20株奇异变形杆菌耐药基因和整合子分布及亲缘关系分析

Study on distribution of drug resistance gene and integron and analysis of genetic relationship of 20 isolates of Proteus mirabilis

目的了解该院神经内科病区奇异变形杆菌院内感染状况与耐药机制。方法对20株不重复奇异变形杆菌采用PCR法检测超广谱β内酰胺酶（ESBLs）、头孢菌素（AmpC）酶、碳青霉烯酶（KPC）和金属β内酰胺酶（MBLs）耐药基因并测序;PCR法检测整合子并测序;脉冲场凝胶电泳法分析菌株间亲缘关系;对这20株奇异变形杆菌进行药敏试验并分析。结果从这20株奇异变形杆菌中均检测出TEM-1和CTX-M-14型耐药基因,10株菌中分离出CMY-2型耐药基因。从19株菌中扩增出Ⅰ类整合子,分别整合的基因盒有＂aacA4＋cmlA1＂,＂dfrA12＋orfF＋aadA2＂和＂dfrA32＋ereA＋aadA2＂。脉冲场凝胶电泳结果聚类分析20株菌可分为P1～P11的11个PFGE型别,其中P1～P3的12株菌为同一克隆株。20株菌对美罗培南、阿米卡星、氨曲南、头孢他啶和哌拉西林/他唑巴坦的敏感率高。结论该院神经内科病区出现奇异变形杆菌同克隆株的传播;携带的耐药基因以CTX-M-14和CMY-2型为主;Ⅰ类整合子携带率高,耐药基因盒以＂aacA4＋cmlA1＂和＂dfrA12＋orfF＋aadA2＂为主;菌株对美罗培南、阿米卡星和氨曲南均为敏感;临床科室应同样重视由奇异变形杆菌引起的院内感染,加强感染控制措施。

Objective To investigate the prevalence and resistance mechanisms of Proteus mirabilis in the ward of neurology de‐partment of our hospital .Methods For a total of 20 clinic isolates of Proteus mirabilis ,PCR were used for the detection of AmpC , ESBLs ,KPC and MBLs and then DNA sequencing was performed .The integrons were also detected by using PCR and then sequen‐cing was carried out .The genetic relationship between isolates were detected and analysed by pulsed‐field gel electrophoresis（PF‐GE） .The results of drug sensitivity tests were analysed .Results TEM‐1 and CTX‐M‐14 gene were found in all the 20 isolates ,the 10 isolates of Proteus mirabilis were also found carrying CMY‐2 gene .Class Ⅰ integrons were amplified from 19 strains carrying gene cassettes ＂aacA4＋cmlA1＂,＂dfrA12＋orfF＋aadA2＂and ＂dfrA32＋ereA＋aadA2＂ respectively .PFGE analysis revealed that the 20 isolates were grouped into 11 PFGE types P1-P11 ,the 12 isolates of P1-P3 were same clones .The sensitive rates of the i‐solates to Meropenem ,Amikacin ,Aztreonam ,Ceftazidime and Tazocin were high .Conclusion Nosocomial transmission of the same clone of Proteus mirabilis was appeared in the ward of neurology department of our hospital .The predominance drug‐resistance genes were CTX‐M‐14 andCMY‐2 .The incidence of carrying class Ⅰ integrons was high ,and the major gene cassettes were＂aacA4＋cmlA1＂and ＂dfrA12＋orfF＋aadA2＂.The 20 isolates were all sensitive to Meropenem ,Amikacin and Aztreonam .Other Clinical departments should also pay attention to the nosocomial infection caused by Proteus mirabilis and strengthen the infection control measures .