耐萘啶酸甲型副伤寒沙门菌gyrA基因突变研究

目的 研究绍兴地区耐萘啶酸甲型副伤寒沙门菌(SPA)gyrA基因突变情况.方法 对52株SPA进行基因扩增,PCR产物纯化后进行双向测序,用OMIGA2.0软件对DNA促旋酶A亚单位序列进行分析比对,确定gyrA基因突变.结果 耐萘啶酸SPA在gyrA喹诺酮类耐药决定区(QRDR)氨基酸残基83或87位点发生点突变;其中51株在83位发生突变,1株在87位点发生突变;未发现两个位点同时突变菌株;gyrA QRDR其他部位未发现突变.结论 gyrA基因83位突变与SPA耐萘啶酸有直接关系,gyrA基因87位单突变也可导致对萘啶酸耐药;绍兴地区近两年耐萘啶酸SPA主要为83位的TCC→TTC(Ser→Phe)突变.

Gene gyrA Mutation in Nalidixic acid-resistant Salmonella paratyphi A

OBJECTIVE To explore the gene gyrA mutation in nalidixic acid-resistant Salmonella paratyphi A (SPA) in Shaoxing area. METHODS Fifty-two strains of SPA gene were assessed by amplification and purification and the PCR products were detected by two directional sequencing methods. The sequences of DNA gyrase A were compared and analyzed with the OMIGA2.0 software, and the gene gyrA mutation was identified. RESULTS The mutation in nalidixic acid-resistant SPA was discovered in No. 83 or No. 87 animo acid site of gyrA quinolones resistant determinate region (QRDR), and the mutation of 51 strains occurred in No. 83 site, 1 strain occurred in No. 87 site. The simultaneous mutation of two sites was not discovered, No mutations were found in other sites of gyrA QRDR. CONCLUSIONS No. 83 site mutations of gene gyrA has a direct relation to nalidixic acid-resistant SPA. No. 87 site mutation of gene gyrA might also cause nalidixic acid-resistantce. The nalidixic acid-resistant SPA is mainly mutated in No. 83 site by TCC→TTC (Ser→Phe) in Shaoxing area.