ESBL/AmpC-producing Enterobacteriaceae in imported food products

To assess the importance of global food products as a transmission route and vehicle for ESBL/AmpC/carbapenemase-producing Enterobacteriaceae, we sampled 200 food products purchased from Finland capitol region during fall 2018. Food products originated from 35 different countries from six different continents and two Great Oceans and represented four different food categories: vegetables (n=60), fruits and berries (n=50), meat (n=60), and seafood products (n=30). Additionally, subsamples (n=40) were taken from raw broiler meat. Raw, ready-to-eat, frozen and cooked products were included. Samples were screened for ESBL/AmpC-producing Enterobacteriaceae by cultivating on MacConkey agar supplemented with third-generation cephalosporin. Species identification was carried out with MALDI-TOF mass spectrometry, antimicrobial susceptibility testing with disc diffusion method, and whole genome sequencing was used to identify resistance and virulence genes, sequence types and plasmid replicons. Altogether, 14 out of 200 (7%) samples were positive for ESBL/AmpC-producing Escherichia coli and/or Klebsiella pneumoniae. No carbapenemase producing Enterobacteriaceae were found. Most of the positive samples were recovered from meat samples (18%; 11 out of 60) and three (5%; 3 out of 60) from vegetable samples. ESBL/AmpC-producing Enterobacteriaceae were not found in seafood or fruit samples. Subsampling of raw broiler meat revealed ESBL/AmpC-producing E. coli and K. pneumoniae in 90% (36 out of 40) of subsamples. Whole genome sequencing of selected isolates (n=21) revealed a wide collection of different ST types, plasmid replicons and genes conferring multidrug resistance (MDR) in all sequenced samples.