A Wohlfahrtiimonas chitiniclastica with a novel type of bla(VEB–1)-carrying plasmid isolated from a zebra in China

BACKGROUND: Wohlfahrtiimonas chitiniclastica is an emerging fly-borne zoonotic pathogen, which causes infections in immunocompromised patients and some animals. Herein, we reported a W. chitiniclastica BM-Y from a dead zebra in China. METHODS: The complete genome sequencing of BM-Y showed that this isolate carried one chromosome and one novel type of bla(VEB–1)-carrying plasmid. Detailed genetic dissection was applied to this plasmid to display the genetic environment of bla(VEB–1). RESULTS: Three novel insertion sequence (IS) elements, namely ISWoch1, ISWoch2, and ISWoch3, were found in this plasmid. aadB, aacA1, and gcuG were located downstream of bla(VEB–1), composing a gene cassette array bla(VEB–1)–aadB–aacA1–gcuG bracketed by an intact ISWoch1 and a truncated one, which was named the bla(VEB–1) region. The 5′-RACE experiments revealed that the transcription start site of the bla(VEB–1) region was located in the intact ISWoch1 and this IS provided a strong promoter for the bla(VEB–1) region. CONCLUSION: The spread of the bla(VEB–1)-carrying plasmid might enhance the ability of W. chitiniclastica to survive under drug selection pressure and aggravate the difficulty in treating infections caused by bla(VEB–1)-carrying W. chitiniclastica. To the best of our knowledge, this is the first report of the genetic characterization of a novel bla(VEB–1)-carrying plasmid with new ISs from W. chitiniclastica.