blaCTX-M-2 is located in an unusual class 1 integron (In35) which includes Orf513

Examination of the bla(CTX-M-2) gene in plasmid pMAR-12 by sequencing and PCR analysis revealed that the bla gene and the surrounding DNA, which is closely related (99% homology) to the Kluyvera ascorbata chromosomal DNA that contains the bla(KLUA-1) gene, are located in a complex sul1-type integron, termed 105, that includes Orf513. It is possible that blaCTX-M-2 was acquired by plasmid pMAR-12 through an uncharacterized recombinational event in which Orf513 could be involved.