Summer Buzz

Polyxeni Potter

Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Multidrug-Resistant Atypical Variants of Shigella flexneri in China

Shaofu Qiu¹, Yong Wang¹, Xuebin Xu¹, Peng Li¹, Rongzhang Hao¹, Chaojie Yang¹, Nan Liu¹, Zhenjun Li¹, Zhongqiang Wang¹, Jian Wang¹, Zhihao Wu¹, Wenli Su¹, Guang Yang¹, Huiming Jin¹, Ligui Wang¹, Yansong Sun, Zhengan Yuan, Liuyu Huang, and Hongbin Song

Author affiliations: Academy of Military Medical Sciences, Beijing, China (S. Qiu, Y. Wang, P. Li, R. Hao, C. Yang, N. Liu, Z. Wang, J. Wang, Z. Wu, W. Su, G. Yang, L. Wang, Y. Sun, L. Huang, H. Song); Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China (X. Xu, H. Jin, Z. Yuan); Chinese Center for Disease Control and Prevention, Beijing (Z. Li)

Abstract

We identified 3 atypical Shigella flexneri varieties in China, including 92 strains with multidrug resistance, distinct pulse types, and a novel sequence type. Atypical varieties were prevalent mainly in developed regions, and 1 variant has become the dominant Shigella spp. serotype in China. Improved surveillance will help guide the prevention and control of shigellosis.

Each year worldwide, ≈1.5 million children <5 a="" age="" diarrheal="" die="" diseases="" from="" href="http://wwwnc.cdc.gov/eid/article/19/7/11-1221_article.htm?s_cid=eid-gDev-email#r1" of="" title="1" years="">1

), which is of particular concern in developing countries. Shigella spp. are leading bacterial causes of diarrhea, responsible for >80 million cases of bloody diarrhea and 700,000 deaths each year (2), and S. flexneri serotype 2a has been recognized as the most prevalent serotype in China for many years (3). To better understand the etiology of bacterial diarrhea in China and to determine if S. flexneri serotype 2a is still the most prevalent serotype in China, we conducted a study during May 2008–December 2010.

The Study

A total of 10,021 fecal samples were obtained from patients with diarrhea or dysentery at hospitals in 8 provinces within the eastern, southern, western, northern, and central regions of China: Liaoning, Shandong, Jiangsu, Guangdong, Gansu, Sichuan, Xinjiang, and Hebei Provinces. Samples were screened for the presence of Shigella spp. by using API 20E strips (bioMérieux, Marcy l’Etoile, France). Serotyping was performed by using 1) an antisera kit specific for all type- and group-factor antigens (Denka Seiken, Tokyo, Japan) and 2) a panel of monoclonal antibodies against S. flexneri (MASF; Reagensia AB, Stockholm, Sweden). Antimicrobial susceptibility testing was performed by the disk diffusion method as described (4). Genetic relationships were estimated by using multilocus sequence typing, as described (5), and pulsed-field gel electrophoresis (PFGE) (6).