Adherence to universal screening for group B Streptococcus in pregnancy and prevalence of colonised pregnancies in Caserta province, Italy.

Abstract

Group B Streptococcus (Streptococcus agalactiae; GBS) infection is a significant contributor to neonatal morbidity and mortality. In the early 1970s, the neonatal mortality rate for infants with invasive GBS disease was 55%. With the adoption of the first medical community guidelines to prevent GBS infection in the 1990s, the mortality rate decreased to approximately 5%. The main obstetric procedure for preventing vertical transmission of GBS infection involves universal screening of pregnant women using a vaginal-rectal swab (VRS) to identify those eligible for intrapartum antibiotic prophylaxis (IAP). The study analyzes the adherence of screening and the trend of GBS infection in pregnancy in the province of Caserta, Italy. Data were obtained from pregnant women who gave birth in a first level birthing center in 2022 from birth assistance certificate (CEDAP), obstetric and neonatal record. Postnatal evaluation collected through computer-assisted telephone interviews. 567 women delivered at our center during the study period. The average coverage of GBS testing in pregnancy was 99.2% (562), and the proportion of GBS colonised women was 12.6% (71) according with the national average, which is about 10-20%. The spread of positive cases appears to fluctuate among the various groups of pregnant women studied, indicating no significant statistical variance among presence of a partner, among women who have given birth multiple times, among Italian nationals, or across different ages, but a significant statistical excess is evident among mothers with less education. In 93% (66) of GBS carrier mothers, intrapartum antibiotic prophylaxis (IAP) was administered correctly, regardless of the type of delivery performed. Despite the successful integration of GBS screening, a significant gap remains between the ideal scenario and the actual implementation of IAP. At the three-month assessment, no child required hospitalization, consistent with the relatively low incidence of invasive GBS infection. Nevertheless, for those who are not eligible to VRS screening, such as preterm birth, or IAP, as in precipitous birth, the identification of biomarkers enabling early recognition of invasive GBS disease remains essential. Additionally, the emergence of vaccines administered during gestation, conferring passive immunity to newborns represents a promising possible new direction. Therefore, to ensure the practical application of GBS screening and actual IAP by healthcare providers, periodic audits and regular monitoring should be encouraged.