It suggested that the level of resistance of isolates would be related to selecting pressure of fluoroquinolones and induced gene mutations of DNase and topoisomerase IV could not activate AcrAB efflux pump system.

• 提示临床分离的鸡大肠杆菌O 78的耐药水平与喹诺酮类药物的选择性压力有关,它诱导了DNA旋转酶和拓扑异构酶IV的基因突变,可能不能激活A crAB外输泵。