摘要
目的研究南京地区鲍曼不动杆菌中整合子的流行现状、与耐药的相关性及携带的耐药基因。方法收集106株南京地区鲍曼不动杆菌,纸片扩散法测定其药敏情况;PCR-限制性片段长度多态性(RFLP)筛查整合子并分类;PCR法扩增整合子可变区;联合RFLP和DNA测序技术分析整合子携带的耐药基因。结果52.8%(56/106)鲍曼不动杆菌检出整合子,PCR—RFLP结果显示均为Ⅰ类整合子;94.6%(53/56)整合子阳性菌株可变区扩增阳性,扩增片段大小为0.15～2.8kb;共检出7种不同的可变区,含有编码对氨基糖苷类抗生素(aadA1、aadA2、aadA5、aadB、aacA4)、磺胺类抗菌药(dfrⅫ、dfr17)、β内酰胺类抗生素(bla_(axa-10))和氯霉素(catB-like、catB8)耐药的基因及2个功能不清的开放阅读框(orfF、orfI);发现1例新型基因盒组合形式orfI—aadA1,GenBank基因号为DQ092497。结论Ⅰ类整合子广泛存在于南京地区鲍曼不动杆菌中;整合子与鲍曼不动杆菌的耐药和多重耐药有关;鲍曼不动杆菌整合子主要携带氨基糖苷类耐药基因。
Objective To investigate the prevalence of integrons in A. baumannii isolates, analyze the correlation between integrons and resistance of A. baurnannii, and study the resistance genes in integrons. Methods A total of 106 strains of A. baumannii were collected to test the antibiotic susceptibility by disk diffusion method. The classification of integrons was performed by analyzing the positive PCR products using restriction fragment length polymorphism （RFLP）. The variable region of integrons was amplified by integron PCR. RFLP and DNA sequencing were used to analyze the resistance genes in integrons. Results About 52.8% （56/106） of the isolates showed integron positive. PCR-RFLP analysis revealed that they were all class I integrons. About 94.6% （53/56） of the positive strains with integrons owned the variable region, which was confirmed by integron PCR. The sizes of the amplicons ranged from 0.15 kb to 2.8 kb. All together 7 different cassette arrays were detected, including genes coding resistance to aminoglycosides （aadA1, aadA2, aadA5, aadB, aacA4）, sulphonamides （dfrⅫ, d fr17） , β-1actam compounds （blaaxa-10） , ehloramphenicol （catB-like, catB8） , and two open reading frames （orfF, orfI） with unknown function. A novel cassette array orfl-aadA1 was reported, and its GenBank accession number was DQ092497. Conclusions Class I integrons are widespread in A. baurnannii isolates in Nanjing. The integrons are closely associated with the resistance and multidrug resistance in A. baurnannii isolates.
出处
《中国感染与化疗杂志》
CAS
2007年第5期339-343,共5页
Chinese Journal of Infection and Chemotherapy
关键词
整合子
耐药
基因盒
鲍曼不动杆菌
Integron
Resistance
Gene cassette
Acinetobacterbaumannii
