摘要
目的研究整合子在医院感染阴沟肠杆菌中的分布及其与细菌耐药的相关性,探讨Ⅰ类整合子与临床耐药播散的关系。方法运用K-B法检测临床株的耐药表型,双纸片扩散法检测ESBLs,PCR扩增筛选含整合子的临床菌株,接合传递实验、套式PCR、质粒谱分析及DNA测序研究携带耐药基因的Ⅰ类整合子与耐药播散的关系。结果医院感染阴沟肠杆菌69.2%含Ⅰ类整合子,未检测出Ⅱ类和Ⅲ类整合子。Ⅰ类整合子可变区扩增片段大小从1.0～2.3kb不等,编码对氨基糖苷类抗生素、磺胺类药物和氯霉素耐药的基因。整合子阳性组中ESBLs、多重耐药菌均明显高于阴性组。整合子可通过质粒在不同菌属间水平传播。结论Ⅰ类整合子在医院感染阴沟肠杆菌中广泛分布,可通过质粒在不同菌属间水平传播,在耐药基因传播中起重要作用,应引起临床足够的重视。
Objectives Thirty nine unrelated clinical strains of Enterobacter cloacae collected from inpatients of the First Affiliated Hospital of Wenzhou Medical College. Methods Drug resistance test was performed by KB method. ESBL-positive strains were detected by double-disk synergy test. Integron was determined by PCR assay with integron-specific-primer. Conjugative transfer test, plasmid profile analysis, nested-PCR, and DNA sequence analysis were used to research for resistant horizontal transferable mechanism of integron mediated. Results Class Ⅰ integrons were detected in 27 of 39 （69. 2% ） unrelated clinical strains of E. cloacae from inpatients in Wenzhou. The presence of integrons was significantly correlated with simultaneous resistance to several antibiotics. Class Ⅰ integrons harbored four different gene cassette arrays. The size of amplicons was from 1,000 to 2, 300bp. Gene cassettes included genes encoding resistance to aminoglycosides （aadA1, aacIA2, aadA5, aacA4）, trimethoprim-sulfamethoxazole （ dfrA12, dfrA17）, and chloramphenicol （catB8）. Strains positive for class I integron were highly related to muhidrug resistance and ESBLs. Class Ⅰ integron could horizontal transfer along with plasmid among bacteria. Conclusions Our results generally demonstrated the wide distribution of integron structures in E. cloacae isolates within the hospital environment throughout Wenzhou, China. Drug resistance were more liable to horizontal transfer via class Ⅰ integron along with plasmid. It implied the necessary for surveillance horizontal transference of antibiotic resistance gene among bacteria genus.
出处
《中国抗生素杂志》
CAS
CSCD
北大核心
2009年第4期254-256,I0001,I0002,共5页
Chinese Journal of Antibiotics
关键词
阴沟肠杆菌
整合子
水平播散
Enterobacter cloacae
Integron
Horizontal transfer
