小儿呼吸道感染肺炎克雷伯杆菌耐药性和基因型研究

目的探讨临海地区小儿呼吸道感染肺炎克雷伯杆菌产超β-内酰胺酶（ESBLs和AmpC酶）的耐药性及耐药基因型分布情况。方法采用VITEK-60型全自动细菌鉴定仪鉴定细菌，按CLSI推荐的确证试验检测ESBLs和K-B纸片法测定药敏结果；采用头孢西丁纸片扩散法筛选产AmpC酶阳性菌株，采用PCR检测AmpC酶基因，并对产物进行测序分析基因型。结果113株肺炎克雷伯杆菌ESBLs和AmpC酶总检测率分别为29．20％和18．58％，其中单产ESBLs、单产AmpC酶和同产AmpC酶＋ESBLs检出率分别为23．01％、12．39％和6．19％；AmpC酶阳性菌株的耐药基因型：16株为DHA-1型，5株为ACT-1型。药敏试验：所分离的肺炎克雷伯杆菌对亚胺培南全部敏感，对喹诺酮类耐药率很低，对大多β-内酰胺类抗生素耐药率较高，并且产酶株的耐药性明显高于非产酶株，耐药现象在同产ES-BLS和AmpC酶菌株中更为严重。结论临海地区小儿呼吸道分离的肺炎克雷伯杆菌产ESBLs和AmpC酶检出率较高；AmpC酶以DHA-1基因型流行为主，产酶株呈现出高度多重耐药性。

Drug resistance and genotype of Klebsiella pneumonia in children with respiratory tract infection

Objective To investigate the resistance and resistant genotype distribution of Klebsiella pneumoniae producing ultra-β-lactamases(ESBLs and AmpC enzymes) in children with respiratory tract infections in Linhai.Method VITEK-60 Automatic bacterial identification instrument was used to identify the ESBLs bacteria according to the CLSI-recommended confirmatory test detected,and K-B disk method was used to determine the susceptibility;Cefoxitin disk diffusion method was used to screen AmpC-producing strains,and PCR was used to detect AmpC enzyme gene;the products were sequenced for genotypes.Result Of the 113 strains of Klebsiella pneumonia,the total detection rates of ESBLs and AmpC were 29.20% and 18.58% respectively,in which the rates of ESBLs,AmpC enzymes and AmpC enzyme+ESBLs were 23.01%,12.39% and 6.19%,respectively.The resistant genotypes of AmpC-positive strains were DHA-1(16 strains) and ACT-1(5 strains).All the Klebsiella pneumoniae isolated were sensitive to imipenem;The resistance was very low to quinolones,while higher to most β-lactam antibiotics,and the enzyme-producing strains were significantly more resistant than non-enzyme producing strains.The drug resistance of the strains producing both ESBLs and AmpC was the highest.Conclusion The detection rate of ESBLs and/or AmpC enzyme producing Klebsiella pneumonia isolated from pediatric respiratory,tracts was high in Linhai region.DHA-1 was the main genotype among AmpC enzyme,and the enzyme producing strains showed a high degree of multi-drug resistance.