耐亚胺培南铜绿假单胞菌的耐药性及耐药基因分析

目的了解耐亚胺培南铜绿假单胞菌（IRPa）β-内酰胺类酶的表达情况,比较产酶菌和非产酶菌的耐药性,并探讨产AmpC酶基因对其耐药表型的影响。方法采用EDTA协同试验检测β-内酰胺类酶,PCR扩增β-内酰胺类酶耐药基因及其序列测定确定其基因型。结果 112株耐亚胺培南铜绿假单胞菌中检出产β-内酰胺类酶菌85株（75.9%）,产酶菌株的耐药性比非产酶菌株的耐药性明显严重,对替卡西林/克拉维酸、头孢吡肟、头孢他啶、阿米卡星、庆大霉素、妥布霉素、环丙沙星耐药率均大于35.3%;耐药基因TEM、SHV、OXAI、MP-1、AmpC、VIM-2阳性率分别为53.57%、10.17%、2.71%、4.46%、46.43%、16.96%,且有42.85%的菌株表现为多基因耐药。结论产β-内酰胺酶菌株对大多数抗生素的耐药性明显高于非产酶菌株,耐药基因以产TEM、AmpC为主,少部分产SHV、OXA、IMP-1、VIM-2,产β-内酰胺酶是铜绿假单胞菌对亚胺培南耐药的重要机制。

Antibiotic Resistance and Resistance Genes in Imipenem Resistant Pseudomonas aeruginosa

Objective To investigate the expression situation of imipenem resistant Pseudomonas aeruginosa(IRPa),to compare the antibiotic susceptibility of β-lactamases producing strains with that of non-β-lactamases producing strains,and to explore the effect of β-lactamases genes on drug-resistant phenotype. Methods EDTA synergism testing was used to detect β-lactamases and PCR was applied to β-lactamase gene amplification.DNA sequencing was carried out for genotyping of β-lactamases. Results Among the 112 strains of IRPa isolates,85(75.9%) produced β-lactamase.β-lactamase-producing IRPa had a more significant multi-drug resistance than those of non-β-lactamases-producing ones.The antibiotics susceptibility results demonstrated that the resistant rates to ticarcillin/clavulanic acid,cefepime,ceftazidime,amikacin,gentamycin,tobramycin,and ciprofloxacin were beyond 35.3%.The positive rates of resistance genes,TEM,SHV,OXA,IMP-1,Amp C,and VIM-2 were 53.57%,10.17%,2.71%,4.46%,46.43%,and 16.96%,respectively.In addition,there were 42.85% strains showed multiple resistance genes. Conclusions β-lactamases producing stains are more resistant to most antibiotics than non-β-lactamases-producing stains.TEM and AmpC are the primary resistance genes,while the resistance genes of SHV,OXA,IMP-1 and VIM-2 are subordinate.The presence of β-lactamases is the important drug resistant mechanism in IRPa.