title: Plasmid-encoded AmpC beta-lactamases: how far have we gone 10 years after the discovery?
abstract: The dogma that ampC genes are located exclusively on the chromosome was dominant until about 10 years ago. Since 1989 over 15 different plasmid-encoded AmpC beta-lactamases have been reported from several countries. Most of these enzymes evolved in two clusters. The major cluster includes several enzymes with a high similarity to CMY-2, which is the closest related chromosomal AmpC enzyme of Citrobacter freundii. A second cluster centers around CMY-1. It is less homogeneous and not closely related chromosomal AmpC enzymes. Molecular diversification by amino acid substitutions does not usually translate into a change in the resistance phenotype. At this time, CMY-2 appears to be the most prevalent and widely distributed. Further global increase of prevalence and diversity of plasmidic AmpC beta-lactamases have to be anticipated in the next millenium.
authors: Max von Pettenkofer Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universitat München, Germany. Adolf.Bauernfeind@mvp-bak.med.uni-muenchen.de
authors: A
authors: A
authors: Bauernfeind
authors: Y
authors: Y
authors: Chong
authors: K
authors: K
authors: Lee
mesh_terms: D001426:Bacterial Proteins; D008829:Microbiology / Q000639:trends; D010957:Plasmids / Q000235:genetics*; D013329:Structure-Activity Relationship; D014018:Tissue Distribution; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases