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目的对临床分离的26株头孢西丁高水平耐药肠杆菌属细菌进行检测,探讨其质粒型AmpCβ-内酰胺酶基因的分布。方法对2014年临床分离的头孢西丁MIC≥128μg/ml的26株肠杆菌属细菌进行检测,琼脂平皿二倍稀释法检测细菌的MIC,采用碱裂解变性法提纯质粒DNA,多重PCR法检测细菌上质粒型AmpCβ-内酰胺酶基因。结果对头孢西丁的MIC≥128μg/ml、对氨苄西林的MIC≥512μg/ml的菌株进行研究,头孢噻肟、头孢他啶、头孢吡肟和氨曲南的MIC90分别为512、64、32μg/ml和256μg/ml;26株肠杆菌属细菌中仅2株阴沟肠杆菌未检测到质粒型AmpC酶基因;分别有13、11株和4株肠杆菌属细菌检测到DHA、EBC和FOX条带;其中4株肠杆菌属细菌同时检测到两种基因,3株同时扩增到DHA和EBC条带。结论头孢吡肟可作为治疗该类细菌感染的首选药物;DHA、MIR-1、ACT-1型AmpCβ-内酰胺酶在肠杆菌属细菌中的分布相对较多。
Objective To investigate the distribution of 26 strains of cefoxitin resistant Enterobacteriaceae in clinical isolates and to explore the distribution of their plasmid type AmpC β - lactamase gene. Methods 26 strains of Enterobacteriaceae with cefoxitin MIC≥128μg / ml clinically isolated in 2014 were tested. The bacterial MICs were detected by double dilution method with agar plates. The plasmid DNA was purified by alkaline lysis method. The multiplex PCR was used to detect the bacteria The upper plasmid AmpC beta-lactamase gene. Results The MIC of cefoxitin was 128 μg / ml and the MIC of ampicillin was 512 μg / ml. The MIC90 of cefotaxime, ceftazidime, cefepime and aztreonam were 512, 64, 32 μg / ml And 256 μg / ml respectively; only 2 strains of Enterobacter cloacae in 26 strains of Enterobacteriaceae did not detect plasmid-like AmpC enzyme gene; DHA, EBC and FOX bands were detected in 13,11 and 4 strains of Enterobacter respectively; Four of the four Enterobacter bacteria simultaneously detected two genes, and three of them amplified to DHA and EBC bands at the same time. Conclusions Cefepime can be used as the drug of choice for the treatment of such bacterial infections. The distribution of DHA, MIR-1 and ACT-1 AmpC β-lactamases is relatively high in Enterobacteriaceae.