Babylonia areolate gut ARGs and microbiomes

Cadmium (Cd) is widely distributed in aquatic environment and it has multiple adverse effects on aquatic organisms such as Babylonia areolate. However, its effects on antibiotic resistance genes (ARGs) and microbiota of Babylonia areolate gut are still poorly understood. In this study, we explored the effects of different concentrations (0.03, 0.18 and 1.08 mg/L) of Cd on intestinal microbial communities and ARGs in Babylonia areolate through 16S rRNA gene sequencing and high-throughput quantitative PCR. The results showed that the structure and diversity of ARGs and microbiota were changed by Cd exposure. The absolute abundance and alpha diversity of ARGs in Babylonia areolata gut increased with the rise of cadmium concentration. The microbial communities at genus level enriched in low and medium Cd concentration groups, while decreased in high Cd concentration groups compared to the control groups. In addition. The influence of microbiota on ARG profile was more significant than that of Cd concentration and MGEs in Babylonia areolata gut. Null model analysis demonstrated that stochastic processes dominated ARG assembly in Cd exposure groups and enhanced with the increase of Cd concentration. Four opportunistic bacterial pathogens detected in Babylonia areolata gut maybe the potential hosts of ARGs. Our findings probably provide references for the hazards assessment of environmental Cd exposure towards gut microbiome in aquatic animals.