Open AccessPlasmid-encoded AmpC β-lactamases: how far have we gone 10 years after the discovery?
Author(s) -
A. Bauernfeind,
Yunsop Chong,
Kyungwon Lee
Publication year - 1998
Publication title -
yonsei medical journal/yonsei medical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.702
H-Index - 63
eISSN - 1976-2437
pISSN - 0513-5796
DOI - 10.3349/ymj.1998.39.6.520
Subject(s) - citrobacter freundii , plasmid , biology , gene , genetics , horizontal gene transfer , mobile genetic elements , computational biology , microbiology and biotechnology , genome , enterobacteriaceae , escherichia coli
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.