pneumoniae producting ESBLs. The genes encoding ESBLs were amplified by polymerase chain reaction (PCR). The target amplification fragment was digested with two restriction endonucleases and then cloned into pUC19 vector.

• 用双纸片法初筛检测产ESBLs菌株 ,聚合酶链反应扩增ESBLs编码基因片段 ,并将其克隆至pUC19载体中 ,双脱氧链终止法测定核苷酸序列以确定亚型。