F33: A-: B-, IncHI2/ST3, and IncI1/ST71 plasmids drive the dissemination of fosA3 and bla CTX-M-55/-14/-65 in Escherichia coli from chickens in China.

Xiaoyun Yang,Jianxia Hou,Yiyun Liu,Yinjuan Tan,Li Xing,Jing Wang,Dandan He,Luchao Lv,Jian-Hua Liu,Xiaojie Chen,Wuling Liu,Zhenling Zeng,Tong Yang

doi:10.3389/fmicb.2014.00688

Xiaoyun Yang, Jianxia Hou + Show 11 more

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https://doi.org/10.3389/fmicb.2014.00688

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Abstract

The purpose of this study was to examine the occurrence of fosfomycin-resistant Escherichia coli from chickens and to characterize the plasmids carrying fosA3. A total of 661 E. coli isolates of chicken origin collected from 2009 to 2011 were screened for plasmid-mediated fosfomycin resistance determinants by PCR. Plasmids were characterized using PCR-based replicon typing, plasmid multilocus sequence typing, and restriction fragment length polymorphisms. Associated addiction systems and resistance genes were identified by PCR. PCR-mapping was used for analysis of the genetic context of fosA3. Fosfomycin resistance was detected in 58 isolates that also carried the fosA3 gene. Fifty-seven, 17, and 52 FosA3-producers also harbored blaCTX−M, rmtB, and floR genes, respectively. Most of the 58 fosA3-carrying isolates were clonally unrelated, and all fosA3 genes were located on plasmids belonged to F33:A-:B- (n = 18), IncN-F33:A-:B- (n = 7), IncHI2/ST3 (n = 10), IncI1/ST71 (n = 3), IncI1/ST108 (n = 3), and others. The genetic structures, IS26-ISEcp1-blaCTX−M−55-orf477-blaTEM-1-IS26-fosA3-1758bp-IS26 and ISEcp1-blaCTX−M−65-IS903-iroN-IS26-fosA3-536bp-IS26 were located on highly similar F33:A-:B- plasmids. In addition, blaCTX−M−14-fosA3-IS26 was frequently present on similar IncHI2/ST3 plasmids. IncFII plasmids had a significantly higher frequency of addiction systems (mean 3.5) than other plasmids. Our results showed a surprisingly high prevalence of fosA3 gene in E. coli isolates recovered from chicken in China. The spread of fosA3 can be attributed to horizontal dissemination of several epidemic plasmids, especially F33:A-:B- plasmids. Since coselection by other antimicrobials is the major driving force for the diffusion of the fosA3 gene, a strict antibiotic use policy is urgently needed in China.

Highlights

The increasing occurrence of bacterial infections caused by multidrug resistant gram-negative Enterobacteriaceae (MDR-GNB) has reignited interest in the old antibiotic, fosfomycin (Falagas et al, 2010)
Fosfomycin use in animals is prohibited in China, a high prevalence of the plasmid-mediated fosfomycin-resistance gene fosA3 was observed in E. coli isolates from pet in China (Hou et al, 2012)
In this study, we investigated the prevalence of fosfomycin resistance in E. coli isolated from chickens from 2009 to 2011 in China

Summary

Introduction

The increasing occurrence of bacterial infections caused by multidrug resistant gram-negative Enterobacteriaceae (MDR-GNB) has reignited interest in the old antibiotic, fosfomycin (Falagas et al, 2010). Fosfomycin use in animals is prohibited in China, a high prevalence of the plasmid-mediated fosfomycin-resistance gene fosA3 was observed in E. coli isolates from pet in China (Hou et al, 2012). The frequency of blaCTX−M in E. coli isolated from food animals in China has generally been reported to be low prior to 2008, but has increased in prevalence in recent years, especially in chicken isolates (Liu et al, 2007; Li et al, 2010; Zheng et al, 2012). To determine if the occurrence of fosfomycin resistance has increased with the increasing frequency of blaCTX−M in food animal isolates in recent years, we screened E. coli isolates of chicken origin collected during 2009– 2011 for fosfomycin resistance and plasmid-mediated fosfomycin resistance genes. Characterization of fosA3-encoding plasmids as well as the association of fosA3 with other resistance genes, such as blaCTX−M, was examined

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