Inhibitor-resistant TEM (IRT) beta-lactamases with different substitutions at position 244.
A novel inhibitor-resistant TEM (IRT) beta-lactamase was detected in an Escherichia coli isolate resistant to amoxicillin-clavulanate and susceptible to cephalothin. The substrate and inhibitor profiles of this beta-lactamase were similar to those of IRT-1 and IRT-2. The novel IRT's bla gene was sequenced, and the deduced amino acid sequence showed the amino acid replacement Arg for His-244 of the TEM-1 sequence. Substitutions for Arg-244 have been reported in three TEM-1 mutants: IRT-1 (which corresponds to TEM-31) (Cys), IRT-2/TEM-30 (Ser), and TEM-41 (Thr). We designated this novel beta-lactamase, which corresponds to TEM-51, IRT-15.
Bret
L
L
Laboratoire de Bactériologie, Faculté de Médecine, Clermont-Ferrand, France.
Chaibi
E B
EB
Chanal-Claris
C
C
Sirot
D
D
Labia
R
R
Sirot
J
J
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D008826:Microbial Sensitivity Tests; D013329:Structure-Activity Relationship; D001618:beta-Lactamases / Q000737:chemistry* / Q000187:drug effects; D047090:beta-Lactams
D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1