摘要
      广泛应用氯化处理的现场医院废水处理系统被认为是遏制抗生素耐药性传播的重要障碍。氯化残留的有活力和有活力但不可培养的细菌（VBNC）可能会高估消毒效果，而它们从医院污水输入市政管网的抗生素耐药性风险可能会被忽视。在这项研究中，我们量化了现场医院废水处理系统氯化过程中的活/VBNC大肠杆菌和肠球菌，并评估了它们的抗生素耐药性风险。在未经处理的废水中，活的/VBNC大肠杆菌和肠球菌的数量高达5.76–6.34/5.76–6.3 3和5.44–5.76/5.44–5.7 5 log10（细胞/mL）。同时，观察到抗生素耐药性大肠杆菌和肠球菌与可培养大肠杆菌和Enterococcus的比例很高，尤其是携带氨苄青霉素耐药性的大肠杆菌和Enterococcus（22.25–41.70%和28.09–54.05%）。氯化可以去除0.44–1.88‐/0.43–1.88–和0.29–1.29‐/0.28–1.28-log的活菌/VBNC和完全可培养的大肠杆菌和肠球菌，但会导致抗生素抗性基因（ARGs）和可移动遗传元件（MGE）释放到细胞外，并可能进一步增强活菌的抗生素耐药性。抗生素检测率低表明，抗生素耐药性细菌（ARB）的出现可能不会伴随相应的抗生素。不同的采样月份对上述结果有一定影响，而在医院日常工作期间的不同采样时间，结果基本稳定。氯化残留活菌/VBNC大肠杆菌和肠球菌的高释放率（11.26–13.02和11.59–12.98 log10（细胞/h））和累积量（15.41–16.12和15.75–16.14 log10（单元））间接评估了细菌抗生素耐药性进入市政管网的潜在风险。此外，还应认真对待累积量为2.57–4.85、5.73–7.50和5.21–7.14 kg的相应抗生素头孢他啶、环丙沙星和万古霉素的贡献。余氯可以作为风险评估的一个重要信号指标。
Abstract
On-site hospital wastewater treatment system widely applying chlorination has been regarded as an important barrier to curb the dissemination of antibiotic resistance. Chlorination-residual viable and viable but non-culturable (VBNC) bacteria probably lead to overestimate the effect of disinfection, while their antibiotic resistance risks imported from hospital effluents to municipal pipe network may be ignored. In this study, we quantified viable/VBNC Escherichia coli and Enterococcus in chlorination of an on-site hospital wastewater treatment system and assessed their antibiotic resistance risks. The numbers of viable/VBNC Escherichia coli and Enterococcus in raw wastewater were detected as high as 5.76–6.34/5.76–6.33 and 5.44–5.76/5.44–5.75 log10(cells/mL). Meanwhile, high proportions of antibiotic-resistant Escherichia coli and Enterococcus to culturable Escherichia coli and Enterococcus were observed, especially carrying ampicillin resistance (22.25–41.70 % and 28.09–54.05 %). Chlorination could remove 0.44–1.88‐/0.43–1.88- and 0.29–1.29‐/0.28–1.28-log of viable/VBNC and complete culturable Escherichia coli and Enterococcus, but cause antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) to be released outside cells, and possibly further enhance the antibiotic resistance of viable bacteria. Low detections of antibiotics suggested that the occurrence of antibiotic-resistant bacteria (ARB) may not be accompanied by the corresponding antibiotics. Different sampling months had some impacts on above results, while the results were basically stable at different sampling times of hospital daily working period. The high release rates (11.26–13.02 and 11.59–12.98 log10(cells/h)) and cumulative amounts (15.41–16.12 and 15.75–16.14 log10(cells)) of chlorination-residual viable/VBNC Escherichia coli and Enterococcus indirectly assessed the potential risks of bacterial antibiotic resistance entering municipal pipe network. Additionally, the contributions from the corresponding antibiotic ceftazidime, ciprofloxacin, and vancomycin with the cumulative amounts of 2.57–4.85, 5.73–7.50, and 5.21–7.14 kg should also be taken seriously. Residual chlorine could serve as an important signal indicator for the risk assessment.

https://www.sciencedirect.com/science/article/abs/pii/S0048969723007556