Open AccessBiochemical and genetic characteristics of TEM‐29B, a novel extended spectrum β‐lactamase
Author(s) -
Bou G,
Martı́nezBeltrán J,
Cerveró G,
PérezDı́az J.C
Publication year - 1999
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.1574-6968.1999.tb13567.x
Subject(s) - ceftazidime , aztreonam , cefotaxime , clavulanic acid , escherichia coli , microbiology and biotechnology , plasmid , beta lactamase , strain (injury) , enterobacteriaceae , biology , chemistry , gene , bacteria , antibiotics , amoxicillin , genetics , anatomy , pseudomonas aeruginosa
A clinical strain of Escherichia coli (strain Ec 41553) that was resistant to ceftazidime produced a TEM‐type β‐lactamase with a p I of 5.4. Clavulanic acid restored the ceftazidime activity, thus suggesting an extended spectrum β‐lactamase (ESBL). The gene encoding ESBL was located in a plasmid of 57 kb. After cloning and sequencing, the ESBL (TEM‐29B) showed one amino acid replacement with respect to the TEM‐1 sequence, Arg‐164 to His. This change increased mainly the rate of hydrolysis of ceftazidime but not of cefotaxime and aztreonam. The relevance of this substitution in the increase of ceftazidime MIC is thus stressed.