Open AccessImipenem resistance in Enterobacter aerogenes is associated with derepression of chromosomal cephalosporinases and impaired permeability
Author(s) -
Tzouvelekis L.S.,
Tzelepi E.,
Mentis A.F.,
Vatopoulos A.C.,
Tsakris A.
Publication year - 1992
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1992.tb05365.x
Subject(s) - imipenem , cephaloridine , derepression , enterobacter aerogenes , mutant , microbiology and biotechnology , carbenicillin , chemistry , overproduction , plasmid , biology , gene , biochemistry , antibiotic resistance , ampicillin , cephalosporin , antibiotics , gene expression , escherichia coli , psychological repression
Enterobacter aerogenes mutants with high‐level resistance to imipenem were studied. They were derived from strains characterized by stable overproduction of a class‐I β‐lactamase. This enzyme (p I = 8.2) exhibited high affinity toward imipenem and hydrolysed the drug slowly. Imipenem‐resistant mutants lacked a major 43‐kDa outer membrane protein and displayed decreased permeability to cephaloridine. Introduction of a plasmid coding for the regulatory ampD gene abolished β‐lactamase production and rendered the mutants susceptible to imipenem.