metagenomics and corpse decomposition

Climate warming multiplies the threat of antibiotic resistance genes (ARGs) to public health, but the responses of resistome in water to temperature change after cadaver decomposition remain unknown. Here, by metagenomic sequencing, we investigated the changes of resistome at five different temperature gradients (23, 26, 29, 32, and 35 ?) in polluted water by animal cadaver. Thirty ARG types including 668 subtypes were observed in our samples. Temperature significantly influenced ARG profiles and had a negative correlation with ARG diversity. The ARG assembly process was dominated by deterministic processes (63.32% - 95.08%) but showed a peak pattern with temperature. Notably, temperature may predict approximately 21% of ARGs, while most other ARGs were insensitive to temperature. Three types (carbapenem, dicyclomycin, and diaminopyrimidine antibiotic) and 63 subtypes of ARGs that positively correlated with temperature were identified in polluted water by carcass. Proteobacteria, Actinobacteria, and Bacteroidetes were the main hosts of ARGs, carrying 562, 250, and 200 ARG subtypes, respectively. Notably, we screened 21 subtypes of high-risk ARGs (bacA, mdtA, tetM, etc.) and 22 opportunistic pathogens (Aeromonas, Clostridium, Bacteroides, etc.) and found their positive co-occurrence with temperature, implying these potential biological or genetic pollutants may probably go up under global warming. Our study reveals the predictability and health risks of resistome to temperature change, providing a suitable way to track the fate and spread of ARGs in polluted water under climate warming.