白颈长尾雉圈养种群大肠杆菌耐药性及其耐药基因

Antibiotic-resistance and Antibiotic-resistant Gene of Escherichia coli Isolated from Syrnaticus ellioti in Captivity

对白颈长尾雉圈养条件下的38个样品进行大肠杆菌分离及PCR检定,并采用肠杆菌基因间重复共有序列PCR指纹法(ERIC)剔除各个样品的重叠分离株,检测获得的170个大肠杆菌分离株对9种抗生素的耐药性、Ⅰ型整合子携带率及其可变区抗性基因,结果显示:(1)来自白颈长尾雉的分离株对实验用的9种抗生素的抗性比率和多重耐药性远高于环境源和人源者(来自白颈长尾雉的分离株100%耐受3种及以下的抗生素,而环境源者为50.7%,人源者66.7%);(2)来自白颈长尾雉的分离株的Ⅰ型整合子携带率(92%)高于环境源(87%)和人源(78%);(3)来自白颈长尾雉和来自人的大肠杆菌分离株的Ⅰ型整合子可变区抗生素抗性基因检出率相同(36%),但高于环境源(24%);(4)携带Ⅰ型整合子的分离株对实验用的抗生素的抗性百分率一般高于不携带者,只有个别种类抗生素这种差异为非显著性差异;(5)Ⅰ型整合子可变区基因盒的基因为3类,即aadA、dfrA和未知功能的orfF;aadA、dfrA的频率相同;3类基因均以基因盒形式存在,分别是dfrA17-aadA5、dfrA12-ofrF-aadA2、dfrA12-aadA2。

170 of Escherichia coli isolated from 38 samples were collected from Syrnaticus ellioti in captivity and PCR test, and the enterobacter repeated intergenic consensus sequence PCR fingerprinting（ERIC） to eliminate the overlapping separation of isolates, which were tested of their resistance against 9 antibiotics, the occurrence of class 1 integrons and genetic elements involved multi-resistance. In this study, results show that,（1） isolates from Syrnaticus ellioti exhibited higher resistance ratio and more multiple resistance to the antibiotics than those from artificial breeding and natural breeding（for example, 100% isolates from Syrnaticus ellioti resisted to 1 or 2 antibiotics, but those from artificial breeding and natural breeding were only 66.7% and 50.7%, respectively）;（2） the occurrence of class Ⅰ integrons in isolates from Syrnaticus ellioti（92%） was higher than those from the natural breeding（87%） and artificial breeding（78%）;（3） positive ratio of genetic elements involved multi-resistance was 36%in the isolates from Syrnaticus ellioti and artificial breeding but 24% was in the isolates form the natural breeding;（4） isolates with positive test of class Ⅰ integrons showed higher resistance ratio to the antibiotics in study than those with negative test;（5） Three classes of gene were discovered in the resistance gene cassettes in variable region of classⅠ integrons, namely aadA, dfrA and orfF with unknown function; the three classes of gene all existed in the following gene cassettes： dfrA17-aadA5 or dfrA12-ofrF-aadA2 or dfrA12-aadA2.