Emergence and Diversity of Salmonella enterica Serovar Indiana Isolates with Concurrent Resistance to Ciprofloxacin and Cefotaxime from Patients and Food-Producing Animals in China

Li Bai(China National Center for Food Safety Risk Assessment), Jiayong Zhao(Henan Provincial Center for Disease Control and Prevention), Xin Gan(China National Center for Food Safety Risk Assessment), Juan Wang(China National Center for Food Safety Risk Assessment), Xiuli Zhang(Henan Provincial Center for Disease Control and Prevention), Shenghui Cui(National Institutes for Food and Drug Control), Shengli Xia(Henan Provincial Center for Disease Control and Prevention), Yujie Hu(China National Center for Food Safety Risk Assessment), Shaofei Yan(China National Center for Food Safety Risk Assessment), Jiahui Wang(China National Center for Food Safety Risk Assessment), Fengqin Li(China National Center for Food Safety Risk Assessment), Séamus Fanning(University College Dublin), Jin Xu(China National Center for Food Safety Risk Assessment)
Antimicrobial Agents and Chemotherapy
March 22, 2016
10.1128/aac.02849-15
Cited by 86Open Access
Full Text

Abstract

Salmonellosis is a major global foodborne infection, and strains that are resistant to a great variety of antibiotics have become a major public health concern. The aim of this study was to identify genes conferring resistance to fluoroquinolones and extended-spectrum β-lactams in nontyphoidal Salmonella (NTS) from patients and food-producing animals in China. In total, 133 and 21 NTS isolates from animals and humans, respectively, exhibiting concurrent resistance to ciprofloxacin and cefotaxime were cultured independently from 2009 to ∼2013. All of the isolates were identified, serotyped, and subjected to antimicrobial susceptibility testing. Importantly, the isolates with concurrent resistance to ciprofloxacin and cefotaxime all were confirmed as S. enterica serovar Indiana. The presence of fluoroquinolone resistance genes and extended-spectrum β-lactamases (ESBLs) was established by PCR and DNA sequencing. The occurrence and diversity of different genes conferring fluoroquinolone resistance [qepA, oqxAB, and aac(6')-Ib-cr] with mutations in topoisomerase-encoding genes (gyrA and parC) and several ESBLs (including CTX-M-65, CTX-M-27, CTX-M-15, CTX-M-14, and CTX-M-14/CTX-M-15) were noteworthy. Genes located on mobile genetic elements were identified by conjugation and transformation. Pulsed-field gel electrophoresis, used to determine the genetic relationships between these isolates, generated 91 pulsotypes from 133 chicken isolates and 17 pulsotypes from the 21 clinical isolates that showed considerable diversity. Analysis of the pulsotypes obtained with the isolates showed some clones appeared to have existed for several years and had been disseminating between humans and food-producing animals. This study highlights the emergence of ciprofloxacin- and cefotaxime-resistant S. enterica serovar Indiana, posing a threat to public health.

Related Papers

No related papers found

Powered by citation graph analysis