泰安渿河中产ESBLs大肠杆菌耐药性及耐药基因的传递规律

Antibiotic resistance and antibiotic resistance gene transfer of ESBLs-producing Escherichia coli in Naihe, Taian

【目的】调查城市河流泰安市渿河(贯穿城区)中产超广谱β-内酰胺酶(extended-spectrumβ-lactamases,ESBLs)大肠杆菌的分布及其多重耐药性与耐药基因携带情况,探究其耐药基因传递规律。【方法】采用Kirby-Bauer法测定耐药表型,用PCR和基因序列测定法进行耐药基因、整合子检测和多位点序列分型,并进行细菌接合试验。【结果】从272份水样中分离88株产ESBLs大肠杆菌,分离率32.4%,多重耐药率为59.1%。耐药基因检测出blaTEM、qnrS、AacC2、aac(6’)-Ib-cr、oqxA、OXA、AacC4,携带率分别为94.3%、33.0%、29.5%、12.5%、11.4%、6.8%、5.6%,59.0%菌株携带多种耐药基因。MLST分型检测出47种ST型,ST38为主要分型占13.6%,发现ST131两株。I类整合子检出率26.1%,其中,dfrA17-aadA5阳性率为13.6%。接合率为83.0%(73/88),72.6%的接合子发生耐药谱变窄,供体菌所携带的七种耐药基因均发生了水平传递。【结论】城市河流中细菌多重耐药现象严重且耐药性可水平传递,存在城市公共卫生安全隐患。

[Objective]To study the distribution of extended-spectrumβ-lactamase-producing Escherichia coli in Naihe,Taian City,as well as its multiple antibiotic resistance and relative antibiotic resistance genes,and further reveal the mechanism of antibiotic resistance gene transmission.[Methods]We used Kirby-Bauer method to determine the antibiotic resistance profiles,PCR for the detection of antibiotic resistance genes and Class I integrons,and multilocus sequence typing among ESBLs-producing Escherichia coli strains,and conducted the bacterial conjugation test.[Results]We isolated 88 ESBLs-producing Escherichia coli strains out of 272 water samples with the detection rate of 32.4%and the multiple antibiotic resistance rate of 59.1%.Resistance genes including blaTEM,qnrS,AacC2,aac(6’)-Ib-cr,oqxA,OXA and AacC4 were detected with the detection rates of 94.3%,33.0%,29.5%,12.5%,11.4%,6.8%and 5.6%respectively.59%of strains carried multiple drug resistance genes.We observed 47 sequence types(STs)in 88 isolates,and 13.6%of them were ST38;we also detected two ST131 strains.The positive rate of Class I integrons was 26.1%,and the predominate gene cassette was dfrA17-aadA5 with detection rate of 13.6%.The conjugation rate was 83.0%(73/88),72.6%of the conjugates turned into narrower antibiotic resistance profiles.We observed horizontal transfer in all seven antibiotic resistance genes carried by the donor bacteria.[Conclusion]The bacterial multiple antibiotic resistance existed in urban rivers and the resistance genes were capable to transfer horizontally,which could be potential hazard that threatened public health.