Overview of the epidemiological profile and laboratory detection of extended-spectrum beta-lactamases.
Clin Infect Dis 2006;
42 Suppl 4:S153-63. [PMID:
16544266 DOI:
10.1086/500662]
[Citation(s) in RCA: 138] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Extended-spectrum beta-lactamases (ESBLs) are plasmid-mediated bacterial enzymes that confer resistance to a broad range of beta-lactams. They are descended by genetic mutation from native beta-lactamases found in gram-negative bacteria, especially infectious strains of Escherichia coli and Klebsiella species. Genetic sequence modifications have broadened the substrate specificity of the enzymes to include third-generation cephalosporins, such as ceftazidime. Because ESBL-producing strains are resistant to a wide variety of commonly used antimicrobials, their proliferation poses a serious global health concern that has complicated treatment strategies for a growing number of hospitalized patients. Another resistance mechanism, also common to Enterobacteriaceae, results from the overproduction of chromosomal or plasmid-derived AmpC beta-lactamases. These organisms share an antimicrobial resistance pattern similar to that of ESBL-producing organisms, with the prominent exception that, unlike most ESBLs, AmpC enzymes are not inhibited by clavulanate and similar beta-lactamase inhibitors. Recent technological improvements in testing and in the development of uniform standards for both ESBL detection and confirmatory testing promise to make accurate identification of ESBL-producing organisms more accessible to clinical laboratories.
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