Surveillance and molecular epidemiology of Klebsiella pneumoniae isolates that produce carbapenemases: first report of OXA-48-like enzymes in North America.

A study was designed to characterize nonrepeat isolates of carbapenemase-producing K. pneumoniae obtained from the SMART worldwide surveillance program during 2008 and 2009. Characterization was done by PCR and sequencing for bla(VIM), bla(IMP), bla(NDM), bla(OXA), bla(KPC), and plasmid-mediated quinolone resistance and virulence factors (VFs). Genetic relatedness was determined with pulsed-field gel electrophoresis (PFGE) using XbaI and multilocus sequence typing. A total of 110 isolates were included; 47 possess genes that encode K. pneumoniae carbapenemases (KPCs), 26 NDMs, 19 VIMs, 13 OXA-48-like, and 5 imipenems (IMPs). We identified 3 different major sequence types (STs) among 65% of the isolates (i.e., ST11 [n = 11], ST147 [n = 23], and ST258 [n = 38]). ST11 and ST147, producing OXA-48-like and NDMs, were found in Argentina, Turkey, Greece, Italy, and India; ST258, producing KPCs, was present in the United States, Israel, Greece, and Puerto Rico. The major STs consisted of up to 4 different pulsotypes, and each pulsotype had a specific geographical distribution. A new ST, named ST903, with bla(IMP-26), was identified in the Philippines, while two bla(OXA-48)-positive isolates were detected in the United States. There were no significant differences in the distribution of the VFs between the isolates; all were positive for fimH, mrkD, wabG, and ureA. This is the first report of OXA-48-like enzymes in North America. Our study highlights the importance of surveillance programs using molecular techniques as powerful tools to identify the importance of international sequence types.