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Clin Infect Dis. 2001 Apr 1;32(7):1085-9. Epub 2001 Mar 21.

New beta-lactamases in gram-negative bacteria: diversity and impact on the selection of antimicrobial therapy.

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The R. W. Johnson Pharmaceutical Research Institute, Raritan, NJ, 08869, USA.


Of the 340 discrete beta-lactamases that have been identified, the most important groups of enzymes that are continuing to proliferate include the plasmid-encoded cephalosporinases, the metallo-beta-lactamases, and the extended-spectrum beta-lactamases. Resistance to specific beta-lactam-containing antimicrobial agents frequently can be traced to a single beta-lactamase, but this task is becoming more difficult for the clinical microbiology laboratory. Other factors, such as multiple beta-lactamase production, transferable multidrug-resistance genes, alterations in outer-membrane porins, and possible antibiotic efflux, all may contribute to a resistance phenotype. Appreciation of these factors may help the physician make a more informed decision when choosing therapy to try to avoid selection of even more pathogenic strains.

[Indexed for MEDLINE]

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