阴沟肠杆菌产超广谱β内酰胺酶的研究

Investigation of extended spectrum β-lactamases in Enterobacter cloacae

目的了解我院2004年1—10月临床分离的83株阴沟肠杆菌中产ESBLs的情况,并对1株多重耐药菌株进行耐药机制研究。方法采用改良双纸片法(MDDT)进行ESBLs的初筛。以8对ESBLs引物(CTX-M,CTX-M-1,CTX-M-2,CTX-M-9,SHV,TEM,VEB,PER型)进行PCR扩增,对其中1株菌株(37号菌株)的扩增产物进行序列分析。结果MDDT初筛结果证明有43株菌产ESBLs,41株菌多种ESBLs引物均有扩增产物,序列分析表明37号阴沟肠杆菌携带的ESBLs为CTX-M-9,CTX-M-1样,SHV型。结论产多种ESBLs是引起该株阴沟肠杆菌对第三代头孢菌素耐药的重要原因。

Objective To investigate the mechanism of resistance to third-generation cephalosporins in 83 clinical isolates of Enterobacter cloacae. Methods Production of ESBLs were identified with modification of the double-disk test（MDDT）. Eight sets of primers （CTX-M, CTXM-1, CTX-M-2, CTX -M-9, SHV, TEM, VEB, PER） were used for PCR amplification. Gene clone and DNA sequencing were performed for one of the strains. Results MDDT was positive for 43 isolates of E. cloacae. Amplicons were gained by PCR amplification with CTX-M, CTX-M-1, CTX-M-9, SHV, TEM primers. DNA sequencing of the amplicons from the strain No. 37 revealed ESBLs of CTX-M-1 group, CTX-M-9 and SHV. Conclutions Production of multiple ESBLs may be the important reason for the resistance of the E. cloacae strain to third-generation cephalosporins.