摘要

这项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。在所有四种治疗中（使用50 mg体重的湿重抗生素和55°C的25°C，37°C和37°C的所有处理），总ARGs和16S rRNA基因的丰度都显着降低。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）。但是，55°C时总ARG的丰度远高于其他处理。同时，链球菌病原体仍保持较高丰度，而纤维素降解物和产氢物质（如乙醇单核菌属和副链球菌）的55℃温度下的微生物群落与其他处理明显不同。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中的ARG变异具有最高解释。网络分析进一步表明，链球菌属在55°C时对较高的ARG丰度有很大贡献。中度的抗生素残留仅对微生物多样性人群造成了轻微的短暂抑制，并提高了ARG的含量，这可能是由于抗生素的降解和微生物的适应性所致。我们的研究结果阐明了与基因转移相关的项目在ARG变异方面的协同作用，并充分证明，除非更有效地抑制病原体和基因转移元件，否则高温在厌氧消化中不能始终获得更好的ARG去除效果。

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.

https://aem.asm.org/content/85/7/e02878-18.abstract