Antibacterial activity of β-lactam antibiotics against extended- spectrum β-lactamase producing bacteria

Akio Kuga, Hisakazu Yano, Ryoichi Okamoto, Yuko Sato, Aiko Miyata, Matsuhisa Inoue

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    2 Citations (Scopus)


    MICs of various β-lactam antibiotics by themselves and in combination with β-lactamase inhibitor (clavulanic acid) against extended spectrum β- lactamase (ESBL) producing strains of Escherichia coli and Klebsiella pneumoniae which were isolated from clinical materials were investigated. Furthermore, based on the results obtained, a procedure to detect ESBL producing strains was proposed. The MICs of β-lactam antibiotics against β- lactamase producing strains were investigated. At first, β-lactamase was investigated by the drug sensitivity pattern (MIC) to β-lactam antibiotics and by the substrate profiles of β-lactamase extracted from the transconjugant of E. coli K-12 strains. After that, we classified the β- lactamase producing gene by PCR method. Furthermore, a proposal was made for an antibiotic to be used in the confirmation of mixed type β-lactamase. The data obtained by the above investigations were compiled and used to determine the limit concentration of each β-lactam against β-lactamase producing strains including ESBL. By using β-lactam antibiotics at the following concentrations, it is considered possible to classify β-lactamase; ampicillin (64 μg/ml), ampicillin/clavulanic acid (32/5 μg/ml), piperacillin (64 μg/ml), cefotaxime (1 μg/ml), cefpodoxime (2 μg/ml), ceftazidime (1 μg/ml), cefmetazole (4 μg/ml), cefminox (2 μg/ml), cefepime (0.5 μg/ml), aztreonam (1 μg/ml) and imipeneme (1 μg/ml). This method may be used as a reference in investigating the prevalence of β-lactam resistant isolates by ESBL producing E. coli and K. pneumoniae.

    Original languageEnglish
    Pages (from-to)585-594
    Number of pages10
    JournalJapanese Journal of Antibiotics
    Issue number9
    Publication statusPublished - 1999 Sep 1

    ASJC Scopus subject areas

    • Microbiology (medical)
    • Pharmacology (medical)
    • Infectious Diseases


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