Emergence and nosocomial spread of ST11 carbapenem-resistant Klebsiella pneumoniae co-producing OXA-48 and KPC-2 in a regional hospital in Taiwan

Abstract

<b>Purpose.</b> Carbapenem-resistant <i>Klebsiella pneumoniae</i> (CRKP) has emerged as a major challenge for global healthcare systems. The objectives of this study were to determine the nosocomial spread of CRKP clones and analyse the molecular characteristics of CRKP in our hospital.<b>Methodology.</b> Ninety-eight non-duplicated clinical CRKP isolates were collected from March 2014-June 2015. Clinical, demographic and microbiological data of patients with CRKP were reviewed. Pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing were applied to investigate the genetic relationship between the 98 isolates. Antibiotic resistance genes were identified by conventional PCR-sequencing.<b>Results.</b> PFGE patterns were grouped into 26 clusters. Two main PFGE clusters were identified: L (53 isolates, belonging to ST11) and N (11 isolates, belonging to ST11). The most dominant ST was ST11 (79 %, 77/98), followed by ST273 (5 %, 5/98). KPC-2 (<i>n</i>=82) was the predominant carbapenemase followed by OXA-48 (<i>n</i>=64). Fifty isolates (51 %, 50/98) harboured <i>bla</i> _KPC-2 and <i>bla</i> _OXA-48 simultaneously, and three of these isolates were detected with the third carbapenemase genes (<i>bla</i> _IMP-8 or <i>bla</i> _VIM-1).<b>Conclusion.</b> The clonal spread of <i>K. pneumoniae</i> ST11 expressing OXA-48, KPC-2 and CTX-M-14 β-lactamases was the cause of an outbreak of CRKP. To the best of our knowledge, a single strain harbouring A-, B- and D-class carbapenemase genes has not previously been identified. There is a high prevalence of plasmid-encoded KPC-2- and OXA-48-producing CRKP in our hospital; most isolates were members of ST11, which may be representative of a high-risk CRKP clone disseminating in central Taiwan.