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.
