感染性心内膜炎患者分离株铜绿假单胞菌耐药基因研究

Study of genes responsible for the drug resistance of Pseudomonas aeruginosa in patients with infective endocarditis

目的研究感染性心内膜炎患者分离株铜绿假单胞菌的耐药基因和毒力基因及传播特点,为临床治疗及合理用药打下基础。方法采用琼脂稀释法测定铜绿假单胞菌对12种临床常用抗生素的敏感性,对exoU、exoS、exoT、exoY、toxA和Pyo等6种铜绿假单胞菌毒力基因和铜绿假单胞菌金属酶IMP和VIM基因进行PCR扩增。结果232株铜绿假单胞菌中有75株多重耐药株(MDR),占32.33%。多重耐药株对12种临床常用抗生素耐药率均超过40.00%,其中对环丙沙星和左氧氟沙星耐药率分别为44.00%和49.33%,对亚胺培南和美罗培南耐药率分别为94.67%和93.33%。碳青霉烯类抗生素敏感株对亚胺培南和美罗培南耐药率为0。75株多重耐药株中有32株毒力基因exoU呈阳性,37株毒力基因exoS呈阳性,28株毒力基因exoT呈阳性,11株毒力基因exoY呈阳性,35株毒力基因toxA呈阳性,18株毒力基因Pyo呈阳性。金属β内酰胺酶基因检测,其中21株IMP基因阳性,18株VIM基因阳性。结论心脏内膜炎患者治疗应及时做血培养并进行药敏试验,依据药敏性试验结果进行合理用药。医务人员应注意手部卫生管理,加强器械消毒及病房消毒隔离管理,以利于控制细菌金属β-内酰胺酶基因的传播。

Objective To study genes responsible for the drug resistance of Pseudomonas aeruginosafrom patients with infective endocarditis in order to lay the foundation for clinical treatment of infections and rational use of antibiotics.Methods The sensitivity of P.aeruginosato 12 clinical antibiotics was tested using the agar dilution method.Six genes responsible for the virulence of P.aeruginosa-exoU,exoS,exoT,exoY,toxA and Pyo-and the IMP and VIM genes responsible for metallo-β-lactamase production were amplified using PCR and analyzed using electrophoresis. Results Of232 strains of P.aeruginosa,75 were found to be multidrug-resistant（MDR）,accounting for 32.3% of the tested strains.The MDR strains were highly resistant to 12 clinical antibiotics,with a resistance higher than 40%.MDR strains were least resistant to ciprofloxacin（44%）and levofloxacin（49.3%）.In contrast,MDR strains were most resistant to imipenem（94.7%）and meropenem（93.3%）.Carbapenem-susceptible strains were resistant to imipenem and meropenem at a rate of 0%.Of the 75 strains,32had the exoU gene,37 had the exoS gene,28 had the exoT gene,11 had the exoY gene,35 had the toxA gene,18 had the Pyo gene,21 had the IMP gene,and 18 had the VIM gene. ConclusionTreatment of infective endocarditis should coincide with prompt blood cultures and drug sensitivity testing,with rational antibiotic use based on those results.Hospitals should have medical staff manage their hand hygiene,enhance sterilization of equipment,and disinfect and isolate wards in order to control the metallo-β-lactamase-producing P.aeruginosa.