Novel Complex sul1-Type Integron in Escherichia coli Carrying bla(CTX-M-9)

For the present report, a novel complex class 1 integron, In60, was characterized. Part of this integron includes the bla(CTX-M-9) gene and its downstream nucleotide sequence, which shares 81% and 78% nucleotide identity with those of kluA-1 β-lactamase and orf3 of K. ascorbata, respectively. Furthermore, a new insertion sequence, IS3000, has been found in In60. PCR analysis indicates that integron In60 is present in 33 of 34 nonclonal enterobacterial isolates carrying the putative β-lactamase CTX-M-9.