紫外线消毒后耐药性大肠埃希氏菌的光复活特性

为了考察耐药性大肠埃希氏菌在紫外线消毒后的光复活特性及耐药性的变化，选用从城市污水处理厂分离得到的多重耐药性大肠埃希氏菌SER8作为受试菌株进行紫外线消毒和光复活研究。考察不同剂量紫外线辐照对大肠埃希氏菌SER8的光复活率和光复活速率的影响，以及在磷酸盐缓冲溶液和二沉池出水中复活情况的差别。采用Kirby-Bauer纸片琼脂扩散法考察在紫外线消毒和光复活过程中大肠埃希氏菌SER8对四环素、氨苄西林、诺氟沙星、链霉素、庆大霉素、头孢噻肟、磺胺甲恶唑、环丙沙星和氯霉素的耐药表型。结果表明，在10~40 mJ·cm-2紫外线辐照剂量范围内，大肠埃希氏菌SER8的光复活率和光复活速率基本上随着紫外线辐照剂量的增大而减小。在紫外线消毒后接受日光灯照射的48 h内，大肠埃希氏菌SER8在二沉池出水中的复活率基本与磷酸盐缓冲溶液中的相似，但在48~72 h阶段存在一定的差异。接受20 mJ·cm-2紫外线辐照后经日光灯照射48 h的过程中，大肠埃希氏菌SER8对9种抗生素的耐药表型均未发生变化。

Photoreactivation characteristics of antibiotic-resistant Escherichia coli after ultraviolet disinfection

In order to investigate changes in the photoreactivation and resistance of Escherichia coli after ultraviolet disinfection, multidrug-resistant Escherichia coli SER8, isolated from a municipal wastewater treatment plant, was chosen as the target strain for this study. The effects of different doses of ultraviolet radiation on the rate and speed of Escherichia coli SER8 photoreactivation and photoreactivation in phosphate buffer and secondary effluent were investigated. Using the Kirby-Bauer disk diffusion method, the resistance phenotype of Escherichia coli SER8 to tetracycline, ampicillin, norfloxacin, streptomycin, gentamicin, cefotaxime, sulfamethoxazole, ciprofloxacin, and chloramphenicol during ultraviolet disinfection and photoreactivation was analyzed. The results revealed that the rate and speed of photoreactivation decreased with increasing doses of ultraviolet radiation (from 10 mJ·cm-2 to 40 mJ·cm-2). While the photoreactivation rate in the secondary effluent was similar to that in the phosphate buffer under 48 h of irradiation by a sunlight lamp, following ultraviolet disinfection, some differences were observed between 48 and 72 h. The resistance phenotype of Escherichia coli SER8 to nine antibiotics remained unchanged during the 48 h of irradiation by a sunlight lamp, following 20 mJ·cm-2 of ultraviolet irradiation.