摘要

       城市污泥中含有大量的肠球菌，可携带抗生素耐药基因（ARGs）和毒力基因（VGs）。因此，含有ARG-和VG的肠球菌具有潜在的耐药性和毒力，因此对人类健康构成重大威胁。因此，研究了热水解污泥中温（40℃和55℃厌氧消化分离的肠球菌的耐药表型及ARGs和VGs在肠球菌中的分布。结果表明，从热水解污泥中分离得到的肠球菌对阿奇霉素的抗性明显高于对螺旋霉素和四环素的抗性。嗜热厌氧消化导致肠球菌丰度大幅度降低（分别降低2个数量级和1个数量级），肠球菌对抗生素的耐药率也大幅度降低。高温消化可促进肠球菌四环素抗性基因的表达。此外，嗜中温消化和嗜热消化都能促进肠球菌之间的水平基因转移（HGT），这可能导致双抗或多抗的发生。中温消化降低了肠球菌中共存ARGs和VGs的发生率，而高温消化则相反。本研究有助于了解城市污泥处理过程中潜在致病菌中ARGs和VGs的发生和去向。

        Municipal sludge contains large amounts of enterococci, which can harbor antibiotic resistance genes (ARGs) and virulence genes (VGs). ARG- and VG-containing enterococci therefore present potential resistance and virulence and, as a consequence, represent a significant health risk to humans. Therefore, the resistance phenotype of enterococci and the prevalence of ARGs and VGs in the enterococci isolated from the mesophilic (40℃) and thermophilic (55℃) anaerobic digestion of thermal hydrolyzed sludge was investigated. Results showed that the enterococci isolated from thermal hydrolyzed sludge showed significantly higher resistance to azithromycin than that to spiramycin and tetracycline. Thermophilic anaerobic digestion resulted in a greater reduction of enterococci abundance (by two orders of magnitude and one order of magnitude, respectively), and a greater reduction in the antibiotic resistance rates of the enterococci. However, thermophilic digestion can promote the expression of tetracycline resistance genes in the enterococci. Furthermore, both mesophilic and thermophilic digestion can facilitate horizontal genes transfer (HGT) between enterococci, which might result in an increase in the occurrence of double- or multiple-resistance. Mesophilic digestion reduced the prevalence of co-occurring ARGs and VGs in enterococci, while thermophilic digestion had the opposite effect. This research improves understanding of the occurrence and fate of ARGs and VGs in potential pathogens during the treatment of municipal sludge.

         https://www.ncbi.nlm.nih.gov/pubmed/31854728