Asymptomatic term infants may not routinely need empirical antibiotic therapy: Study

Maternal chorioamnionitis is a well established risk factor for Neonatal Early Onset Sepsis(EOS) and EOS may lead to significant morbidity and mortality. Based on the guidelines by the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP),the current approach for all infants exposed to maternal chorioamnionitis is to undertake limited diagnostic evaluation and administer empirical intravenous antibiotic treatment even when asymptomatic.

Researchers from University of Sydney Australia studied 7736 mother infants dyads and found that asymptomatic infants monitored in hospital for 48 hours without commencing antibiotics had similar outcomes to those who received antibiotics.

In this study a total of 167 infants were born to chorioamnionitis mothers.Maternal chorioamnionitis was clinically diagnosed based on the presence of body temperature higher than 38 degrees Centigrade, fetal heart rate more than 160 beats per minute, maternal heart rate more than 100 beats per minute, uterine tenderness, and offensive amniotic fluid. All the mothers suspected of chorioamnionitis received adequate intrapartum IV antibiotic therapy. At risk Infants received empirical treatment with intravenous penicillin and gentamicin until EOS was excluded.

Researchers found that the incidence of chorioamnionitis was 21 per 1000 deliveries and 89% of women received intrapartum antibiotics. A positive placental swab culture was reported in 17% mothers and histopathological chorioamnionitis seen in 63% mothers. The most common pathogens in positive placental cultures were GBS (n = 9) followed by Escherichia coli (n = 8). Of the positive blood cultures, two were positive for Escherichia coli (n = 2) and two were possibly contaminants (Gardnerella vaginalis and Atopobium vaginae).

Out of 167 infants born to chorioamnionitis mothers, 24% (40 infants) were symptomatic with varied presentation- 15% had congenital pneumonia (with clinical symptoms and radiological evidence), 7% had transient tachypnoea of the newborn, and 15% had a pneumothorax. All the asymptomatic infants also received IV antibiotics till the culture report was negative(atleast 48 hours of life).

The key finding of the study is that –" none of the term infants exposed to maternal chorioamnionitis had culture-proven sepsis." Asymptomatic infants (76%) received intravenous antibiotics for an average of two days compared to four days in the symptomatic group (24%), P < 0.001.

Over the last 20 years, the incidence of early-onset GBS sepsis has declined dramatically with the use of intrapartum antibiotic prophylaxis(IAP) and a only a small proportion of infants born to chorioamniotis mothers develop EOS. Studies in the last decade have reported a very low risk of EOS and a high use of empirical intravenous antibiotics in asymptomatic infants.Serial clinical monitoring of at-risk infants has shown significant decreases in the use of laboratory testing and empirical antibitics use in a review of 400000 neonates. The disadavntes of empirical antibiotic therapy include potential alteration of gut microbiome, maternal-infant separation and increased healthcare costs.

Authors conclude –"Updated treatment guidelines are needed to optimise clinical management for these infants and the practice of empirical antibiotic use in wellappearing infants exposed to chorioamnionitis needs to be reviewed".

Source:Acta pediatrica