Characteristics of Quinolone Resistance in Escherichia coli Isolates from Humans, Animals, and the Environment in the Czech Republic.

Magdalena Röderova,Vojtech Hanulik,Ivan Literak,Vendula Pudova,Pavel Sauer,Martina Masarikova,Monika Dolejska,Milan Kolar,Dana Halova,Miroslava Htoutou-Sedlakova,Alois Cizek,Petr Broz,Jan Bardon,Ivo Papousek

doi:10.3389/fmicb.2016.02147

Abstract

Escherichia coli is a common commensal bacterial species of humans and animals that may become a troublesome pathogen causing serious diseases. The aim of this study was to characterize the quinolone resistance phenotypes and genotypes in E. coli isolates of different origin from one area of the Czech Republic. E. coli isolates were obtained from hospitalized patients and outpatients, chicken farms, retailed turkeys, rooks wintering in the area, and wastewaters. Susceptibility of the isolates grown on the MacConkey agar with ciprofloxacin (0.05 mg/L) to 23 antimicrobial agents was determined. The presence of plasmid-mediated quinolone resistance (PMQR) and ESBL genes was tested by PCR and sequencing. Specific mutations in gyrA, gyrB, parC, and parE were also examined. Multilocus sequence typing and pulsed-field gel electrophoresis were performed to assess the clonal relationship. In total, 1050 E. coli isolates were obtained, including 303 isolates from humans, 156 from chickens, 105 from turkeys, 114 from the rooks, and 372 from wastewater samples. PMQR genes were detected in 262 (25%) isolates. The highest occurrence was observed in isolates from retailed turkey (49% of the isolates were positive) and inpatients (32%). The qnrS1 gene was the most common PMQR determinant identified in 146 (56%) followed by aac(6′)-Ib-cr in 77 (29%), qnrB19 in 41 (16%), and qnrB1 in 9 (3%) isolates. All isolates with high level of ciprofloxacin resistance (>32 mg/L) carried double or triple mutations in gyrA combined with single or double mutations in parC. The most frequently identified substitutions were Ser(83)Leu; Asp(87)Asn in GyrA, together with Ser(80)Ile, or Glu(84)Val in ParC. Majority of these isolates showed resistance to beta-lactams and multiresistance phenotype was found in 95% isolates. Forty-eight different sequence types among 144 isolates analyzed were found, including five major clones ST131 (26), ST355 (19), ST48 (13), ST95 (10), and ST10 (5). No isolates sharing 100% relatedness and originating from different areas were identified. In conclusion, our study identified PMQR genes in E. coli isolates in all areas studied, including highly virulent multiresistant clones such as ST131 producing CTX-M-15 beta-lactamases.

Highlights

Escherichia coli is a common part of the gastrointestinal flora of humans and animals but some strains can cause serious diseases
A collection of 1050 isolates of E. coli with reduced susceptibility or resistance to ciprofloxacin was obtained from humans, food producing, or wild animals and wastewater samples from the area of the Olomouc and South Moravian Regions, Czech Republic (Table 1)
The second most common gene was aac(6′)Ib-cr found in 82% of human plasmid-mediated quinolone resistance (PMQR)-positive clinical isolates followed by qnrB19 that dominated in isolates from turkey and wastewater samples

Summary

Introduction

Escherichia coli is a common part of the gastrointestinal flora of humans and animals but some strains can cause serious diseases. Quinolones are the antimicrobial agents of choice for treatment of various infections caused by E. coli or other Gramnegative bacteria. Because of extensive use for multiple clinical indications in human or veterinary medicine, bacterial resistance to quinolones has developed over the time (Andriole, 2005). According to the European Antimicrobial Resistance Surveillance Network (EARS-Net), an interactive database, an alarming emergence of fluoroquinolone-resistant invasive E. coli isolates is evident in European countries (European Centre for Disease Prevention and Control, 2015). Quinolone antibiotics are one of the most widely used antimicrobial agents in the treatment of urinary tract infections. The extensive use has led to the increase of the rate of E. coli isolates resistant to fluoroquinolones all over the world (Lautenbach et al, 2004; Dalhoff, 2012). E. coli isolates resistant to fluoroquinolones has been described in food-producing and companion animals (Platell et al, 2011; Gosling et al, 2012; Literak et al, 2013; Agabou et al, 2016) as well as in wild animals and the environment (Jiménez Gómez et al, 2004; Colomer-Lluch et al, 2013)

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