Prevalence and molecular features of ESBL/pAmpC-producing Enterobacteriaceae in healthy and diseased companion animals in Brazil

Extended-spectrum beta-lactamase (ESBL)-and plasmid-mediated AmpC (pAmpC)-carrying Enterobacteriaceae have widely disseminated in human, animal and environmental reservoirs. Pets have been recognized as a source of ESBL/pAmpC worldwide, and are possibly also a source of human contamination. The aim of this study was to document to what extent cats and dogs may act as a driving force in the spread of ESBLs and pAmpCs in Brazil. A total of 113 healthy stray cats and dogs and 74 sick pets were sampled, and extended-spectrum cephalosporinresistant Enterobacteriaceae (ESC-R) were detected in 28/113 (24.8%) and 8/74 (10.8%) tested animals, respectively. Different Enterobacteriaceae isolates (mostly E. coli), a large number of E. coli clones (with ST90, ST457, ST973 and ST2541 being predominant), and several ESBL/pAmpC genes and plasmids were characterized, highlighting the ability of stray and pet cats and dogs to further spread a wide range of ESC-resistance determinants. The ESBL phenotype was due to the bla(CTX-M-2) and bla(CTX-M-8) genes, as found in human epidemiology in Brazil, but bla(CTX.M.9) and bla(CTX-M-15) were also identified. The pAmpC phenotype was systematically due to the presence of the bla(CMY-2) gene, mostly carried by Incl1 ST12 plasmids. Our results showed that pets can be considered a significant reservoir of multidrug-resistant bacteria in Brazil. This is especially true for healthy stray dogs that displayed the highest prevalence (24.8%) of ESBLs/pAmpC resistance determinants, which can then be further spread both to the environment and to other animals or humans by contact. (AU)