Characterisation of antibiotic resistance ofSalmonellaisolated from dog treats in Japan

Dog treats might be contaminated with Salmonella. In Canada and the USA, outbreaks of human salmonellosis related to exposure to animal-derived dog treats were reported. Consequently, surveillance data on Salmonella contamination of dog treats have been gathered in many countries, but not in Japan. In the current study, we investigated whether dog treats in Japan were contaminated with Salmonella. Overall, 303 dog treats (of which 255 were domestically produced) were randomly collected and the presence of Salmonella investigated. Seven samples were positive for Salmonella enterica subsp. enterica. Among these isolates, three were identified as serovar 4,5,12:i:-; two were serovar Rissen; and two were serovar Thompson. All serovar 4,5,12:i:- and Thompson isolates were resistant to one or more drugs. Two serovar Rissen isolates were fully susceptible to all tested antimicrobial agents. All Salmonella isolates were susceptible to cefotaxime, ciprofloxacin and nalidixic acid. The gene blaTEM was detected in two serovar 4,5,12:i:- isolates. The blaCTX-M and blaCMY genes were not detected in any isolates. This study demonstrated that dog treats in Japan could constitute a potential source of dog and human Salmonella infections, including multidrug-resistant Salmonella isolates.