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. 2005 Aug;43(8):4163-7.
doi: 10.1128/JCM.43.8.4163-4167.2005.

Inhibitor-based methods for detection of plasmid-mediated AmpC beta-lactamases in Klebsiella spp., Escherichia coli, and Proteus mirabilis

Philip E Coudron  1
Affiliations

Inhibitor-based methods for detection of plasmid-mediated AmpC beta-lactamases in Klebsiella spp., Escherichia coli, and Proteus mirabilis

Philip E Coudron. J Clin Microbiol. 2005 Aug.

Abstract

Non-beta-lactam inhibitor-based methods were evaluated for detecting plasmid-mediated AmpC beta-lactamases in Klebsiella spp., Escherichia coli, and Proteus mirabilis. Using CLSI methodology and disks containing cefotetan alone and in combination with 400 mug of boronic acid, 9 of 10 positive control strains and 54 of 55 AmpC-PCR-positive clinical isolates were detected. Importantly 71% and 40% of these clinical isolates were susceptible by routine testing to ceftriaxone and ceftazidime, respectively. Boronic acid disks also enhanced detection of expanded-spectrum beta-lactamases in AmpC producers.

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Figures

FIG. 1.
FIG. 1.
Comparison of the standard confirmatory disk test for ESBL and the boronic acid (bor) disk test for AmpC β-lactamase with two K. pneumoniae control strains. Strain ATCC 700603 produced ESBL and no AmpC β-lactamase, and strain R154 produced AmpC β-lactamase and no ESBL. CAZ, ceftazidime; CAZ CLAV, ceftazidime and clavulanic acid; CTT, cefotetan; CTT + bor, cefotetan and 400 μg of boronic acid.
FIG. 2.
FIG. 2.
Comparison of the confirmatory ESBL test using the standard ceftazidime and ceftazidime/clavulanic disks and the same two disks, each with a second disk, containing 400 μg of boronic acid (bor), placed on top. The K. pneumoniae isolate harbored both an ESBL and an AmpC β-lactamase.
See this image and copyright information in PMC

References

    1. Bauernfeind, A., I. Schneider, R. Jungwirth, H. Sahly, and U. Ullmann. 1999. A novel type of AmpC β-lactamase, ACC-1, produced by a Klebsiella pneumoniae strain causing nosocomial pneumonia. Antimicrob. Agents Chemother. 43:1924-1931. - PMC - PubMed
    1. Bradford, P. A., C. Urban, N. Mariano, S. J. Projan, J. J. Rahal, and K. Bush. 1997. Imipenem resistance in Klebsiella pneumoniae is associated with the combination of ACT-1, a plasmid-mediated AmpC β-lactamase, and the loss of an outer membrane protein. Antimicrob. Agents Chemother. 41:563-569. - PMC - PubMed
    1. Caroff, N., E. Espaze, D. Gautreau, H. Richet, and A. Reynaud. 2000. Analysis of the effects of -42 and -32 ampC promoter mutations in clinical isolates of Escherichia coli hyperproducing AmpC. J. Antimicrob. Chemother. 45:783-788. - PubMed
    1. Clinical and Laboratory Standards Institute. 2005. Performance standards for antimicrobial susceptibility testing: 15th informational supplement. M100-S15. Clinical and Laboratory Standards Institute, Wayne. Pa.
    1. Coudron, P. E., E. S. Moland, and K. S. Thomson. 2000. Occurrence and detection of AmpC beta-lactamases among Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis isolates at a veteran's medical center. J. Clin. Microbiol. 38:1791-1796. - PMC - PubMed

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