Low Occurrence of Extended‐Spectrum β‐lactamase‐Producing Escherichia coli in Finnish Food‐Producing Animals

Summary ESBL/AmpC‐producing Escherichia coli is increasingly isolated from humans and animals worldwide. The occurrence of ESBL/AmpC‐producing E. coli was studied in food‐producing animals in Finland, a country with a low and controlled use of antimicrobials in meat production chain. A total of 648 cattle, 531 pig, 495 broiler and 35 turkey faecal samples were collected from four Finnish slaughterhouses to determine the presence of extended‐spectrum β‐lactamase (ESBL/AmpC)‐producing E. coli . In addition, 260 broiler and 15 turkey samples were screened for carbapenemase‐producing E. coli . Susceptibility to different class of cephalosporins and meropenem was determined with disc diffusion tests according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Determination of ESBL/AmpC production was performed with a combination disc diffusion test according to the recommendations of the European Food Safety Authority (EFSA). Plasmidic  bla ESBL/AmpC  genes were characterized by polymerase chain reaction and sequencing. A collection of isolates producing AmpC enzyme but not carrying plasmidic  bla AmpC  was analysed by PCR and sequencing for possible chromosomal ampC promoter area mutations. Altogether ESBL/AmpC‐producing  E. coli  was recovered from five cattle (0.8%), eight pig (1.5%) and 40 broiler samples (8.1%). No ESBL/AmpC‐producing  E. coli  was found in turkey samples. Carbapenem resistance was not detected. Altogether ESBL/AmpC‐producing E. coli was found on 4 (2.0%), 3 (4.5%) and 14 (25%) cattle, pig and broiler farms, respectively. From cattle samples 3 (27%) bla CTX‐M‐1  and from broiler samples 13 (33%) bla CTX‐M‐1  and 22 (55%) bla CMY‐2 gene‐carrying isolates were detected. In pigs, no plasmidic bla ESBL/AmpC gene‐carrying isolates were found. In all analysed isolates, the same mutations in the promoter region of chromosomal amp C were detected. The results showed low occurrence of ESBL/AmpC‐producing E. coli in Finnish food‐producing animals. In pigs, plasmidic bla ESBL/AmpC ‐carrying E. coli was not detected at all.