The incidence of beta-lactamase-producing pathogens.

In addition to the bacteria which naturally are able to enzymatically inactive penicillins and/or cephalosporins, a large number of species may develop this ability through mutation, acquisition of plasmids, or insertion of transposons. Characterization of the beta-lactamase activity of various pathogens has shown that a wide variety of enzymes exists and that new ones continue to evolve. The distribution of the genes for the numerous beta-lactamases vary according to geographic location and pathogen. Recently beta-lactamase inhibitors (sulbactam and clavulanic acid) have become available which, in combination with different beta-lactam antibiotics, expand the activity of those hydrolyzable antibiotics to pathogens producing beta-lactamases. The epidemiology of resistant pathogens and of the beta-lactamase genes that make them resistant are important factors in evaluating the role of these beta-lactam/beta-lactamase inhibitor combinations.