联合应用抗生素测定并鉴别超广谱和Ⅰ型β—内酰胺酶

目的：联合用抗生素测定并鉴别大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌产生的超广谱和Ⅰ型β－内酰胺酶。方法：用头孢噻肟（TX）、头孢他定（CTD）、氨曲南（ATN）、奥格门丁（AOA）、头孢西丁（CXT）和亚胺培能在MH琼脂上进行双纸片搭格耕检测和鉴别大肠埃希菌、肺炎克雷伯菌、沟沟肠杆菌的超广β－内酰胺酶（ESBLs)及Ⅰ型β－内酰胺酶。结果：265株大肠埃希菌、95株肺炎克雷伯菌、67株阴沟肠杆菌均对亚胺培能敏感；对三代头孢菌素的耐药率分别为23．4％、36．8％、58．2％，产生的能水解超广谱β－内酰胺类抗生素的β－内酰胺酶可分为两类，这些菌株对CXT有不同的耐药性，CTX＋CTD＋ATN的ESBLs检出率与单一CTX、CTD、ATN的检出率差异有显性，与CTX＋CTD的ESBLs检出率差异无显性（P＞0．05）。结论：应用不同抗生素可将水解超广谱β－内酰胺类抗生素的β－内酰胺酶分为ESBLs和Ⅰ型，有不同的耐药特点；联合应用两种以抗生素可提高检出率，双纸片搭桥法适合临床使用，临床分离菌株应用将超广谱和Ⅰ型β－内酰胺酶的检测作为常规。

Detection and classification for extended-spectrum and

Objective：Detection for extended-spectrum β-lactamases（ESBLs） and Ⅰtype β-lactam ase s from Eschrichia coli Klebsiella pneumoniae Enterobacter cloacae using varie d antibiotics.Methods：ESBLs and Ⅰtype β-lactamases from E.coli,K.pneumonia e and E.cloacae was detected by double-disk(DD) potentiation procedure and rule v itro-sensitive test.Cefotaxime(CTX), ceftazidime(CTD),aztreonam(ATN),augmentin( AOA),cefoxitin(CXT) and imipenem were used in this test.Results：Imipenem is sensitive for all strain at this test.23.4% Eschrichia coli 36.8% Klebsiella pneumoniae,and 58.2% Enterobacter cloacae res isted 3rd cephalosporins, the resistance for cefoxitin is different. The　β -lac tamases of hydrolyses extended-spectrum β-lactams is divided into two types.Th e rate of detection was higher by using CTX and CTD and ATN than using CTD or CT X or ATN only(χ2=5.14，P<0.05、χ2=21.04，P<0 .01、χ2=62.02，P <0.01),but not different from using CTX and CTD（χ2=0.5，P>0.05）.Conclusion：The ESBLs and Ⅰtype β-lactamases could be differe nt by using varied antibiotics,they have different resistance to antibiotics . U sing more than two　β-lactams antibiotis, the positive rate of ESBLs isolate i s r aised The double-disk(DD) method is practical for clinical detection of ESBLs- produ cing isolates of Enterobateriaceae. The detection of ESBLs and Ⅰtype β-lactam ases should be conducted for clinical isolate