The aadB gene cassette is associated with bla(SHv) genes in Klebsiellaspecies producing extended-spectrum beta-lactamases

Integrons were detected in 37 (72.5%) of 51 Klebsiella spp. producing extended-spectrum beta-lactamases by PCR with primers that targeted integrase genes and cassette regions. PCR and amplicon sequencing of the cassette regions revealed aadB and aadA2 gene cassettes that confer resistance to a range of aminoglycosides. aadB was associated with a class I integron on a 28-kb plasmid, pES1, that also contained bla(SHV-12) and IS26.