Objectives: To describe the molecular and population-level characterization of a selected group of OXA-48-like-producing Klebsiella pneumoniae isolates collected in Spain between January 2011 and May 2012.
Methods: During the study period, 151 OXA-48-like-producing K. pneumoniae isolates were collected from 10 hospitals in six different Spanish regions. From these, a representative sample of 21 isolates that caused hospital outbreaks and single infections was selected for further in-depth analysis. Molecular epidemiology was investigated using PFGE and multilocus sequence typing (MLST). Resistance genes were characterized by PCR and sequencing. Plasmids carrying bla(OXA-48-like) were studied by PFGE with S1 nuclease digestion.
Results: All 21 isolates had ertapenem MICs ≥ 1 mg/L, but 47.6% remained susceptible to imipenem and meropenem; bla(OXA-48) was identified in 19 isolates (90.5%) and the novel bla(OXA-244) and bla(OXA-245) genes were detected in 1 isolate each. With one exception, all isolates that contained bla(OXA-48-like) also contained bla(CTX-M-15). PFGE typing revealed six clusters comprising isolates that belonged to MLST types ST11, ST16, ST392, ST405, ST437 and ST663, respectively. Two main clusters were identified: PFGE cluster 1 (12 isolates, belonging either to ST405 or ST663, from seven hospitals), and PFGE cluster 2 (4 ST16 isolates from two hospitals). Six of seven donor isolates conjugated successfully; bla(OXA-48-like) (but not bla(CTX-M-15)) was carried on ≈ 60 kb Inc L/M plasmids.
Conclusions: Multidrug-resistant K. pneumoniae producing OXA-48-like carbapenemase are emerging as important pathogens in Spain due to intra- and inter-hospital, clonal and non-clonal dissemination.