Emergence and mechanisms of bacterial resistance in surgical infections.

Antimicrobial resistance is commonplace among bacteria involved in surgical infections, including Staphylococcus aureus, enterococci, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and Bacteroides species. Resistance traits can be encoded on chromosomes or transmissible plasmids. The basic mechanisms of resistance are alteration of drug target, prevention of drug access to target, and drug inactivation. Examples include alteration of penicillin-binding proteins in resistance to penicillinase-resistant penicillins, ribosomal binding site protection in tetracycline resistance, and beta-lactamase destruction of beta-lactam compounds. Resistance due to the many types of beta-lactamases that have thus far been identified is wide-spread among common pathogens; use of beta-lactam/beta-lactamase inhibitor combinations has proved effective as one means of counteracting such resistance. Contending with resistance involves appropriate use of available antimicrobials, development of novel agents or modification of existing agents, and measures to forestall emergence and spread of resistant organisms.