title: Virulence and antimicrobial resistance determinants of verotoxigenic Escherichia coli (VTEC) and of multidrug-resistant E. coli from foods of animal origin illegally imported to the EU by flight passengers.
abstract: The aim of this study was to reveal phenotype/genotype characteristics of verotoxigenic Escherichia coli (VTEC) and multidrug resistant E. coli in food products of animal origin confiscated as illegal import at Austrian, German and Slovenian airports. VTEC isolates were obtained by using ISO guidelines 16654:2001 for O157 VTEC or ISO/ TS13136:2012 for non-O157 VTEC, with additional use of the RIDASCREEN® Verotoxin immunoassay. The testing of 1526 samples resulted in 15 VTEC isolates (1.0%) primarily isolated from hard cheese from Turkey and Balkan countries. Genotyping for virulence by using a miniaturized microarray identified a wide range of virulence determinants. One VTEC isolate (O26:H46) possessing intimin (eae) and all other essential genes of Locus of Enterocyte Effacement (LEE) was designated as enterohemorrhagic E. coli (EHEC). None of the other VTEC strains belonged to serogroups O157, O145, O111, O104 or O103. VTEC strains harbored either stx(1) (variants stx1(a) or stx(1c)) or st(x2) (variants stx(2a), stx(2b), stx(2a/d) or stx(2c/d)) genes. Pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) demonstrated high genetic diversity and identified three new sequence types (STs): 4505, 4506 and 4507. Food samples collected from the Vienna airport were also tested for E. coli quantities using the ISO 16649:2001, and for detection of multidrug resistant phenotypes and genotypes. The resulting 113 commensal E. coli isolates were first tested in a pre-screening against 6 selected antimicrobials to demonstrate multidrug resistance. The resulting 14 multidrug resistant (MDR) E. coli isolates, representing 0.9% of the samples, were subjected to further resistance phenotyping and to microarray analyses targeting genetic markers of antimicrobial resistance and virulence. Genotyping revealed various combinations of resistance determinants as well as the presence of class 1, class 2 integrons. The isolates harbored 6 to 11 antibiotic resistance genes as well as 1 to 14 virulence genes. In this panel of 14 MDR E. coli two strains proved to carry CTX-M type ESBLs, and one single isolate was identified as enteropathogenic E. coli (EPEC). In general, isolates carrying a high number of resistance determinants had lower number of virulence genes and vice versa. In conclusion, this first pilot study on the prevalence of VTEC and of MDR/ESBL E. coli in illegally imported food products of animal origin suggests that these strains could represent reservoirs for dissemination of potentially new types of pathogenic and MDR E. coli in Europe.
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary. Electronic address: bnagy@vmri.hu.
authors.forename: B
authors.initials: B
authors.lastname: Nagy
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: A
authors.initials: A
authors.lastname: Szmolka
authors.affiliation: Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: S
authors.initials: S
authors.lastname: Smole Možina
authors.affiliation: Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: J
authors.initials: J
authors.lastname: Kovač
authors.affiliation: University of Veterinary Medicine Vienna, Institute for Milk Hygiene, Milk Technology and Food Science, Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Strauss
authors.affiliation: AGES, Institute for Medical Microbiology and Hygiene, Graz, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Schlager
authors.affiliation: Federal Institute for Risk Assessment, Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Beutlich
authors.affiliation: Federal Institute for Risk Assessment, Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Appel
authors.affiliation: National Laboratory of Health, Environment and Food, Center for Microbiologic Analysis of Food, Water and other Environmental Samples Maribor, Slovenia.
authors.forename: M
authors.initials: M
authors.lastname: Lušicky
authors.affiliation: ID Genomics, Seattle, WA, USA.
authors.forename: P
authors.initials: P
authors.lastname: Aprikian
authors.affiliation: National Center for Epidemiology, Budapest, Hungary.
authors.forename: J
authors.initials: J
authors.lastname: Pászti
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: I
authors.initials: I
authors.lastname: Tóth
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: R
authors.initials: R
authors.lastname: Kugler
authors.affiliation: University of Veterinary Medicine Vienna, Institute for Milk Hygiene, Milk Technology and Food Science, Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Wagner
mesh_terms: D059028:Airports; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D002611:Cheese / Q000382:microbiology*; D018432:Drug Resistance, Multiple; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000235:genetics; D005060:Europe; D005838:Genotype; D058885:Multilocus Sequence Typing; D022603:Shiga Toxins / Q000235:genetics; D054323:Shiga-Toxigenic Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity*; D014195:Travel; D014421:Turkey; D014774:Virulence / Q000235:genetics*
chemical_list: D000890:Anti-Infective Agents; D029968:Escherichia coli Proteins; D022603:Shiga Toxins
keywords: ESBL; Illegally imported food; MLST; Multidrug resistance; Stx; VTEC