TEM-121, a novel complex mutant of TEM-type beta-lactamase from Enterobacter aerogenes.
Enterobacter aerogenes clinical isolate LOR was resistant to penicillins and ceftazidime but susceptible to cefuroxime, cephalothin, cefoxitin, cefotaxime, ceftriaxone, and cefepime. PCR and cloning experiments from this strain identified a novel TEM-type beta-lactamase (TEM-121) differing by five amino acid substitutions from beta-lactamase TEM-2 (Glu104Lys, Arg164Ser, Ala237Thr, Glu240Lys, and Arg244Ser) and by only one amino acid change from the extended-spectrum beta-lactamase (ESBL) TEM-24 (Arg244Ser), with the last substitution also being identified in the inhibitor-resistant beta-lactamase IRT-2. Kinetic parameters indicated that TEM-121 hydrolyzed ceftazidime and aztreonam (like TEM-24) and was inhibited weakly by clavulanic acid and strongly by tazobactam. Thus, TEM-121 is a novel complex mutant TEM beta-lactamase (CMT-4) combining the kinetic properties of an ESBL and an inhibitor-resistant TEM enzyme.
Poirel
Laurent
L
Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, Université Paris XI, Le Kremlin-Bicêtre, France.
Mammeri
Hedi
H
Nordmann
Patrice
P
D002442:Ceftazidime / Q000494:pharmacology*; D018550:Cephalosporin Resistance; D002511:Cephalosporins / Q000494:pharmacology*; D019818:Clavulanic Acid / Q000494:pharmacology; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000096:biosynthesis / Q000235:genetics; D021902:Enterobacter aerogenes / Q000201:enzymology* / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007525:Isoelectric Focusing; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014169:Transformation, Bacterial; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism*
D002511:Cephalosporins; D004269:DNA, Bacterial; D004791:Enzyme Inhibitors; D019818:Clavulanic Acid; D002442:Ceftazidime; D001618:beta-Lactamases; C495216:beta-lactamase TEM-121, Enterobacter aerogenes