Study on the serotype, drug sensitivity and virulence genes of clinical isolates of Salmonella in Zhejiang Province / 中华传染病杂志

ABSTRACT

Objective:To investigate the serotype distribution, drug resistance and the virulence gene profiles of clinical isolates of Salmonella in Zhejiang Province. Methods:A retrospective study of 463 clinical isolates of Salmonella in nine regions of Zhejiang Province from 2010 to 2017 was conducted. Their serotypes were detected using the Kauffmann-White scheme based on serological detection. Antibiotics susceptibility tests were carried out using K-B disk diffusion method. Eleven virulence genes were detected by polymerase chain reaction. Results:A total of 35 serotypes were identified among the 463 strains of Salmonella. The dominant serotypes were Salmonella typhimurium (41.90%(194/463)) and Salmonella enteritis (22.25%(103/463)). The resistance rate of Salmonella to ampicillin was the highest (66.52%(308/463)), followed by ampicillin/sulbactam (46.87%(217/463)), while low resistance rate to piperacillin/tazobactam was observed (3.24%(15/463)). All strains were sensitive to imipenem and meropenem. Finally, 188 strains (40.60%) of multi-drug resistance were found. The virulence genes hilA, ssrB, marT, siiD, sopB and pagN were found in all Salmonella strains. The virulence gene vexA was found only in Salmonella typhi and Salmonella Dublin; virulence gene icmF was mainly found in Salmonella enteritis. The virulence plasmid gene spvB and pefA were mainly found in Salmonella enteritidis and Salmonella typhimurium and invariably appeared in pairs. The virulence gene cdtB was mainly found in Salmonella typhi and Salmonella paratyphi A. Conclusions:Salmonella typhimurium and Salmonella enteritis are the main clinically isolated Salmonella strains in Zhejiang Province. The situation of multi-drug resistance is severe and a variety of virulence genes are highly detected.