Yamashita Naoyuki, Katakawa Yohei, Tanaka Hiroaki
Research Center for Environmental Quality Management, Graduate School of Engineering, Kyoto University, 1-2 Yumihama, Otsu, Shiga 520-0811, Japan.
Research Center for Environmental Quality Management, Graduate School of Engineering, Kyoto University, 1-2 Yumihama, Otsu, Shiga 520-0811, Japan.
Ecotoxicol Environ Saf. 2017 Sep;143:38-45. doi: 10.1016/j.ecoenv.2017.04.053. Epub 2017 May 9.
Antimicrobial resistant bacteria are widespread in aquatic environments. The aim of the present study was to obtain information on the occurrence of bacteria with antimicrobial resistance and their multiple antimicrobial resistance (MAR) patterns in a river basin in Japan. In addition, the occurrence of fecal bacteria producing extended-spectrum beta-lactamases (ESBLs) and metallo-beta-lactamase (MBL) in the aquatic environment was determined. Among the Escherichia coli isolates recovered from river samples upstream, 55% isolates were resistant to at least one antimicrobial and 18% were MAR. Among the E. coli isolates recovered from wastewater treatment plant (WWTP) effluent samples, 74% isolates were resistant to at least one antimicrobial and 46% were MAR. These findings suggest that the presence of WWTP effluent will increase the degree of contamination with MAR in the aquatic environment. Among the ampicillin-resistant isolates recovered from river samples, 21% isolates were judged as ESBL-producing and none (0%) was judged as MBL-producing. Among the ampicillin-resistant isolates recovered from WWTP effluent samples, 21% were judged as ESBL-producing and 1% was judged as MBL-producing. As for the hospital wastewater samples, 48% were judged as ESBL-producing and 3% were judged as MBL-producing. The percentage of ESBLs and MBL production was highest in hospital wastewater samples. All of the ESBL-producing isolates detected had resistance to ampicillin, cephazolin, and cefpodoxime and many ESBL-producers had resistance not only to beta-lactams but also to other kinds of antimicrobials such as aminoglycosides and quinolones. The frequency of detection of MBL-producers was much lower than that of ESBL-producers and MBL-producers were not detected in the river samples. However, the detection in WWTP effluent samples indicated that bacteria with MBL were present downstream of the WWTP at low concentrations. Thus, ESBLs and MBL have already been spread around aquatic environments.
耐抗菌药物细菌在水生环境中广泛存在。本研究的目的是获取日本某流域中具有抗菌药物耐药性的细菌及其多重抗菌药物耐药（MAR）模式的发生情况信息。此外，还测定了水生环境中产生超广谱β-内酰胺酶（ESBLs）和金属β-内酰胺酶（MBL）的粪便细菌的发生情况。从上游河流样本中分离出的大肠杆菌菌株中，55%的菌株对至少一种抗菌药物耐药，18%为多重耐药。从污水处理厂（WWTP）出水样本中分离出的大肠杆菌菌株中，74%的菌株对至少一种抗菌药物耐药，46%为多重耐药。这些发现表明，污水处理厂出水的存在会增加水生环境中多重耐药污染的程度。从河流样本中分离出的耐氨苄西林菌株中，21%的菌株被判定为产ESBLs，无一（0%）被判定为产MBL。从污水处理厂出水样本中分离出的耐氨苄西林菌株中，21%被判定为产ESBLs，1%被判定为产MBL。至于医院废水样本，48%被判定为产ESBLs，3%被判定为产MBL。医院废水样本中产ESBLs和MBL的百分比最高。所有检测到的产ESBLs菌株均对氨苄西林、头孢唑林和头孢泊肟耐药，许多产ESBLs菌株不仅对β-内酰胺类耐药，还对其他种类的抗菌药物如氨基糖苷类和喹诺酮类耐药。产MBL菌株的检测频率远低于产ESBLs菌株，且在河流样本中未检测到产MBL菌株。然而，在污水处理厂出水样本中的检测表明，产MBL的细菌以低浓度存在于污水处理厂下游。因此，ESBLs和MBL已经在水生环境中传播开来。
