A ten-year surveillance study of carbapenemase-producing Klebsiella pneumoniae in a tertiary care Greek university hospital: predominance of KPC- over VIM- or NDM-producing isolates

Resistance patterns and carbapenemase gene presence among Klebsiella pneumoniae isolates from the University General Hospital of Patras, Greece during a ten-year period were analysed under a surveillance programme for multi-drug-resistant bacteria. From 2005 to 2014, K pneumoniae isolates from clinically significant specimens were identified by the Vitek 2 Advanced Expert System. Antibiotic susceptibility testing was performed by the agar disc diffusion method and Etest. The strains were tested for the presence of bla(VIM), bla(IMP), bla(KPC) bla(NDM) and bla(OXA-48) genes by PCR. PFGE of chromosomal Xbal DNA digests was performed. A total of 3449 K pneumoniae isolates were recovered during the last decade. Among them, 1668 (48 %) were carbapenemase-producing: 1333 (80 %) K pneumoniae carbapenemase (KPC)-, 286 (17 %) Verona imipenemase (VIM), 45 (3 %) KPC- and VIM-, and four New Delhi metallo-beta-lactamase (NDM)-producing. Their resistance rates to gentamicin, colistin and tigecycline were 41 %, 23 % and 16 %, respectively. VIM-producing K pneumoniae were isolated in 2005 and since 2008 have been endemic. KPC-producing K pneumoniae (KPC-Kp) isolates were introduced in 2008 and until now represent the predominant carbapenemase-producing K pneumoniae in our institution. PFGE of 97 KPC-Kp strains identified three types: A, 84 (87 %); B, 11 (11 %); and E, two (2 %). Eleven co-producing KPC and VIM K. pneumoniae isolates belonged to PFGE B. The four NDM-positives were classified to type F. The number of K. pneumoniae bacteraemias increased during the study period, which may be solely attributed to the increase of carbapenemase-producing isolates. The threat of carbapenemase-producing K pneumoniae emphasizes the urgent need for implementation of infection control measures and budgetary allocations to infection control.