a Departamento de Ambiente, CERNAS , Escola Superior Agraria do Instituto Politécnico de Coimbra , Coimbra , Portugal.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2015;50(1):26-39. doi: 10.1080/10934529.2015.964602.
Antibiotics have been intensively used over the last decades in human and animal therapy and livestock, resulting in serious environmental and public health problems, namely due to the antibiotic residues concentration in wastewaters and to the development of antibiotic-resistant bacteria. This study aimed to access the contribution of some anthropological activities, namely urban household, hospital and a wastewater treatment plant, to the spread of antibiotic resistances in the treated wastewater released into the Mondego River, Coimbra, Portugal. Six sampling sites were selected in the wastewater network and in the river. The ampicillin-resistant Enterobacteriaceae of the water samples were enumerated, isolated and phenotypically characterized in relation to their resistance profile to 13 antibiotics. Some isolates were identified into species level and investigated for the presence of class A and class C -lactamases. Results revealed high frequency of resistance to the -lactam group, cefoxitin (53.5%), amoxicillin/clavulanic acid combination (43.5%), cefotaxime (22.7%), aztreonam (21.3) cefpirome (19.2%), ceftazidime (16.2%) and to the non--lactam group, trimethoprim/sulfamethoxazol (21.1%), tetracycline (18.2%), followed by ciprofloxacin (14.1%). The hospital effluent showed the higher rates of resistance to all antibiotic, except two (chloramphenicol and gentamicin). Similarly, higher resistance rates were detected in the wastewater treatment plant (WWTP) effluent compared with the untreated affluent. Regarding the multidrug resistance, the highest incidence was recorded in the hospital sewage and the lowest in the urban waste. The majority of the isolates altogether are potentially extended-spectrum -lactamases positive (ESBL(+)) (51.9%), followed by AmpC(+) (44.4%) and ESBL(+)/AmpC(+) (35.2%). The most prevalent genes among the potential ESBL producers were blaOXA (33.3%), blaTEM (24.1%) and blaCTX-M (5.6%) and among the AmpC producers were blaEBC (38.9%), blaFOX (1.9%) and blaCIT (1.9%). In conclusion, the hospital and the WWTP activities revealed to have the highest contribution to the spread of multidrug resistant bacteria in the study area. Such data is important for future management of the environmental and public health risk of these contaminants. This is the first embracing study in the water network of Coimbra region on the dissemination of antibiotic resistance determinants. Moreover, it is also the first report with the simultaneous detection of multiresistant bacteria producers of AmpC and ESBLs -lactamases in aquatic systems in Portugal.
抗生素在过去几十年中被广泛应用于人类和动物治疗以及畜牧业中，导致了严重的环境和公共卫生问题，主要是由于废水中抗生素残留浓度以及抗生素耐药菌的产生。本研究旨在评估一些人类活动（城市家庭、医院和污水处理厂）对葡萄牙蒙德古河经处理后的废水中抗生素耐药性传播的贡献。在废水网络和河流中选择了六个采样点。对水样中的氨苄青霉素耐药肠杆菌科进行了计数、分离和表型特征分析，以确定其对 13 种抗生素的耐药谱。对一些分离株进行了种水平鉴定，并研究了它们是否携带 A 类和 C 类 -内酰胺酶。结果显示，-内酰胺类药物（头孢西丁 53.5%、阿莫西林/克拉维酸联合制剂 43.5%、头孢噻肟 22.7%、氨曲南 21.3%、头孢吡肟 19.2%、头孢他啶 16.2%）和非 -内酰胺类药物（甲氧苄啶/磺胺甲恶唑 21.1%、四环素 18.2%）对 -内酰胺类药物的耐药率较高，其次是环丙沙星 14.1%。医院污水的抗生素耐药率均高于所有抗生素，除了两种（氯霉素和庆大霉素）。同样，与未经处理的污水相比，污水处理厂（WWTP）的污水中检测到更高的耐药率。关于多药耐药性，医院污水的发生率最高，城市污水的发生率最低。总的来说，大多数分离株都是潜在的超广谱 -内酰胺酶阳性（ESBL(+))（51.9%），其次是 AmpC(+)（44.4%）和 ESBL(+)/AmpC(+)（35.2%）。在潜在的 ESBL 产生菌中，最常见的基因是 blaOXA（33.3%）、blaTEM（24.1%）和 blaCTX-M（5.6%），而在 AmpC 产生菌中，最常见的基因是 blaEBC（38.9%）、blaFOX（1.9%）和 blaCIT（1.9%）。总之，医院和 WWTP 的活动被认为是该研究区域多药耐药菌传播的主要原因。这些数据对于未来管理这些污染物的环境和公共卫生风险非常重要。这是科英布拉地区首次在水网络中进行抗生素耐药性决定因素的研究。此外，这也是葡萄牙首次同时检测水生系统中 AmpC 和 ESBLs -内酰胺酶多药耐药菌的报告。
