Antibiotic resistance and molecular epidemiology tracing classification of Shigella sonnei epidemic strains isolated in Hunan Province, 2013-2016
XIA Xin, QIN Di, HE Zi-xiang, CAI Liang, ZHAN Zhi-fei
Key Laboratory of Microbial Molecular Biology of Hunan Province, Hunan Provincial Center for Disease Control and Prevention, Changsha, Hunan 410005, China
Abstract：Objective To investigate the drug resistance characteristics of Shigella sonnei epidemic strains isolated in Hunan Province from 2013 to 2016 and their relationship with molecular epidemiology. Methods Shigella sonnei strains isolated from the diarrhea epidemics in Hunan Province from 2013 to 2016 were identified by biochemical and serological tests, and then were tested for drug susceptibility and for molecular typing by pulsed-field gel electrophoresis (PFGE). Results Forty strains of Shigella sonnei were identified by serological and biochemical tests. All the strains were resistant to ampicillin and gentamicin, and highly resistant to sulfamethoxazole (SMZ) and ampicillin/sulbactam, with the resistance rates being 90.0% and 82.5% respectively. All the strains were sensitive to piperacillin/tazobactam, ceftazidime, aztreonam, ertapenem, imipenem, ciprofloxacin, levofloxacin and nitrofurantoin. Some strains were resistant to cephalosporins and aminoglycoside antibiotics to different degrees. PFGE showed that the 40 strains had 7 banding patterns, the similarity degree reached 80.89%-100%, and each epidemic had its dominant strains. Some strains isolated from the patients shared the same PFGE band types with those from food or well water samples collected during the same period, and there was a certain degree of genetic relevance among the epidemic strains. Conclusions More attention should be paid to the rising trend of antibiotic resistance rate of Shigella sonnei during 2013-2016. The plague strains are highly correlated with the food and water contaminated by Shigella sonnei, and there is a certain genetic relationship among the epidemic strains in different areas. It is necessary to continually monitor the molecular typing.
2017, Vol. 24 
