Characterization of Isolates Producing Extended Spectrum Beta-Lactamase SHV-Variants from the Food Chain in Germany.

Resistance of bacteria to 3 generation cephalosporins mediated by beta-lactamases (ESBL, pAmpC) is a public health concern. In this study, 1517 phenotypically cephalosporin-resistant were screened for the presence of genes. Respective genes were detected in 161 isolates. Majority (91%) were obtained from poultry production and meat. The SHV-12 beta-lactamase was the predominant variant ( = 155), while the remaining isolates exhibited SHV-2 ( = 4) or SHV-2a ( = 2). A subset of the isolates ( = 51) was further characterized by PCR, PFGE, or whole-genome sequencing and bioinformatics analysis. The SHV-12-producing isolates showed low phylogenetic relationships, and dissemination of the genes seemed to be mainly driven by horizontal gene transfer. In most of the isolates, was located on transferable IncX3 (43 kb) or IncI1 (100 kb) plasmids. On IncX3, was part of a Tn6 composite transposon located next to a Tn3 transposon, which harbored the fluoroquinolone resistance gene . On IncI1 plasmids, was located on an incomplete class 1 integron as part of a Tn21 transposon. In conclusion, SHV-12 is widely distributed in German poultry production and spreads via horizontal gene transfer. Consumers are at risk by handling raw poultry meat and should take care in appropriate kitchen hygiene.