摘要
对某猪场大肠杆菌Ⅰ型整合子及其基因盒的分子流行病学进行了研究。结果表明:猪场大肠杆菌Ⅰ型整合子流行普遍,192株分离菌中105株携带Ⅰ型整合子,检出率达54.7%。共检出6种Ⅰ型整合子,它们以8种组合形式在猪场大肠杆菌中流行。猪群、饲养员及饲养环境分离菌株Ⅰ型整合子检出种类、检出率相近,但同耐药谱菌株Ⅰ型整合子携带无一致性。各种Ⅰ型整合子整合不同种类、不同数目的耐药基因盒,其中100%整合有氨基糖腺苷转移酶基因(aadA),77%整合有二氢叶酸还原酶基因(dhfr),仅少数整合有链丝菌素乙酰转移酶基因(sat)、β-内酰胺酶基因(bla)及红霉素酯酶基因(ereA)。Ⅰ型整合子携带菌株均表现多重耐药,其中100%耐受复方新诺明,90%耐受链霉素,75%耐受大观霉素。该猪场长期使用磺胺类、氨基糖苷类抗菌药物,尤其是将它们用作抗菌促长剂,造成了携带dhfr及aadA两种基因盒的Ⅰ型整合子在猪场大肠杆菌中广泛流行。
An investigation of class I integron and its gene cassette epidemiology in 192 Escherichia coli strains isolated from a swine farm was carried out by the methods of PCR, sequence, and restriction enzyme analysis. The result showed that one-hundred and five strains (54.7%) of E. coli harbored six types of class I integron in the form of eight combinations. All of E. coli strains from the pigs, the raisers, and the surroundings had similar prevalence of class I integron, but the strains with the same resistant patterns did not always carry the same type of class I integron. Each type of class I integron integrated different kinds and numbers of gene cassette. Among all the detected class I integrons, one-hundred percent carried aminoglycoside adenyltransferase (aadA), seventy-seven percent carried dihydrofolate reductase (dhfr), whereas only a small percentage carried one or two of the beta-lactamase (bla), streptothricin acetyl-transferase (sat), and erythromycin esterase (ereA) genes. All E. coli strains carried class I integrons were multi-resistant, especially resistant to compound sulfamethoxazole ( 100%), streptomycin (90 %), and spectinomycin (75%). High prevalence of class I integrons carrying dhfr and aadA genes had occurred in E. coli strains because sulfonamides and aminoglycosides were used extensively, especially used as antibacterial growth promoter in this swine farm.
出处
《畜牧兽医学报》
CAS
CSCD
北大核心
2005年第9期931-936,共6页
ACTA VETERINARIA ET ZOOTECHNICA SINICA
基金
国家自然科学基金重点项目(31031040)
关键词
大肠杆菌
耐药性
I型整合子
基因盒
Escherichia coli
antimierobial resistance
class I integron
gene cassette