First Isolation of bla VIM-2 in Klebsiella oxytoca Clinical Isolates from Portugal

VIM-type carbapenemases were originally detected in Europe (2, 4, 7) and have been essentially found in Pseudomonas aeruginosa, as well as in Enterobacteriaceae (2, 6, 8). The blaVIM genes are often carried by mobile gene cassettes inserted into class 1 integrons (7, 11). The Klebsiella genus is responsible for the most frequent human nosocomial infections of the respiratory and urinary tracts. Four Klebsiella oxytoca clinical isolates were recovered by blood culture from neonatal patients at a pediatric hospital. The clinical isolates showed resistance to amoxicillin and ticarcillin, which was restored by clavulanate, aminoglycosides, and fluoroquinolones, and intermediate susceptibility to imipenem (MIC, 4 μg/ml) and broad-spectrum cephalosporins and aztreonam (MICs, 8 and 16 μg/ml) and were susceptible to meropenem (MIC, 0.075 μg/ml). A deformation of ellipses between the two gradient sections with E-test MBL (metallo-β-lactamase) strips was indicative of MBL production (10).