ABSTRACT
This chapter discusses general concepts about the exhibited resistance enzymes that have allowed them to propagate and evolve into formidable beta-lactam destroying adversaries, and suggests treatment options. Beta-lactamases are enzymes produced by the great majority of clinically important bacteria. In the case of the beta-lactamases, the enzyme orients the beta-lactam antibiotic in a precise manner in its active site to facilitate the breaking of the C–N bond in the four-membered beta-lactam ring. Beta-lactamases are encoded by genes, and so the genetic structure of the regions surrounding the beta-lactamase genes is of considerable interest. Information about the genetic environment can give clues to the likely mobility of the gene, the extent to which it may be expressed, and to its origins and evolution. Beta-lactamase-mediated resistance is often transferable between cells because the genes are encoded on transferable plasmids. These plasmids may encode many resistance phenotypes, and even several beta-lactamases.
