Molecular epidemiology of VIM-1 producing Klebsiella pneumoniae isolates

Abstract number: 1733_168

Kraniotaki E., Platsouka E., Belesiotou E., Nepka M., Psaroudaki Z., Argyropoulou A., Paniara O.

Objectives: This study was performed to investigate the molecular epidemiology of MBL producing blood isolates of Klebsiella pneumoniae, collected in our tertiary care hospital in the two-year period 2005–2006.

Methods: All consecutive K. pneumoniae isolates from blood cultures of 140 inpatients (49 in medical wards, 17 in surgical wards, 74 in ICUs) were tested. They were identified by standard methods and MICs were determined by the broth microdilution method, according to CLSI guidelines. MBL production was screened by Etest MBL. blaVIM-1 alleles were detected by PCR. The clonality of the VIM-1 positive isolates was examined by PFGE, using the restriction enzyme XbaI.

Results: Seventy out of one hundred forty isolates were found to produce an MBL activity by the Etest. The MICs of imipenem(IMI)and meropenem (MER) of the above MBL(+) isolates ranged from 0.5 to ≥16 mg/mL. The same seventy isolates, 50% of the total K. pneumoniae blood isolates, were found positive for the presence of the blaVIM-1 gene. PFGE results revealed four distinct genotypes among the MBL(+)isolates.

Conclusion: The presence of the blaVIM-1 gene in 50% of our K. pneumoniae blood isolates is high. The fact that four distinct genotypes were involved in the nosocomial spread of the MBL resistance, indicates horizontal transfer of the blaVIM-1 gene. Continuous surveillance and control measures, comprising molecular investigation methods, are necessary in order to eliminate the MBLs.