The gut resistome is highly dynamic during the first months of life

Aim: We investigated the longitudinal development of several antibiotic resistance genes (ARGs) of the infant gut resistome during the first months after birth. Materials & methods: Fecal samples from 120 infants collected at the ages of 5, 13 and 31 weeks were analyzed and subjected to qPCR for the detection of several ARGs. Results: The prevalence of ARGs significantly increased for ermB, tetM and tetQ, while it decreased for aac(6')-aph(2'). Birth mode and breastfeeding significantly affected tetQ prevalence. Correlations to bacterial taxa suggest that fluctuations in some ARGs are (partly) attributed to shifts in bacteroides colonization rates. Conclusion: Acquisition of ARGs in the gut microbiota occurs shortly after birth and resistome composition fluctuates over the course of several months, reflecting changes in microbial community structure.