Gut resistomes, microbiota and antibiotic residues in Chinese patients undergoing antibiotic administration and healthy individuals.

Human gut microbiota is an important reservoir of antibiotic resistance genes (ARGs). Although dysbacteriosis after the antibiotic course has been previously observed in the patient guts, a comprehensive comparison of gut resistomes, microbiota and antibiotic residues in healthy individuals and patients undergoing antibiotic administration is little. Using high-throughput qPCR, 16S rRNA gene amplicon sequencing and UPLC-MS/MS, we systematically examined the antibiotic resistome, gut microbiota, and antibiotic residues in fecal samples from both Chinese healthy individuals and patients receiving antibiotic therapy. Compared with healthy individuals, patients' guts harbored lower diverse gut resistome and microbiota, but higher concentrations of antibiotics and ARGs. Antibiotic concentration in human guts was positively correlated with ARG total abundance, but was negatively related to the diversity of both ARGs and bacterial communities, which demonstrated that antibiotic administration could shape the antibiotic resistomes and bacterial communities in the patient guts. Gene cfxA was evaluated as a potential biomarker to distinguish the patients receiving antibiotic therapy from the healthy individuals in China since its wide detection and significant enrichment in the guts of the patients. The detection of some veterinary antibiotics in human guts illustrated the potential transmission of antibiotic from the external environment to human via the food chain. The obtained results could help to better understand the influence of antibiotic therapy in shaping antibiotic reistomes and bacterial communities in Chinese individuals.