High rates of metallo-beta-lactamase-producing Klebsiella pneumoniae in Greece - a review of the current evidence

For the last four years Greece has faced a large number of infections, mainly in the intensive care units (ICU), due to carbapenem-resistant, VIM-1-producing Klebsiella pneumoniae. The proportion of imipenem-resistant K. pneumoniae has increased from less than 1% in 2001, to 20% in isolates from hospital wards and to 50% in isolates from ICUs in 2006. Likewise, in 2002, these strains were identified in only three hospitals, whereas now they are isolated in at least 25 of the 40 hospitals participating in the Greek Surveillance System. This situation seems to be due to the spread of the blaVIM-1 cassette among the rapidly evolving multiresistant plasmids and multiresistant or even panresistant strains of mainly K. pneumoniae and also other enterobacterial species. However, the exact biological basis of this phenomenon and the risk factors that facilitate it are not yet fully understood. Moreover, the fact that most strains display minimum inhibitory concentration (MIC) values below or near the Clinical Laboratory Standard Institute (CLSI) resistance breakpoint create diagnostic and therapeutic problems, and possibly obstruct the assessment of the real incidence of these strains.