Chromosome-encoded CTX-M-3 from Kluyvera ascorbata:: a possible origin of plasmid-borne CTX-M-1-derived cefotaximases

A gene identical to plasmid-borne bla(CTX-M-3) is present in the chromosome of one Kluyvera ascorbata strain. It is associated with a structure including an inverted repeat right and an open reading frame 477-like gene probably involved in the mobilization of bla(CTX-M-3). Two other K. ascorbata strains rendered the previously described bla(KLUA-9) gene.