摘要

      众所周知，抗生素不仅通过人类排泄物进入环境，还通过牲畜/水产养殖、医疗设施和制药工业废物进入环境。一旦进入环境，抗生素就有能力在微生物群落中提供选择性压力，从而选择耐药性。路易斯安那州东南部的Bayou Lafourche是该地区30万人饮用水的原始水源，此前已被证明受到大量粪便污染。沿河口的四个地点和密西西比河输入源的一个地点进行了为期一年的水化学、总大肠菌群和粪便大肠菌群估计以及抗生素抗性细菌（ARB）和抗生素抗性基因（ARG）的存在监测。对4株废物相关菌株（四环素、磺胺甲恶唑/甲氧苄啶、头孢西丁、美罗培南、亚胺培南、红霉素和万古霉素）进行了抗生素耐药性检测。用PCR/电泳进一步检测耐药菌，以确定是否存在抗生素耐药基因（Sul1、tet（A）、tet（W）、tet（X）、IMP、KPC和OXA-48）。河口似乎符合路易斯安那州环境质量部（LDEQ）的水化学标准，但粪便大肠菌群始终高于LDEQ阈值，因此表明粪便污染。肠杆菌科菌株对四环素、磺胺甲恶唑/甲氧苄啶和头孢西丁的耐药率分别为13.6%、10.9%和19.8%，有11株菌株对tet（A）或Sul1耐药。高粪大肠菌群和ARB/ARG的存在都可能表明存在人为或农业粪便污染源。

       Antibiotics are known to enter the environment, not only by human excretion but also through livestock/aquaculture, healthcare facilities, and pharmaceutical industry waste. Once in the environment, antibiotics have the ability to provide a selective pressure in microbial communities thus selecting for resistance. Bayou Lafourche of Southeastern Louisiana serves as the raw source of drinking water for 300,000 people in the region and has previously been shown to receive high amounts of fecal contamination. Four sites along the bayou and one site from its input source on the Mississippi River were monitored for water chemistry, total and fecal coliform estimates, and presence of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARG) for a period of 1 year. Four waste-associated bacterial isolates were tested for resistance to antibiotics (tetracycline, sulfamethoxazole/trimethoprim, cefoxitin, meropenem, imipenem, erythromycin, and vancomycin). Resistant bacteria were further examined with PCR/electrophoresis to confirm the presence of antibiotic resistance genes (Sul1, tet(A), tet(W), tet(X), IMP, KPC, and OXA-48). The bayou appears to meet the Louisiana Department of Environmental Quality (LDEQ) criteria for water chemistry, yet fecal coliforms were consistently higher than LDEQ thresholds, thus indicating fecal contamination. Enterobacteriaceae isolates showed 13.6%, 10.9%, and 19.8% resistant to tetracycline, sulfamethoxazole/trimethoprim, and cefoxitin, respectively, and 11 isolates were confirmed for presence of either tet(A) or Sul1 resistance genes. High fecal coliforms and presence of ARB/ARG may both indicate a presence of anthropogenic or agricultural source of fecal contamination.

        https://link.springer.com/article/10.1007%2Fs11356-018-4008-5