耐亚胺培南铜绿假单胞菌耐药特征及其耐药机制的研究

A study of the characteristics of imipenem-resistant Pseudomonas aeruginosa and the mechanisms of its resistance

目的探讨耐亚胺培南铜绿假单胞菌耐药特征及其耐药机制。方法选取2013年12月-2015年8月本院临床送检标本分离的40株耐亚胺培南铜绿假单胞菌,采用全自动微生物分析仪对其进行细菌鉴定,并采用纸片扩散法对其进行药敏试验,聚合酶链反应（PCR）检测碳青霉烯酶相关基因（IMP、VIM、OXA、GES）及外膜蛋白基因oprD,分析其耐药特征以及耐药机制。结果耐亚胺培南铜绿假单胞菌对阿米卡星的耐药率最低,为8.26%;对庆大霉素、妥布霉素的耐药率在20%以下;对环丙沙星、左氧氟沙星、哌拉西林、他唑巴坦、舒巴坦的耐药率在40%~60%之间;对头孢他啶、头孢曲松、头孢吡肟、氨曲南、美罗培南、复方磺胺甲噁唑、米诺环素等抗菌药物的抗菌活性较差,耐药率均在60%以上;而对氨苄西林全部耐药。40株耐亚胺培南铜绿假单胞菌中检测出1株OXA-17阳性菌株,阳性率为2.50%;检测出oprD2基因缺失菌株13株,缺失率为32.50%;未检测出IMP、VIM以及GES等其他耐药基因。结论临床上应该重视和加强对细菌耐药性的监测,合理地应用低耐药的抗菌药物,以减少耐药菌株的产生。

Objective To examine the characteristics of imipenem-resistant Pseudomonas aeruginosa and its mechanisms of drug resistance. Methods Forty strains of imipenem-resistant P.aeruginosa were isolated from clinical specimens that were tested at this Hospital from December 2013 to August 2015.An automated microorganism analyzer was used to identify bacteria and a drug sensitivity test was performed using the disc diffusion method.A polymerase chain reaction（PCR）was performed to detect carbapenemase genes（IMP,VIM,oxa,and GES）and the outer membrane porin OPRD gene,and the characteristics of resistance and the mechanisms of resistance were analyzed. Results Imipenem-resistant P.aeruginosa had the lowest resistance to amikacin（8.26%）.Its resistance to gentamicin and tobramycin was below20% and its resistance to ciprofloxacin,levofloxacin,piperacillin,piperacillin,tazobactam,and sulbactam was 40% ~60%.Antibacterials such as ceftriaxone ceftazidime,ceftriaxone,cefotaxime cefepime,aztreonam,meropenem,trimethoprim sulfamethoxazole,and minocycline were less effective on imipenem-resistant P.aeruginosa.The resistance of imipenem-resistant P.aeruginosato the aforementioned antibacterials was 60% or greater,and imipenem-resistant P.aeruginosa was completely resistant to ampicillin.Of 40 strains of imipenem-resistant P.aeruginosa,1（2.50%）tested positive for OXA-17.Thirteen strains tested positive for oprd2 gene deletion,and that gene was deleted in 32.50% of the strains.imp,vim,ges,and other resistance genes were not detected. Conclusion More attention should be paid to bacterial drug resistance and monitoring of that resistance should be enhanced.The rational use of antibacterials that P.aeruginosais more susceptible to could decrease the development of bacterial resistance to a certain extent.