Li Hui-Li, Pei Yuan-Mei, Li Shan, He Fu-Rong, Yang Yue-Ting, Wei Yuan-Song, Tong Juan
School of Civil Engineering, Lanzhou University of Technology, Lanzhou 730050, China.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Huan Jing Ke Xue. 2019 Jul 8;40(7):3270-3275. doi: 10.13227/j.hjkx.201812127.
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.
城市污泥含有大量肠球菌，这些肠球菌可能携带抗生素抗性基因（ARGs）和毒力基因（VGs）。因此，含有ARG和VG的肠球菌具有潜在的抗性和毒力，对人类健康构成重大风险。因此，研究了从热解污泥的中温（40℃）和高温（55℃）厌氧消化中分离出的肠球菌的抗性表型以及肠球菌中ARGs和VGs的流行情况。结果表明，从热解污泥中分离出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。高温厌氧消化导致肠球菌丰度的更大降低（分别降低两个数量级和一个数量级），以及肠球菌抗生素抗性率的更大降低。然而，高温消化可促进肠球菌中四环素抗性基因的表达。此外，中温和高温消化均可促进肠球菌之间的水平基因转移（HGT），这可能导致双重或多重抗性的发生率增加。中温消化降低了肠球菌中共存的ARGs和VGs的流行率，而高温消化则产生相反的效果。这项研究增进了对城市污泥处理过程中潜在病原体中ARGs和VGs的发生和归宿的理解。
