP. Comparison of postscreening period with screening period showed a fivefold increase in EOGBS rates after adjustment for ethnicity (1.79 vs 0.33/1000 live births; risk ratio =5.67, p=0.009). There was no significant difference between prescreening and postscreening periods with rates of infection reverting to their prescreening level.ConclusionsThis study provides further evidence of efficacy of screening-based IAP compared with risk-based IAP in prevention of EOGBS in newborns in an area of high incidence.