Open AccessOxacillin‐hydrolyzing β‐lactamase involved in resistance to imipenem in Acinetobacter baumannii
Author(s) -
Hornstein M,
SautjeauRostoker C,
Péduzzi J,
Vessières A,
Han Hong Le Thi,
Barthélémy M,
Scavizzi M,
Labia R
Publication year - 1997
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.1574-6968.1997.tb12593.x
Subject(s) - imipenem , acinetobacter baumannii , microbiology and biotechnology , cephalosporin , acinetobacter , beta lactamase , chemistry , enzyme , carbapenem , antibiotics , bacteria , biology , antibiotic resistance , biochemistry , escherichia coli , genetics , gene , pseudomonas aeruginosa
Acinetobacter baumannii strain A148, a clinical isolate resistant to imipenem (MIC=32 mg l −1 ), synthesized two β‐lactamases with p I s 6.3 and >9.2. The p I 6.3 enzyme hydrolyzed the penicillins, including isoxazoylpenicillins, first‐, second‐ and, to a lesser extent, third‐generation cephalosporins. It was inhibited by chloride ions and by the penem β‐lactamase inhibitor BRL 42715. Clavulanate was a weak inhibitor and EDTA did not affect the β‐lactamase activity. This enzyme also hydrolyzed imipenem with a catalytic efficiency ( k cat / K m ) of 1500 mM −1 s −1 . Moreover, this purified β‐lactamase produced a positive microbiological clover‐leaf test with imipenem. Therefore, the p I 6.3 β‐lactamase was considered to be involved in the imipenem resistance of A. baumannii strain A148.