福氏志贺菌对诺氟沙星耐药性及耐药机制的研究

Study on the resistance to norfloxacin in Shigellae flexneri and its mechanism

目的研究福氏志贺菌对诺氟沙星的耐药性及耐药机制。方法收集福氏志贺菌３０株，进行抗菌药物敏感试验，４株耐药菌，１株敏感菌和福氏志贺菌标准菌５１５７３的ｇｙｒＡ基因的Ｎ末端编码区进行ＰＣＲ扩增并克隆和测序。结果福氏志贺菌对诺氟沙星的耐药率高达５３．３％，ｇｙｒＡ基因的序列分析结果揭示存在３个导致氨基酸改变的基因点突变：丝氨酸８３→亮氨酸，天冬氨酸８７→天冬酰氨，天冬氨酸８７→甘氨酸。结论福氏志贺菌对诺氟沙星已有较高的耐药性，ｇｙｒＡ基因点突变与福氏志贺菌对诺氟沙星的耐药性有关。

Objective In order to study the resistance of Shigellae flexneri to norfloxacin as well as its mechanism. Methods A total of 30 clinical isolates were collected. Susceptibility test was performed. The N terminal coding region of gyr A gene was amplified by PCR and coloned as well as sequenced in four norfloxacin resistant isolates, one norfloxacin sensitive isolate and shigellae 51573. Results The resistance rate of Shigellae flexneri isolates to norfloxacin was up to 53.3%. DNA sequence analysis of gyr A gene revealed three mutations that resulted in amino acid change: Ser 83→Leu, Asp 87→Asn, Asp 87→Gly. Conclusion Shigellae flexneri isolates have had high resistance rate to norfloxacin and gyr A gene mutations were implicated in norfloxacin resistance of Shigellae flexneri.