携带新型耐药基因盒组合形式Ⅰ类整合子的铜绿假单胞菌耐药特性分析

Features of antibiotic resistance in the Pseudomonas aeruginosa strains with a class Ⅰ integron carrying new array of gene cassettes

目的分析1株临床分离携有多重耐药基因盒整合子的铜绿假单胞菌的耐药特性。方法应用PCR-限制性片段长度多态性(PCR-RFLP)对整合子进行检测及分型,用长片段PCR(Long-PCR)扩增整合子的可变区并进行DNA测序,分析整合子可变区含有的耐药基因。同时应用PCR扩增金属酶基因和oprD2基因。结果该株铜绿假单胞菌PA27携带Ⅰ类整合子,其可变区大小为3.0kb,含有编码对氨基糖苷类、氯霉素和β内酰胺类抗生素耐药的基因,经与GenBank数据库进行同源性分析(BLAST),确定为一种新型基因盒组合形式:aac(6′)-Ⅱ-cmlA8-OXA-10,GenBank登录号为EU708817。oprD2基因检测阳性,未检出IMP-1、VIM-2和IMP-2型金属酶基因。结论该地区首次报道携带新型基因盒组合形式的Ⅰ类整合子的铜绿假单胞菌,并携有多重耐药基因,应引起临床高度重视。

Objective To analyze the characteristics of antibiotic resistance in the P. aeruginosa strains with a class Ⅰ integron carrying new array of gene cassettes. Methods PCR RFLP method was used to detect and type the integron. Long-PCR was used to amplify the variable region of the integron. DNA sequencing analysis was finally applied to confirm the antibiotic resist ance gene. Metallo-beta-lactamase gene and oprD2 gene were amplified by PCR. Results P. aeruginosa PA27 has a class Ⅰ in tegron which has a 3.0 kb length variable region, containing gene cassettes resistant to aminoglycosides, ehloramphenicol and lactam antibiotics. A new array of gene cassettes in the integron： aac（6＇）-Ⅱ-cmlA8-OXA-10 was confirmed by comparing with GenBank database by BLAST. EU708817 is the GenBank accession number. Meanwhile PA27 was positive for oprD2 gene, negative for IMP-1 ,VIM-2 and IMP-2 MBL by PCR. Conclusions A class Ⅰ integron carrying new array of gene cassettes was identified in our region for the first time. This structure carries muhi-antibiotic resistance genes should be paid close attention in the clinic.