不同补给水源的城市人工湖中异养菌耐药性及耐药菌种属分布研究

Resistance to Antibiotics of Heterotrophic Bacteria from Urban Artificial Lakes with Different Recharge Sources and Their Species Distribution

为了阐明不同补给水源的城市人工湖中异养菌耐药状况和耐药菌种属分布特征,选取分别以地表水和再生水为补水来源的XQ湖和FQ湖为代表进行研究。从2018年4-11月逐月采集水样,考察了各水样中对氨苄西林(AMP)、磺胺甲恶唑(SMZ)和四环素(TET)这3种不同种类抗生素具有耐药性的异养菌含量,并对分离菌株的耐药表型、耐药菌株的种属分布以及水质理化指标进行了分析。结果表明,2处人工湖中的AMP耐药菌和SMZ耐药菌含量约为10^2~10^4CFU·(100 m L)^-1,而TET耐药菌含量则约10^1~10^3CFU·(100 m L)^-1。分离出的84株耐药菌归属于19个种,其中蜡状芽孢杆菌、大肠埃希氏菌、维氏气单胞菌、豚鼠气单胞菌和鸟氨酸拉乌尔菌为2个湖共有耐药菌。71.4%的耐药菌都是对AMP单一耐药,以蜡状芽孢杆菌为主。由于具有固有耐药性的细菌在分离出的耐药菌中占比很低,获得性耐药很可能在城市人工湖中异养菌耐药性的发展上发挥了主要贡献作用。地表水补水的XQ湖和再生水补水的FQ湖在总异养菌含量、耐药菌含量和检出率上均无显著差异。分离来源对16株耐药性气单胞菌的聚类无明显影响。

In order to clarify the antibiotic resistance of heterotrophic bacteria and the distribution characteristics of antibiotic-resistant bacteria in urban artificial lakes supplemented with different water sources,XQ Lake and FQ Lake,which are supplemented with surface water and reclaimed water respectively,were selected as representative urban artifical lakes for research.From April to November 2018,we collected water samples from two lakes each month and investigated the concentration of heterotrophic bacteria resistant to three different antibiotics including ampicillin(AMP),sulfamethoxazole(SMZ)and tetracycline(TET).The antibiotic-resistant phenotype of isolated strains and the species distribution of antibiotic-resistant strains,as well as physical and chemical indicators of water quality were analyzed.The results showed that the concentration of AMP-resistant bacteria and SMZ-resistant bacteria in two artificial lakes was about 10^2~10^4 CFU·(100 m L)^-1,while the concentration of TET-resistant bacteria was about 10^1~10^3 CFU·(100 m L)^-1.The 84 antibiotic-resistant strains isolated belonged to 19 species,among which Bacillus cereus,Escherichia coli,Aeromonas venroii,Aeromonas caviae,Raoultella ornithinolytica were antibiotic-resistant bacteria shared by the two lakes.71.4%of the antibiotic-resistant bacteria are mono-resistant to AMP,mainly Bacillus cereus.Due to very low percentage of bacteria with intrinsic antibiotic resistance in isolated antibiotic-resistant bacteria,it suggested that acquired antibiotic resistance had mainly contributed to the development of antibiotic resistance in heterotrophic bacteria in urban artificial lakes.There was no significant difference in the total heterotrophic bacteria concentration,antibiotic-resistant bacteria concentration and detection rate between the XQ Lake supplemented by surface water and the FQ Lake supplemented by reclaimed water.The source of isolation had no significant effect on the clustering of 16 strains of resistant Aeromonas.