Isolation and Identification of Bacteria in the Activated Sludge from Four Sewage Treatment Plants in Nanjing City and Its Antibiotic Resistance Analysis
南京市4个污水处理厂的活性污泥中细菌的分离鉴定和抗生素耐药性分析

Bacteria were isolated from the activated sludge of CN, CE, JN and JM Sewage Treatment Plants (STPs) in Nanjing city and identified by 16S rDNA sequence analysis. The antibiotic resistance analysis of the isolated bacteria was conducted by Kirby-Bauer Disc Agar Diffusion Method. The objective of this study is to clarify the current state of bacteria antibiotic resistance from the four STPs and analyze the potential environmental risk of the produced waste water and the sludge. The 7, 9, 8 and 11 bacterial strains with different morphology were respectively isolated from the above four sample sites, which belonged to 25 species and 17 genera. Antibiotic resistance analysis indicated that 97.1% of isolates had antibiotic resistance and 80% of isolates had multi-antibiotic resistance. The drug resistance rates were 71.4%, 37.1%, 37.1%, 57.1%, 34.3%, 68.6%, 94.3% and 65.7% of ampicillin(AM), kanamycin(KAN), chloromycetin(CHL), streptomycin(STR), gentamicin(GEN), tetracycline(TET), erythromycin(EM) and spectinomycin(SPE), respectively. It indicated that the activated sludge from the four STPs had high antibiotic resistance. The drug resistance analysis between different bacteria indicated that the genus Aeromonas, an aquacultural pathogen, had multi-antibiotic resistance, while all of Bacillus were sensitive to CHL, STR and GEN. The STPs should enhance the sterilization of effluent water to avoid the second pollutions.