The World Health Organization (WHO) recently classified Enterobacteriaceae resistance to third-generation cephalosporin into the group of pathogens with critical criteria for future research. A study to assess the antibiogram and beta-lactamase genes among the cefotaxime resistant E. coli (CREc) from a South African wastewater treatment plant (WWTP) was conducted using standard phenotypic and molecular biology characterization methods. Approximate total E. coli (TEc) concentration (log10 CFU/mL) ranged between 5.7 and 6.8 among which cefotaxime resistant E. coli were between 1.8 and 4.8 (log10 CFU/mL) for cefotaxime antibiotic concentration of 4 and 8 mg/L in the influent samples. Effluent samples, heavily influenced by the chlorination had only 0.3 log10 CFU/mL of TEc. Fifty-one cefotaxime resistant isolates were selected out of an overall of 75 isolates, and subjected to a new round of testing, with a follow up of 36 and 48 isolates for both colistin and gentamicin, respectively as guided by initial results. Selected CREc exhibited resistance to amoxicillin-clavulanic acid (35.3%; n = 51), colistin sulphate (76.5%; n = 36), ciprofloxacin (47.1%; n = 51), gentamicin (87.5%; n = 48) and intermediate-resistance to meropenem (11.8%; n = 51). Extended spectrum-beta-lactamase genes detected, viz.: blaCTX-M (52.6%; n = 38) and blaTEM (84.2%; n = 38) and concurrent blaCTX-M + blaTEM (36.8%; n = 38), but no blaSHV was detected. Carbapenem resistance genes, blaKPC-2 (15.8%; n = 38), blaOXA-1 (57.9%; n = 38), blaNDM-1 (15.8%; n = 38) were also detected. Approximately, 10.5 - 36.8% (n = 38) co-occurrence of two or more beta-lactamase genes was detected in some isolates. Out of the selected number (n = 30), 7(23.3%) were enterotoxigenic E. coli (ETEC), 14 (46.7%) were Enteroaggregative E. coli (EAEC), but no enteropathogenic E. coli (EPEC) was detected. Resistance to cefotaxime and the presence of a wide range of beta-lactamase genes exposed the potential risks associated with these pathogens via occupational and domestic exposure during the reuse of treated wastewater.

中文翻译：

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废水处理厂中对头孢噻肟耐药的大肠杆菌中的抗菌素和β-内酰胺酶基因。

世界卫生组织（WHO）最近将肠杆菌科细菌对第三代头孢菌素的耐药性归类为病原体，并提出了未来研究的关键标准。使用标准表型和分子生物学表征方法，进行了一项评估来自南非废水处理厂（WWTP）的头孢噻肟抗性大肠杆菌（CREc）中的抗菌素和β-内酰胺酶基因的研究。大肠杆菌中的头孢噻肟抗生素浓度为4至8 mg / L时，大约总大肠杆菌（TEc）浓度（log10 CFU / mL）在5.7至6.8之间，其中对头孢噻肟耐药的大肠杆菌在1.8至4.8（log10 CFU / mL）之间。进水样品。受氯化作用严重影响的废水样品的TEc只有0.3 log10 CFU / mL。从总共75种分离物中选择了51种对头孢噻肟耐药的分离株，并进行了新一轮的测试，随后按照初步结果对大肠菌素和庆大霉素分别分离了36种和48种分离株。选定的CREc表现出对阿莫西林-克拉维酸（35.3％; n = 51），硫酸粘菌素（76.5％; n = 36），环丙沙星（47.1％; n = 51），庆大霉素（87.5％; n = 48）和中间药物具有耐药性-对美罗培南的耐药性（11.8％; n = 51）。检测到超广谱β-内酰胺酶基因，即blaCTX-M（52.6％; n = 38）和blaTEM（84.2％; n = 38）和同时出现的blaCTX-M + blaTEM（36.8％; n = 38），但未检测到blaSHV。还检测到碳青霉烯抗性基因blaKPC-2（15.8％; n = 38），blaOXA-1（57.9％; n = 38），blaNDM-1（15.8％; n = 38）。大约10.5-36。在某些分离物中检测到8％（n = 38）同时存在两个或多个β-内酰胺酶基因。在所选择的数量（n = 30）中，有7（23.3％）是产肠毒素的大肠杆菌（ETEC），有14（46.7％）是肠聚集性大肠杆菌（EAEC），但未检测到肠致病性大肠杆菌（EPEC） 。对头孢噻肟的抗药性和广泛的β-内酰胺酶基因的存在，通过在处理后的废水回用期间的职业和家庭接触，暴露了与这些病原体相关的潜在风险。