城市污水处理厂所出水中的细菌对抗生素耐性的研究

Antibiotic Resistance of Bacteria in Effluents of Municipal Wastewater Treatment Plants

为研究城市污水厂所出水中的一般细菌对抗生素的耐性。在成都市选取了2座有代表性的污水厂,检测分析其出水中的细菌分别对6种抗生素(青霉素、头孢氨苄、环丙沙星、四环素、庆大霉素、阿奇霉素)的抗性菌浓度、比例、及半抑制浓度。结果表明:2座污水厂出水的细菌总数随着抗生素浓度的增加而减少;青霉素和头孢氨苄对细菌总数的影响较小,四环素和环丙沙星对细菌总数的影响较大。青霉素的抗性菌浓度最高,A、B厂分别高达6.5×104、2×104CFU/mL,B厂的四环素抗性菌浓度最低为8.9×102CFU/mL。A、B污水厂出水中细菌的庆大霉素抗性水平最高,其半抑制浓度分别高达28.1mg/L和25.4mg/L。2座污水厂出水细菌的抗生素半抑制浓度高于污水中的抗生素浓度,低浓度的抗生素是抗性菌稳定存在的重要因素,因此应该谨慎抗生素的使用,降低抗性菌的环境污染风险。

Prevalence of antibiotic-resistant bacteria in wastewater effluents was concerned as an emerging contaminant. To estimate antibiotic resistance of bacteria in effluents of municipal wastewater treatment plants （WWTP）, antibiotic tolerance, proportion of antibiotic-resistant bacteria, and hemi-inhibitory concentrations of six antibiotics （Penicillin, Cefalexin, Ciprotloxacin, Tetracycline, Gentamiein and Azithromycin） were determined at two wastewater treatment plants in Chengdu. The results showed that the total bacterial counts decreased along with the increase of antibiotic concentration, and the variations of Penicillin and Cefalexin were relatively higher than that of Tetracycline and Ciprotloxaein. Moreover, the concentrations of Ampieillin-resistant bacteria were highest to 6.5 × 10^4 and 7.2×10^4 CFU/mL in WWTP-A and WWTP-B, respectively, and the lowest antibiotic-resistant bacteria concentration was also as high as 8.9 CFU/mL. The hemi-inhibitory concentration of Gentamiein was highest in the 6 antibiotics, they were high to 28.1 mg/L and 25.4 mg/L in the two wastewater treatment plants. The data also indicated that the hemi-inhibitory concentrations of the bacteria to 6 antibiotics were much higher than common concentrations of antibiotics in sewages, which suggested that antibiotic-resistant bacteria could exist over a long period in the effluents with low concentrations of antibiotics. Antibiotic-resistant bacteria could be a potential microbial risk during sewage effluent reuse or emission into environmental waters.