Identification of a blaVIM-4 gene in the internationally successful Klebsiella pneumoniae ST11 clone and in a Klebsiella oxytoca strain in Hungary

Sir, The VIM-type metallo-β-lactamases (MBLs) have been detected worldwide in Pseudomonas aeruginosa and Acinetobacter spp., and, more recently, in many species of Enterobacteriaceae. After the first detection of VIM-4 in P. aeruginosa in Greece in 2001,1 these strains were isolated in many countries, including Hungary, where VIM-4- producing P. aeruginosa and Aeromonas hydrophila were reported.2,3 In Hungarian clinical microbiological laboratories, the screening for presumptive carbapenemase producers is performed according to Hungarian guidelines, which are based on the CLSI recommendations.4 The putative production of MBLs is tested by the modified Hodge test, and disc tests containing imipenem and/or ceftazidime either alone or combined with EDTA. In 2009, 5% of Klebsiella spp. (1.4% of Enterobacteriaceae) isolates from the BP1 centre and 4.76% of Klebsiella spp. (2.4% of Enterobacteriaceae) isolates from the BP2 centre were ertapenem-resistant non-carbapenemase producers. No imipenem or meropenem non-susceptible strains were isolated during this year. Based on screening and confirmatory tests, one carbapenem-susceptible Klebsiella pneumoniae strain (KP3686) isolated from bronchoalveolar lavage (BP1 centre, February 2009) and one carbapenem-susceptible Klebsiella oxytoca strain (KO5294/9) isolated from stool (BP2 centre, July 2009) proved to be MBL producers. The aim of our study was to characterize the first Hungarian MBL-producing K. pneumoniae KP3686 and K. oxytoca KO5294/9 isolates.