Worldwide Diversity of Klebsiella pneumoniae That Produces β-Lactamase blaKPC-2 Gene

Klebsiella pneumoniae isolates that produce carbapenemases (KPCs) are rapidly disseminating worldwide. To determine their genetic background, we investigated 16 bla(KPC-2)-harboring K. pneumoniae isolates from 5 countries. The isolates were multidrug resistant, possessed the bla(KPC-2) gene, and differed by additional beta-lactamase content. They harbored a naturally chromosome-encoded bla gene (bla(SHV-1) [12.5%], bla(SHV-11) [68.7%], or bla(OKP-A/B) [18.8%]) and several acquired and plasmid-encoded genes (bla(TEM-1) [81.3%], bla(CTX-M-2) [31.3%], bla(CTX-M-12) [12.5%], bla(CTX-M-15) [18.7%], and bla(OXA-9) [37.5%]). The bla(KPC-2) gene was always associated with 1 of the Tn4401 isoforms (a, b, or c). Tn4401 was inserted on different-sized plasmids that belonged to different incompatibility groups. Several bla(KPC)-containing K. pneumoniae clones were found: 9 different pulsotypes with 1 major (sequence type 258) and 7 minor distinct allelic profiles. Different clones harboring different plasmids but having identical genetic structure, Tn4401, could be at the origin of the worldwide spread of this emerging resistance gene.