Food Workers as a Reservoir of Extended-Spectrum-Cephalosporin-Resistant Strains in Japan.

Dissemination of extended-spectrum-cephalosporin (ESC)-resistant , especially extended-spectrum-β-lactamase (ESBL)-producing , is a concern worldwide. Here, we assessed carriage by food workers in Japan to clarify the prevalence of ESC-resistant harboring We then characterized the genetic features, such as transposable elements, of -harboring plasmids using whole-genome sequencing. A total of 145,220 stool samples were collected from food workers, including cooks and servers from several restaurants, as well as food factory workers, from January to October 2017. Isolated salmonellae were subjected to antimicrobial susceptibility testing (disk diffusion method), and whole-genome sequencing was performed for strains harboring Overall, 164 isolates (0.113%) were recovered from 164 samples, from which we estimated that at least 0.113% (95% confidence interval [CI]: 0.096 to 0.132%) of food workers may carry Based on this estimation, 3,473 (95% CI = 2,962 to 4,047) individuals among the 3,075,330 Japanese food workers are likely to carry Of the 158 culturable isolates, seven showed resistance to ESCs: three isolates harbored and produced AmpC β-lactamase, while four ESBL-producing isolates harbored ( = 1, serovar Senftenberg) or ( = 3, serovar Haardt). was chromosomally located in the Haardt isolates, which also contained IS, while the Senftenberg isolate contained an IncFIA(HI1)/IncHI1A/IncHI1B(R27) hybrid plasmid carrying along with IS This study indicates that food workers may be a reservoir of ESBL-producing and associated genes. Thus, these workers may contribute to the spread of via plasmids or mobile genetic elements such as IS Antimicrobial-resistant bacteria arise in farm environments through imprudent use of antimicrobials. Subsequently, these antimicrobial-resistant strains, such as extended-spectrum-β-lactamase (ESBL)-producing , may be transmitted to humans via food animal-derived products. Here, we examined carriage among food handlers in Japan. Overall, 164 of 145,220 fecal samples (0.113%) were positive for Among the 158 tested isolates, four were identified as ESBL-producing isolates carrying ESBL determinants or In all cases, the genes coexisted with IS, regardless of whether they were located on the chromosome or on a plasmid. Our findings suggest that food workers may be a reservoir of ESBL-producing strains and could contribute to the spread of resistance genes from farm-derived to other bacterial species present in the human gut.