Pulsed field gel electrophoresis typing and drug resistance detection of Shigella sonnei isolated in Beijing, 2010-2015

Objective To understand the molecular and drug resistant characteristics of Shigella sonnei isolated in Beijing from 2010 to 2015. Methods A total of 259 Shigella sonnei strains isolated in Beijing from 2010 to 2015 were tested by pulsed field gel electrophoresis (PFGE) and the minimum inhibitory concentration of 12 antibiotics to the strains were detected after the serological and biochemical identification. Results PFGE results showed that the strains shared high homology (90%) and cluster A and B were the two major subtypes. The proportion of the strains in cluster A increased from 2010 to 2015. There were 257 drug resistant strains and 245 multidrug resistant strains (95.33%). It was noticeable that the drug resistant rate to ceftriaxone was in increase. Conclusion Shigella sonnei isolated in Beijing from 2010 to 2015 shared high homology, and cluster A was the predominant subtype. The increased rate of drug resistance to ceftriaxone might be related with the common clinical use of three-generation cephalosporin and increase of the strains in cluster A. Multidrug resistance was more complex, suggesting the importance of rational use of antibiotics.