Low Concentration Antibiotic Exposure and Horizontal Gene Transfer in Zebrafish Gut Microbiome

Abstract

Antibiotic resistance is a major global health concern driven by horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs). Oxytetracycline (OTC) and low concentrations of other antibiotics in the ecosystem can subtly affect microbial environment and perhaps stimulate the HGT events. This study highlights the impact of low concentrations of OTC on HGT within the zebrafish gut microbiome. Zebrafish were exposed to low concentrations of OTC, and metagenomics analysis was conducted, including assembly using MEGAHIT, HGT identification by WAAFLE, and functional annotations with eggNOG-mapper. Significant increase in HGT frequency and shifts in microbial community structure were observed in OTC group. Key findings include the identification of the catB2 gene, associated with chloramphenicol resistance, with 73.4% similarity. Comparative analyses revealed distinct HGT patterns, including the transfer of ARGs, virulence factors, and metabolic pathways. Additionally, analyses explored significant increase in the opportunistic pathogens, such as that belong to the Proteobacteria phylum. These pathogens penetrate and cause dysbiosis in the host’s gut microbiome via HGT, rendered it easier to acquire virulence factors. These findings highlight the thoroughly impact of low concentrations of antibiotics on HGT and microbial ecology within the zebrafish gut microbiome, emphasizing the necessity to encompassed the environmental antibiotic pollution to mitigate the propagation of antibiotic resistance.