摘要

       本研究采用高通量定量 PCR 和 16S rRNA 测序来评估温度和残留抗生素对猪粪厌氧消化过程中抗生素抗性基因 (ARG) 和微生物群落动态的影响。总 ARGs 和 16S rRNA 基因的丰度在所有四种处理（25°C、37°C 和 37°C，50 mg 体重湿重抗生素和 55°C）中均显着降低。大多数ARG类型的丰度与16S rRNA基因和转座酶基因的丰度显着相关（P < 0.01）。然而，55°C 下总 ARG 的丰度远高于其他处理。同时，55°C下的微生物群落，其中链球菌病原体保持相对较高的丰度，纤维素降解剂和产氢者（如乙醇菌和粪球菌）增加，与其他处理显着不同。冗余分析表明，温度、pH 和链球菌属分别对实验因素、化学性质和代表性属之间的 ARG 变异有最高的解释。网络分析进一步表明，链球菌属对 55°C 下较高的 ARG 丰度有很大贡献。适度的抗生素残留仅对微生物多样性种群造成轻微和短暂的抑制，并促进 ARG 丰度，这可能是由于抗生素的降解和微生物的适应性。我们的结果阐明了基因转移相关项目对 ARG 变异的协同作用，并集中证明，除非更有效地抑制病原体和基因转移元件，否则较高的温度并不总是能在厌氧消化中实现更好的 ARG 去除。

       This study employed high-throughput quantitative PCR and 16S rRNA sequencing to evaluate the effect of temperature and residual antibiotics on the dynamics of antibiotic resistance genes (ARGs) and microbial communities during anaerobic digestion of swine manure. The abundances of total ARGs and 16S rRNA genes significantly decreased in all of four treatments (25°C, 37°C, and 37°C with 50 mg of wet weight antibiotics of body weight, and 55°C). The abundances of most ARG types were significantly correlated with those of the 16S rRNA gene and transposase gene (P < 0.01). However, the abundances of total ARGs at 55°C were much higher than those of other treatments. Meanwhile, the microbial communities at 55°C, where the Streptococcus pathogen remained at a relatively high abundance and cellulose degraders and hydrogen producers, such as Ethanoligenens and Coprococcus bacteria, increased, were markedly different from those of other treatments. Redundancy analysis indicates that temperature, pH, and the genus Streptococcus had the highest explanation for ARG variation among experimental factors, chemical properties, and representative genera, respectively. Network analysis further showed that the genus Streptococcus contributed greatly to the higher ARG abundance at 55°C. The moderate antibiotic residue only caused a slight and transitory inhibition for microbially diverse populations and promotion for ARG abundance, probably due to the degradation of antibiotics and microbial adaptability. Our results clarify the cooperativity of gene transfer-related items on ARG variation and intensively prove that higher temperature cannot always achieve better ARG removal in anaerobic digestion unless pathogens and gene transfer elements are more efficiently inhibited.