Six clinical isolates of Enterobacter cloacae isolated in a Portuguese hospital, between April 1999 and November 2000, demonstrated resistance to almost all broad-spectrum cephalosporins, except to cefepime. These isolates were susceptible to quinolones and to aminoglycosides. Isoelectric focusing demonstrated production of β-lactamases with pIs>8.0 and by all six isolates, exhibiting a cephalosporinase phenotype. The results of pulsed field gel electrophoresis revealed that these isolates were genetically unrelated. The amino acid sequence of six AmpC β-lactamases (Eclo1FF, Eclo6FF, Eclo9FF, Eclo10FF, Eclo11FF and Eclo15FF) shared 97-99% homology with the chromosomal AmpC β-lactamase from E. cloacae P99 and 86-87% homology with those of two plasmid-mediated AmpC β-lactamases, MIR-1 and ACT-1. This is the first report of chromosomal AmpC β-lactamase production by E. cloacae isolates in a Portuguese hospital. © 2003 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.
Conceição, T., Faria, N., Lito, L., Cristino, J. M., Salgado, M. J., & Duarte, A. (2004). Diversity of chromosomal AmpC β-lactamases from Enterobacter cloacae isolates in a Portuguese hospital. FEMS Microbiology Letters, 230(2), 197–202. https://doi.org/10.1016/S0378-1097(03)00891-7