title: Diversity of chromosomal AmpC beta-lactamases from Enterobacter cloacae isolates in a Portuguese hospital.
abstract: 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 beta-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 beta-lactamases (Eclo1FF, Eclo6FF, Eclo9FF, Eclo10FF, Eclo11FF and Eclo15FF) shared 97-99% homology with the chromosomal AmpC beta-lactamase from E. cloacae P99 and 86-87% homology with those of two plasmid-mediated AmpC beta-lactamases, MIR-1 and ACT-1. This is the first report of chromosomal AmpC beta-lactamase production by E. cloacae isolates in a Portuguese hospital.
authors.affiliation: Faculty of Pharmacy, Av. Forças Armadas, 1619-049 Lisbon, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Conceição
authors.forename: Nuno
authors.initials: N
authors.lastname: Faria
authors.forename: Luís
authors.initials: L
authors.lastname: Lito
authors.forename: José
authors.initials: J
authors.lastname: Melo Cristino
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Salgado
authors.forename: Aida
authors.initials: A
authors.lastname: Duarte
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D018550:Cephalosporin Resistance; D002876:Chromosomes, Bacterial; D016972:Enterobacter cloacae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology; D014644:Genetic Variation; D005838:Genotype; D006786:Hospitals, Urban; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D014169:Transformation, Bacterial; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D047090:beta-Lactams; C048795:AmpC beta-lactamases; D001618:beta-Lactamases