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Recent Developments in β-Lactamase Research and Their Implications for the Future
Reviews of Infectious Diseases
Vol. 10, No. 4, New Developments in Resistance to β-Lactam Antibiotics among Nonfastidious Gram-Negative Organisms (Jul. - Aug., 1988), pp. 681-690
Published by: Oxford University Press
Stable URL: http://www.jstor.org/stable/4454537
Page Count: 10
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β-Lactamases, major determinants of bacterial resistance to β-lactam antibiotics, can be classified into specific molecular classes following identification of active-site amino acid or nucleotide sequences. The use of gene probes for epidemiologic purposes is becoming commoner. A semiempirical classification scheme has been proposed using substrate profiles and inhibition by clavulanic acid and aztreonam as criteria. Class 1 cephalosporinases are potently inhibited by aztreonam but poorly inhibited by clavulanate, whereas class 2 penicillinases and broad-spectrum β-lactamases have very poor affinities for aztreonam but are inhibited by clavulanic acid. Class 3 β-lactamases include the metallo-enzymes. Resistance to β-lactam antibiotics can be related to many β-lactamase-mediated phenomena, including increased frequency of β-lactamase production in clinical isolates, wider distribution of β-lactamase-mediating plasmids, production of multiple β-lactamases, induction of chromosomal class 1 cephalosporinases, selection of derepressed mutants for production of class 1 enzymes, leakage of β-lactamase from gram-negative organisms, functions of penicillin-binding proteins as β-lactamases, and identification of novel β-lactamases.
Reviews of Infectious Diseases © 1988 Oxford University Press