A new TEM-derived extended-spectrum β-lactamase (TEM-91) with an R164C substitution at the ω-loop confers ceftazidime resistance

Hiroshi Kurokawa, Naohiro Shibata, Yohei Doi, Keigo Shibayama, Kazunari Kamachi, Tetsuya Yagi, Yoshichika Arakawa

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A new plasmid-mediated TEM-derived extended-spectrum β-lactamase, TEM-91, was identified in a ceftazidime-resistant (MIC, >128 μg 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), Km, and kcat of TEM-91 for ceftazidime were 5.7, 179 μM, and 29.0 s-1, respectively. The Ki of clavulanic acid for ceftazidime hydrolysis was 30.3 nM.

Original languageEnglish
Pages (from-to)2981-2983
Number of pages3
JournalAntimicrobial agents and chemotherapy
Issue number9
Publication statusPublished - 01-09-2003
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Pharmacology (medical)
  • Infectious Diseases

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