Dendrogram of pulsed-field gel electrophoresis (PFGE) profiles from 36 Escherichia coli isolates from 18 pups originating from kennel B. A: Isolate origin. B-a, B-b, B-c, B-d, and B-e litters consisted of two (B-a-1 to B-a-2), four (B-b-1 to B-b-4), five (B-c-1 to B-c-5), three (B-d-1 to B-d-3), and four pups (B-e-1 to B-e-4), respectively. Two isolates were obtained per pup. B: Resistance pattern. AMP, ampicillin; CFZ, cefazolin; CEF, ceftiofur; DHS, dihydrostreptomycin; GEN, gentamicin; OTC, oxytetracycline; CHL, chloramphenicol; SXT, trimethoprim-sulfamethoxazole; NAL, nalidixic acid; ENR, enrofloxacin. C: PFGE profile. Five isolates with the B-2 PFGE profile harboured the SHV-12 ESBL-encoding gene.