Distribution of ExPEC Virulence Factors, bla CTX-M, fosA3, and mcr-1 in Escherichia coli Isolated From Commercialized Chicken Carcasses.

Paula Signolfi Cyoia,Gerson Nakazato,Erick Kenji Nishio,Kelly Cristina Tagliari De Brito,Vanessa Lumi Koga,Renata Katsuko Takayama Kobayashi,Charles M Dozois,Sébastien Houle,Benito Guimarães De Brito

doi:10.3389/fmicb.2018.03254

Abstract

Pathogenic Escherichia coli found in humans and poultry carcasses harbor similar virulence and resistance genes. The present study aimed to analyze the distribution of extraintestinal pathogenic E. coli (ExPEC) virulence factors (VF), blaCTX−M groups, fosA3, and mcr-1 genes in E. coli isolated from commercialized chicken carcasses in southern Brazil and to evaluate their pathogenic risk. A total of 409 E. coli strains were isolated and characterized for genes encoding virulence factors described in ExPEC. Results of antimicrobial susceptibility testing confirmed that the strains were resistant to β-lactams, fosfomycin, colistin, and others resistance groups. The highest prevalence of VFs was observed in isolates belonging to the CTX-M groups, especially the CTX-M-2 group, when compared to those in other susceptible strains or strains with different mechanisms of resistance. Furthermore, ESBL strains were found to be 1.40 times more likely to contain three to five ExPEC virulence genes than non-ESBL strains. Our findings revealed the successful conjugation between ESBL-producing E. coli isolated from chicken carcass and the E. coli recipient strain J53, which suggested that genetic determinants encoding CTX-M enzymes may have originated from animals and could be transmitted to humans via food chain. In summary, chicken meat is a potential reservoir of MDR E. coli strains harboring resistance and virulence genes that could pose serious risks to human public health.

Highlights

Humans and warm-blooded animals naturally harbor bacteria in their intestines, such as Escherichia coli, which is usually a non-pathogenic commensal bacterium
Present study aimed to analyze the distribution of extraintestinal pathogenic E. coli (ExPEC) virulence factors (VF), blaCTX−M groups, and the fosA3 and mcr-1 genes in E. coli isolated from chicken carcasses commercialized in southern Brazil (States of Paraná-PR, Santa Catarina-SC, and Rio Grande do Sul-RS)
We identified multidrug-resistant E. coli strains from chicken carcasses from PR, SC and RS (82, 53, and 80%, respectively)

Summary

Introduction

Humans and warm-blooded animals naturally harbor bacteria in their intestines, such as Escherichia coli, which is usually a non-pathogenic commensal bacterium. E. coli could cause extraintestinal diseases, including urinary tract infection, septicemia and meningitis in humans or even colibacillosis in poultry, which is attributed to the acquisition of virulence factors (VFs) (Müller et al, 2016). Extraintestinal pathogenic E. coli (ExPEC) strains are characterized by several VF, including adhesins, invasins, protectins, and toxins, as well as several uptake systems for essential nutrients, such as iron (iron-uptake systems) (Johnson et al, 2008b). In addition to VFs, the spread of resistance elements among human pathogens may be related to the Enterobacteriaceae family, in which E. coli belongs. Most commonly detected CTX-M groups include CTX-M-1, CTX-M-2, CTX-M8, CTX-M-9, and CTXM-25 (Saravanan et al, 2018)

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