Extended-spectrum-β-lactamase-producing Enterobacteriaceae isolated from vegetables imported from the Dominican Republic, India, Thailand, and Vietnam.
To examine to what extent fresh vegetables imported into Switzerland represent carriers of extended-spectrum-β-lactamase (ESBL)-producing Enterobacteriaceae, 169 samples of different types of fresh vegetables imported into Switzerland from the Dominican Republic, India, Thailand, and Vietnam were analyzed. Overall, 25.4% of the vegetable samples yielded one or more ESBL-producing Enterobacteriaceae, 78.3% of which were multidrug resistant. Sixty isolates were obtained: Escherichia coli, 26; Klebsiella pneumoniae, 26; Enterobacter cloacae, 6; Enterobacter aerogenes, 1; and Cronobacter sakazakii, 1. We found 29 isolates producing CTX-M-15, 8 producing CTX-M-14, 7 producing CTX-M-55, 3 producing CTX-M-65, 1 each producing CTX-M-1, CTX-M-3, CTX-M-27, and CTX-M-63, 5 producing SHV-2, 3 producing SHV-12, and 1 producing SHV-2a. Four of the E. coli isolates belonged to epidemiologically important clones: CTX-M-15-producing B2:ST131 (1 isolate), D:ST405 (1 isolate), and D:ST38 (2 isolates). One of the D:ST38 isolates belonged to the extraintestinal enteroaggregative E. coli (EAEC) D:ST38 lineage. Two of the K. pneumoniae isolates belonged to the epidemic clones sequence type 15 (ST15) and ST147. The occurrence of antibiotic-resistant pathogenic and commensal Enterobacteriaceae in imported agricultural foodstuffs constitutes a source of ESBL genes and a concern for food safety.
Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Zurich, Switzerland.
Katrin
K
Zurfluh
Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Zurich, Switzerland.
Magdalena
M
Nüesch-Inderbinen
Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Zurich, Switzerland.
Marina
M
Morach
Cantonal Office of Consumer Protection Aargau, Aarau, Switzerland.
Annina
A
Zihler Berner
Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Zurich, Switzerland.
Herbert
H
Hächler
Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Zurich, Switzerland stephanr@fsafety.uzh.ch.
Roger
R
Stephan
D001208:Asia; D004293:Dominican Republic; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D005838:Genotype; D058889:Molecular Typing; D013557:Switzerland; D014675:Vegetables / Q000382:microbiology*; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D001618:beta-Lactamases