儿童感染肺炎克雷伯菌产AmpC酶和ESBLs的检测及耐药性分析

目的了解广州地区儿童感染肺炎克雷伯菌产质粒介导的AmpC酶和超广谱β-内酰胺酶（ESBLs）的情况及其耐药特征，为临床合理用药提供参考依据。方法采用标准纸片扩散法检测ESBLs，头孢西丁三维试验法检测AmpC酶，K—B纸片法测定肺炎克雷伯菌对抗菌药物的敏感性。结果共检出248株肺炎克雷伯菌，其中46株产AmpC酶，阳性率为18．5％；157株产ESBLs，阳性率为63．3％；同时产AmpC酶和ESBLs菌株阳性率为18．1％。产AmpC酶肺炎克雷伯菌对第三代头孢菌素高度耐药。耐药率达80％～100％；对头孢吡肟、含酶抑制剂复合药的耐药率也在56．5％～93．5％之间：但对环丙沙星、阿米卡星的耐药率则在30％以下，对亚胺培南全部敏感。产ESBLs菌株对头孢菌素、含酶抑制剂复合药的耐药率也较高，在50％-91．7％之间，但对阿米卡星、环丙沙星、亚胺培南仍高度敏感。ESBLs阴性肺炎克雷伯菌对所测抗生素的敏感率均在81．2％以上。产酶菌株耐药率明显比非产酶菌株高。结论广州地区儿童感染肺炎克雷伯菌产ESBLs和AmpC酶的状况已十分突出：产酶菌株对常用抗生素的耐药率较高；碳青霉烯类抗生素可作为治疗产AmpC酶和／或ESBLs肺炎克雷伯菌感染的经验用药。

Detection of AmpC and Extended-spectrum Beta-lactamases in Klebsiella pneumoniae Isolated from Children

Objective To investigate the prevalence of AmpC beta-lactamases and extended-spectrum beta-lactamases （ESBLs） produced by Klebsiella pneumoniae isolated from children living in Guangzhou and to evaluate the extent of antibiotic resistance of the isolates. Method Antibiotic susceptibility of K.pneumoniae was determined by the Kirby-Bauer methods. AmpC beta-lactamases was detected by three-dimensional extract test. ESBLs was confirmed by dish diffusion test. Result Among the 248 isolates, the prevalence of AmpC and ESBLs producing K.pneumoniae was 18.5% and 63.3%, respectively. 18.1% of the isolates produced both AmpC and ESBL. The percentage of cephalosporins and cefepime, cefoperazone/sulbactam resistant AmpC-produeing strains was 56.5%- 100%, respectively. However, the percentage of Amikacin and ciprofloxacin resistant strains was lower than 30%. The resistant rate of ESBLs producers to cephalosporins, cefoperazone/sulbactam was in the ranged of 50% to 91.7%, to Amikacin and ciprofloxacin was 11.5% and 10.3%, respectively. Imipenem-resistant strain was not detected. The antibiotics sensitivity of ESBLs negative isolates was in the range of 81.2% to 100%. Conclusion The incidence of AmpC and ESBLs-producing K.pneumoniae isolated from children was relatively high in Guangzhou. The beta-lactamases producing strains were highly resistant to the commonly used antibiotics. Carbopenems may be used in the treatment of infections caused by AmpC and/or ESBLs-producing K.pneurnoniae.