Worldwide diversity of Klebsiella pneumoniae that produce beta-lactamase blaKPC-2 gene

Abstract

Klebsiella pneumoniaeisolates that produce carbapenemases (KPCs) are rapidly disseminating worldwide. To determine their genetic background, we investigated 16 blaKPC-2-harboring K. pneumoniae isolates from 5 countries. The isolates were multidrug resistant, possessed the blaKPC-2 gene, and differed by additional Beta-lactamase content. They harbored a naturally chromosome-encoded bla gene (blaSHV-1 [12.5%], blaSHV-11 [68.7%], or blaOKP-AVB [18.8%]) and several acquired and plasmid-encoded genes (blaTEM-1 [81.3%], blaCTX-M-2 [31.3%], blaCTX-M-12 [12.5%], blaCTX-M-15 [18.7%], and blaOXA-9 [37.5%]). The blaKPC-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 blaKPC-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.

Figure 1

A) Schematic representation of Tn4401 isoforms on plamids of Klebsiella pneumoniae isolates that produce K. pneumoniae carbapenemases (KPCs). Genes and their corresponding transcription orientations are indicated by horizontal arrows. Gray triangles represent the inverted repeats left (IRL) and right (IRR) of Tn4401. Small and empty triangles represent the inverted repeats of ISKpn6 and ISKpn7. Target site duplications (TSD) are indicated above the sequence. Primers listed in Table 2 are shown below, with results of PCRs for each isolate. B) PCR results with primers 7 and 8 (Table 2). Lane 1, K. pneumoniae YC (11); lane 2, K. pneumoniae GR (21); lane 3, K. pneumoniae K271 (25); lane 4, K. pneumoniae KN2303 (13); lane 5, K. pneumoniae KN633 (13); lane 6, K. pneumoniae INC H1521-6; lane 7, K. pneumoniae INC H1516-6; lane 8, K. pneumoniae HPTU 27635; lane 9, K. pneumoniae HPTU 2020532; lane 10, K. pneumoniae A28006 (16); lane 11, K. pneumoniae A28008 (16); lane 12, K. pneumoniae A28009 (16); lane 13, K. pneumoniae A28011 (16); lane 14, K. pneumoniae A33504 (16); lane 15, K. pneumoniae 475; lane 16, K. pneumoniae 588.

Figure 2

A) Plasmid extractions of culture of clinical Klebsiella pneumoniae isolates that produce β-lactamase bla_KPC-2 gene. B) Southern hybridization of transferred plasmid extraction, conducted with an internal probe for bla_KPC-2. Lane 1, K. pneumoniae YC (11); lane 2, K. pneumoniae GR (21); lane 3, K. pneumoniae K271 (25); lane 4, K. pneumoniae KN2303 (13); lane 5, K. pneumoniae KN633 (13); lane 6, K. pneumoniae INC H1521-6; lane 7, K. pneumoniae INC H1516-6; lane 8, K. pneumoniae HPTU 27635; lane 9, K. pneumoniae HPTU 2020532; lane 10, K. pneumoniae A28006 (16); lane 11, K. pneumoniae A28008 (16); lane 12, K. pneumoniae A28009 (16); lane 13, K. pneumoniae A28011 (16); lane 14, K. pneumoniae A33504 (16); lane 15, K. pneumoniae 475; lane 16, K. pneumoniae 588; and lane 17, Escherichia coli 50192 harboring 4 plasmids (7, 48, 66, and 154 kb).