肠杆菌属细菌高产AmpC酶和超广谱β-内酰胺酶的表达状况研究

目的 研究超广谱β-内酰胺酶（ESBLs）和高产AmpC酶在肠杆菌属细菌的表达状况以及ESBLs的基因型,了解肠杆菌属细菌对β-内酰胺类抗生素的耐药机制。方法 采用酶提取物三维及抑制试验检测121株肠杆菌属细菌高产AmpC酶和产ESBLs的情况;采用聚合酶链反应检测产ESBLs菌株的基因型。结果 在121株肠杆菌属细菌中,酶提取物三维及抑制试验共检出产ESBLs菌株29株（24.0%）,高产AmpC酶并产ESBLs菌株14株（11.5%）,高产AmpC酶并产ESBLs的菌株占总高产AmpC酶菌株的43.8%（14/32）。在25株PCR扩增阳性菌株中,TEM型为7株,SHV型10株,CTX-M-1组6株,CTX-M-13组7株,OXA组为阴性,其中有5株同时检测出两种ESBLs基因型。结论 除高产AmpC酶外,产ESBLs也是肠杆菌属细菌对β-内酰胺类抗生素耐药的重要因素之一。肠杆菌属细菌产ESBLs的基因型包括TEM、SHV、CTX-M型,以CTX-M型为主。

Study on the expression of high-level producing AmpC β-lactamase and ESBLs in Enterobacter

Objective To investigate the expression of ESBLs,their genetypes and high-level producing AmpC β-lactamase isolates in Enterobacter and probe into β-lactam antibiotics resistance mechanism of Enterobacter strains.Methods All of 121 Enterobacter isolates were detected by enzyme extract three dimensions and inhibition test to discriminate high-level producing AmpC β-lactamase and producing ESBLs isolates;genetypes of ESBLs were detected by polymerase chain reaction.Results Among 121 clinical isolates of Enterobacter,29 isolates(24.0%)produced ESBLs,14 isolates(11.5%)produced both high-level AmpC β-lactamase and ESBLs,and the isolates producing both high-level AmpC β-lactamase and ESBLs accounted for 43.8%(14/32)in high-level producing AmpC β-lactamase isolates.Among 25 positive isolates of PCR,7 isolates carried TEM-type ESBLs,10 isolates carried SHV-type ESBLs,13 isolates carried CTX-M-type ESBLs,and 5 isolates carried two kind of ESBLs genetypes.OXA-type ESBLs was negative in Enterobacter.Conclusions Producing ESBLs is also a significant factor of the resistance mechanism to β-lactam antibiotics in Enterobacter.The genetypes of ESBLs in Enterobacter!include TEM-type,SHV-type and CTX-M-type.