广东省水禽源大肠杆菌Ⅰ型整合子的检测分析

Investigation on classⅠintegrons gene cassettes of Escherichia coli from waterfowl in Guangdong province

为了解广东省水禽源大肠杆菌中Ⅰ型整合子基因盒流行情况,本试验对251株广东地区水禽源大肠杆菌的Ⅰ型整合子进行了检测分析。采用PCR方法扩增Ⅰ型整合酶基因和Ⅰ型整合子基因盒,经限制性内切酶酶切和测序鉴定基因盒插入区。结果显示:98%水禽大肠杆菌检测到Ⅰ型整合酶基因,但只有67.7%大肠杆菌扩增出Ⅰ型整合子基因盒。携带Ⅰ型整合子的大肠杆菌共扩增出8类(A、B、C、D、E、F、G和H)不同的基因盒插入区,其中C类(插入基因为dfrA1-aadA1)检出率最高,高达57.1%(97/170),而A类和H类检出率最低,仅1.15%(2/170)。52株大肠杆菌扩增出2个基因盒,2株大肠杆菌扩增出3个基因盒,分别占携带Ⅰ型整合子大肠杆菌的30.6%和1.15%。结果表明:大肠杆菌Ⅰ型整合子插入的耐药基因盒较多,结构较复杂,促进细菌多重耐药菌株的进化。

For further understanding the circulate information of the classⅠintegrons gene cassettes of Escherichia coli（E.coli）from waterfowl in Guangdong province,in this study,such kind of integrons genes of251 E.coli from waterfowl were detected and analyzed.Polymerase chain reaction（PCR）were employed for the amplifications of the classⅠintegrase gene and the classⅠintegrons gene cassettes.Afterward,the insert regions of integrons gene cassettes were verified by restriction enzyme digestion and gene sequence.From this study,98% E.coli from waterfowl were showing positive on the classⅠintegrase gene,while only67.7%of which were showing positive on the classⅠintegrons gene cassettes.8different types（A,B,C,D,E,F,G and H）of integrons gene cassettes insert regions were verified in the E.coli strains carrying the classⅠintegrons gene,among which,C type（insert gene：dfrA1-aadA1）insert region had the highest positive rate（57.1%,97/170）,while A and H type were known to have the lowest positive rate（1.15%,2/170）.Each of 52 strains was found carrying 2gene cassettes（30.6%,52/170）,while each of 2strains was carrying 3（1.15%,2/170）.The result above indicated that,a high amount of resistenc gene cassettes with complex structure were carried by the classⅠintegrons gene of E.colifrom waterfowl in Guangdong province.The evolution of multi-drug strains may be promoted under this condition.