Mai Xiao-bei, Tao Ran, Yang Yang, Zhang Min, Lin Jian-hua, Man Ying
Huan Jing Ke Xue. 2015 May;36(5):1776-84.
Environmental indigenous bacteria (Staphylococcus and Pseudomonas) were isolated from 9 different constructed wetlands (CWs) in summer and winter. The antibiotic resistance analysis of the isolated bacteria was conducted by Kirby-Bauer disc agar diffusion method. And the quantitative PCR assay was used to quantify the abundance of class I integron (int1) in the matrix of CWs. The results indicated that over 84% of isolates among the 522 Staphylococcus strains and 543 Pseudomonas strains had antibiotic resistance and above 68% of isolates had multi-antibiotic resistance, the average of MRI index was 0.22. Antibiotic resistance of indigenous bacteria in CWs was at the same resistance level of human or animal bacteria in certain environment, indicating that indigenous bacteria from constructed wetlands had relatively high level of resistance. Staphylococcus and Pseudomonas strains had higher resistances to Ampicillin (AMP) and Sulfamethoxazole (SXT), and extremely low resistance rates of lower than 3% to Tetracycline (TE), Gentamicin (CN) and Ciprofloxacin (CIP). To Ceftazidime (CAZ) and Chloramphenicol (C), the two kinds of indigenous bacteria showed distinctly different resistances. Quantitative PCR revealed that the abundance of intl in CWs was 1.14 x 10(5)-5.66 x 10(5) copies · g(-1), and its relative abundance was 0.54%-3.68%. Both of season and wetland type had important impact on antibiotic resistance and abundance of int1. The antibiotic resistance rate and the multiple resistance index (MRI) for the indigenous bacteria and the abundance of int1 in summer were higher than those in winter. Among three types of CWs, the antibiotic resistance rate and the MRI value were the highest in the downward vertical flow, while the int1 abundance was the highest in the sub-surface flow. The research indicated that indigenous bacteria acquired antibiotic resistance due to long term exposure to antibiotics of certain concentrations and antibiotic-resistant intestinal bacteria in sewage environment. The environmental risks of antibiotic resistant bacteria and resistant genes in CWs should not be ignored.
在夏季和冬季，从9个不同的人工湿地（CWs）中分离出环境土著细菌（葡萄球菌和假单胞菌）。采用 Kirby-Bauer 纸片琼脂扩散法对分离出的细菌进行抗生素耐药性分析。并使用定量PCR测定法对人工湿地基质中I类整合子（int1）的丰度进行定量。结果表明，在522株葡萄球菌菌株和543株假单胞菌菌株中，超过84%的分离株具有抗生素耐药性，超过68%的分离株具有多重抗生素耐药性，平均多重耐药指数（MRI）为0.22。人工湿地中土著细菌的抗生素耐药性与特定环境中人类或动物细菌的耐药水平相当，表明人工湿地中的土著细菌具有较高的耐药水平。葡萄球菌和假单胞菌菌株对氨苄青霉素（AMP）和磺胺甲恶唑（SXT）具有较高的耐药性，对四环素（TE）、庆大霉素（CN）和环丙沙星（CIP）的耐药率极低，低于3%。对于头孢他啶（CAZ）和氯霉素（C），这两种土著细菌表现出明显不同的耐药性。定量PCR显示，人工湿地中intl的丰度为1.14×10（5）-5.66×10（5）拷贝·克（-1），其相对丰度为0.54%-3.68%。季节和湿地类型对抗生素耐药性和int1的丰度都有重要影响。夏季土著细菌的抗生素耐药率和多重耐药指数（MRI）以及int1的丰度均高于冬季。在三种类型的人工湿地中，下行垂直流的抗生素耐药率和MRI值最高，而潜流中int1的丰度最高。研究表明，土著细菌由于长期暴露于污水环境中一定浓度的抗生素和耐抗生素肠道细菌而获得了抗生素耐药性。人工湿地中抗生素耐药细菌和耐药基因的环境风险不容忽视。
