title: Antimicrobial Resistance of Shigella flexneri Serotype 1b Isolates in China.
abstract: Shigella flexneri serotype 1b is among the most prominent serotypes in developing countries, followed by serotype 2a. However, only limited data is available on the global phenotypic and genotypic characteristics of S. flexneri 1b. In the present study, 40 S. flexneri 1b isolates from different regions of China were confirmed by serotyping and biochemical characterization. Antimicrobial susceptibility testing showed that 85% of these isolates were multidrug-resistant strains and antibiotic susceptibility profiles varied between geographical locations. Strains from Yunnan were far more resistant than those from Xinjiang, while only one strain from Shanghai was resistant to ceftazidime and aztreonam. Fifteen cephalosporin resistant isolates were identified in this study. ESBL genes (blaSHV, blaTEM, blaOXA, and blaCTX-M) and ampC genes (blaMOX, blaFOX, blaMIR(ACT-1), blaDHA, blaCIT and blaACC) were subsequently detected among the 15 isolates. The results showed that these strains were positive only for blaTEM, blaOXA, blaCTX-M, intI1, and intI2. Furthermore, pulsed-field gel electrophoresis (PFGE) analysis showed that the 40 isolates formed different profiles, and the PFGE patterns of Xinjiang isolates were distinct from Yunnan and Shanghai isolates by one obvious, large, missing band. In summary, similarities in resistance patterns were observed in strains with the same PFGE pattern. Overall, the results supported the need for more prudent selection and use of antibiotics in China. We suggest that antibiotic susceptibility testing should be performed at the start of an outbreak, and antibiotic use should be restricted to severe Shigella cases, based on resistance pattern variations observed in different regions. The data obtained in the current study might help to develop a strategy for the treatment of infections caused by S. flexneri 1b in China.
authors.affiliation: Department of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China; Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Xianyan
authors.initials: X
authors.lastname: Cui
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Chaojie
authors.initials: C
authors.lastname: Yang
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Liang
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Shengjie
authors.initials: S
authors.lastname: Yi
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xie
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Leili
authors.initials: L
authors.lastname: Jia
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Rongzhang
authors.initials: R
authors.lastname: Hao
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Ligui
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Yuejin
authors.initials: Y
authors.lastname: Hua
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Shaofu
authors.initials: S
authors.lastname: Qiu
authors.affiliation: Department of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Song
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D002511:Cephalosporins / Q000494:pharmacology; D002681:China / Q000453:epidemiology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004405:Dysentery, Bacillary / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D016521:Electrophoresis, Gel, Pulsed-Field; D015870:Gene Expression; D006801:Humans; D032023:Integrons; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D010957:Plasmids / Q000737:chemistry* / Q000378:metabolism; D065288:Serogroup; D012763:Shigella flexneri / Q000145:classification* / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D001618:beta-Lactamases