Open AccessA New TEM-Derived Extended-Spectrum β-Lactamase (TEM-91) with an R164C Substitution at the Ω-Loop Confers Ceftazidime Resistance
Author(s) -
Hiroshi Kurokawa,
Naohiro Shibata,
Yohei Doi,
Keigo Shibayama,
Kazunari Kamachi,
Tetsuya Yagi,
Yoshichika Arakawa
Publication year - 2003
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.47.9.2981-2983.2003
Subject(s) - ceftazidime , isoelectric point , clavulanic acid , escherichia coli , cefotaxime , microbiology and biotechnology , biology , chemistry , chromatography , bacteria , antibiotics , amoxicillin , biochemistry , enzyme , gene , genetics , pseudomonas aeruginosa
A new plasmid-mediated TEM-derived extended-spectrum beta-lactamase, TEM-91, was identified in a ceftazidime-resistant (MIC, >128 microg per ml) Escherichia coli strain isolated in 1996 in Japan. TEM-91 has three amino acid substitutions, R164C, M184T, and E240K, compared with TEM-1 penicillinase. The isoelectric point (pI), K(m), and k(cat) of TEM-91 for ceftazidime were 5.7, 179 microM, and 29.0 s(-1), respectively. The K(i) of clavulanic acid for ceftazidime hydrolysis was 30.3 nM.