Influence of Cefuroxime on Gut Microbiota Composition at Very Early Exposure of Infants Born by Caesarean Section

Objectives: It is standard caesarean section (CS) procedure in many hospitals to administer the mother a single prophylactic dose of cefuroxime shortly before skin incision. This procedure prevents infection of the mother's incision wound, but the foetus is also exposed to the antibiotic. Here we investigate whether this very early exposure to antibiotics influence gut microbiota (GM) colonization and antibiotic susceptibility of the gut bacteria in the new-born. Methods: Forty-two pregnant women (BMI<30) scheduled for elective CS were recruited at Odense University Hospital, Denmark, and randomly assigned to receive cefuroxime either before skin incision or immediately after the umbilical cord was cut. Faecal samples were collected from all infants at 10 days and 9 months of age. GM composition was determined by 16S rRNA gene amplicon high throughput sequencing. Gram-positive cocci and Enterobacteriaceae were cultured and isolates identified by MALDI-TOF before antimicrobial susceptibility tests were performed by the Kirby-Bauer disk diffusion technique. Results: No clear differences in the GM composition were observed between infants whose mothers received cefuroxime before or after CS at neither time point, though surprisingly at 9 months of age, but not at 10 days of age, the number of observed species were higher in the infants where the mothers received cefuroxime after cord clamping. No differences in antimicrobial susceptibility of Enterobacteriaceae, Enterococcus spp., and Staphylococcus spp. were seen at 10 days between the two intervention groups.