Gene gyrA Mutation in Nalidixic acid-resistant Salmonella paratyphi A / 中华医院感染学杂志

ABSTRACT

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.