老年人呼吸道革兰阴性杆菌感染耐药机制研究

Resistance Mechanism of Gram-negtive Bacilli from Lower Respiratory Tract of Elderly In-patient

目的 研究老年人下呼吸道感染革兰阴性杆菌的耐药机制。方法 分别用双纸片增效确认试验 ,改良三维法、自动细菌鉴定和药敏系统 (VITEK)及 Etest方法测定耐药菌产酶情况。结果 80株肺炎克雷伯菌及 14 3株大肠埃希菌产超广谱 β-内酰胺酶 (ESBL s)率分别为 2 7.5 %和 2 8.7% ,CTX- M基因型分别占 4 8%和 5 6 % ;12 4株阴沟肠杆菌中有 2 1.8%单独高产 Amp C酶 ,8.1%单独产 ESBL s,3.2 %即产 ESBL s又高产 Am p C酶 ;71株耐亚胺培南的铜绿假单胞菌中有 18.3%产金属 β-内酰胺酶。结论 产 ESBL s、高产 Amp C酶和金属 β-内酰胺酶是住院老年患者下呼吸道感染的重要因素。

OBJECTIVETo investigate the resistance mechanism of G- bacteria from lower respiratory tract in elderly. METHODSDouble-disk test, three-dimensional extract test, VITEK and Etest were performed. RESULTS Among 80 strains of Klebsiella pneumoniae (27.5%) and 143 strains of Escherichia coli (28.7%) produced ESBLs, CTX-M accounted for 48% and 56%, respectively. Among 124 strains of Enterobacter cloacae isolates, 21.8% only produced high-level AmpC β-lactamases, 8.1% only produced ESBLs, 3.2% produced both high-level AmpC β-lactamases and ESBLs. Among 71 strains of Pseudomonas aeruginosa resistant to imipenem, 18.3% produced metallo-β-lactamases. CONCLUSIONS The result showed that the strains produced extended spectrum β-lactamases (ESBLs), high-level AmpC β-lactamases and metallo-β-lactamases are important causes for lower respiratory infection in the elderly in-patients.