Interspecies spread of CTX-M-32 extended-spectrum β-lactamase and the role of the insertion sequence IS1 in down-regulating blaCTX-M gene expression

Abstract

Data suggest putative in vivo horizontal bla(CTX-M-32) gene transfer between two different genera of Enterobacteriaceae. A new complex structure, IS5-IS1, was detected upstream of the bla gene and IS1 negatively modulated expression of the bla(CTX-M-32) gene because its location modified the bla promoter region.