OBJECTIVES Both transposition and increases in gene expression have been implicated in the success of KPC-producing pathogens, but the stimulus required for these phenomena are unknown. It is possible that exposure to antimicrobials during patient treatment increases bla(KPC) expression or induces Tn4401 transposition. The purpose of this study was to determine if exposure to carbapenems or oth...

The carbapenemase gene bla(KPC), which is rapidly spreading worldwide, is located on a Tn3-based transposon, Tn4401. In a transposition-conjugation assay, Tn4401 was able to mobilize bla(KPC-2) gene at a frequency of 4.4 × 10(-6)/recipient cell. A 5-bp target site duplication was evidenced upon each insertion without target site specificity. This study demonstrated that Tn4401 is an active tran...