Spill-Over from Public Health? First Detection of an OXA-48-Producing Escherichia coli in a German Pig Farm

Resistance to carbapenems is a severe threat to human health. These last resort antimicrobials are indispensable for the treatment of severe human infections with multidrug-resistant Gram-negative bacteria. In accordance with their increasing medical impact, carbapenemase-producing Enterobacteriaceae (CPE) might be disseminated from colonized humans to non-human reservoirs (i.e., environment, animals, food). In Germany, the occurrence of CPE in livestock and food has been systematically monitored since 2016. In the 2019 monitoring, an OXA-48-producing E. coli (19-AB01443) was recovered from a fecal sample of a fattening pig. Phenotypic resistance was confirmed by broth microdilution and further characterized by PFGE, conjugation, and combined short-/long-read whole genome sequencing. This is the first detection of this resistance determinant in samples from German meat production. Molecular characterization and whole-genome sequencing revealed that the bla_OXA-48 gene was located on a common pOXA-48 plasmid-prototype. This plasmid-type seems to be globally distributed among various bacterial species, but it was frequently associated with clinical Klebsiella spp. isolates. Currently, the route of introduction of this plasmid/isolate combination into the German pig production is unknown. We speculate that due to its strong correlation with human isolates a transmission from humans to livestock has occurred.