Genetic context of and genes in a foodborne serotype Saintpaul isolate from China.

resistant to fluoroquinolones (FQs) and extended-spectrum cephalosporins (ESCs) has been deemed a high-priority pathogen by the WHO. serovar Saintpaul (. Saintpaul) co-resistant to ESCs and FQs and harboring corresponding resistance genes ( and ) have been previously reported. However, they have not been reported in China. Moreover, the genetic context and transferability of ESCs and FQs resistance genes in . Saintpaul remain obscure. This study is the first study to characterize a multidrug-resistant (MDR) . Saintpaul isolate (16Sal016) harboring plasmid-mediated and genes recovered from weever fish in China. The whole genome short- and long-read sequencing results identified the presence of 15 acquired antibiotic resistance genes encoding resistance to nine classes of antibiotics, as well as abundant mobile genetic elements residing on a 259,529 bp IncHI2 plasmid. The and genes were located in a 12,865 bp region, IS---IS-IS-Tn-- -IS--IS. Similar structures have been identified in various bacterial species, indicating a high transferability of and genes within this gene cluster. The plasmid was found to be transferable to () J53 by conjugation and resulted in the acquisition of multiple resistances by the transconjugants. Genome sequence comparisons by core genome multilocus sequence typing (cgMLST) based on global 2,947 . Saintpaul isolates indicated that strain 16Sal016 was epidemiologically linked with an isolate from the United Kingdom (UK). Our findings suggest that plasmids and IS-mediated mobile genetic elements are carriers of and genes in . Saintpaul, and highlight their potential transmission, which needs continuous investigations.