Phenotypic and genotypic antimicrobial resistance and virulence genes of <i>Salmonella enterica</i> isolated from pet dogs and cats

Phenotypic and genotypic antimicrobial resistance and virulence genes of <i>Salmonella enterica</i> isolated from pet dogs and cats

<i>Salmonella enterica</i> isolates (n = 122), including 32 serotypes from 113 dogs and 9 cats, were obtained from household dogs (n = 250) and cats (n = 50) during 2012？2015. The isolates were characterized by serotyping, antimicrobial resistance phenotyping and genotyping, and virulence gene screening. Serovars Weltevreden (15.6%) and Typhimurium (13.9%) were the most common. The majority (43%) of the isolates were multidrug resistant. The dog isolates (12.3%) harbored class 1 integrons, of which the <i>dfrA12</i>-<i>aadA2</i> cassette was most frequent (66.7%). The only class integron in serovar Albany was located on a conjugative plasmid. Two ESBL-producing isolates (<i>i.e</i>., a serovar Krefeld and a serovar Enteritridis) carried <i>bla</i>_TEM and <i>bla</i>_CTX-M, and the <em>bla</em>_TEM gene in both was horizontally transferred. Of the plasmid-mediated quinolone resistance genes tested, only <i>qnrS</i> (4.9%) was detected. Most <i>Salmonella</i> isolates harbored <i>invA</i> (100%), <i>prgH</i> (91.8%), and <i>sipB</i> (91%). Positive associations between resistance and virulence genes were observed for <i>bla</i>_PSE-1/<i>orgA</i>, <i>cmlA</i>/<i>span</i>, <i>tolC</i>, and <i>sul1</i>/<i>tolC</i> (<i>p</i> ＜ 0.05). The results suggest that companion dogs and cats are potential sources of <i>S. enterica </i>strains that carry resistance and virulence genes and that antimicrobial use in companion animals may select for the examined <i>Salmonella</i> virulence factors.