TY - JOUR T1 - Influence of timing of maternal antibiotic administration during caesarean section on infant microbial colonisation: a randomised controlled trial JF - Gut JO - Gut SP - 1803 LP - 1811 DO - 10.1136/gutjnl-2021-324767 VL - 71 IS - 9 AU - Thomas Dierikx AU - Daniel Berkhout AU - Anat Eck AU - Sebastian Tims AU - Johan van Limbergen AU - Douwe Visser AU - Marjon de Boer AU - Nanne de Boer AU - Daan Touw AU - Marc Benninga AU - Nine Schierbeek AU - Laura Visser AU - Jan Knol AU - Guus Roeselers AU - Johanna de Vries AU - Tim de Meij Y1 - 2022/09/01 UR - http://gut.bmj.com/content/71/9/1803.abstract N2 - Objective Revised guidelines for caesarean section (CS) advise maternal antibiotic administration prior to skin incision instead of after umbilical cord clamping, unintentionally exposing the infant to antibiotics antenatally. We aimed to investigate if timing of intrapartum antibiotics contributes to the impairment of microbiota colonisation in CS born infants.Design In this randomised controlled trial, women delivering via CS received antibiotics prior to skin incision (n=20) or after umbilical cord clamping (n=20). A third control group of vaginally delivering women (n=23) was included. Faecal microbiota was determined from all infants at 1, 7 and 28 days after birth and at 3 years by 16S rRNA gene sequencing and whole-metagenome shotgun sequencing.Results Compared with vaginally born infants, profound differences were found in microbial diversity and composition in both CS groups in the first month of life. A decreased abundance in species belonging to the genera Bacteroides and Bifidobacterium was found with a concurrent increase in members belonging to the phylum Proteobacteria. These differences could not be observed at 3 years of age. No statistically significant differences were observed in taxonomic and functional composition of the microbiome between both CS groups at any of the time points.Conclusion We confirmed that microbiome colonisation is strongly affected by CS delivery. Our findings suggest that maternal antibiotic administration prior to CS does not result in a second hit on the compromised microbiome. Future, larger studies should confirm that antenatal antibiotic exposure in CS born infants does not aggravate colonisation impairment and impact long-term health.Data are available upon reasonable request. The study protocol was published online (doi: 10.1186/s13063-019-3552-8.). The generated raw sequence datasets and deidentified participant data is available on reasonable request from the corresponding author TD. ER -