Resistant gram-positive organisms.

Antimicrobial resistance in Gram-positive bacteria has reemerged in the last decade as a major clinical problem. Methicillin-resistant staphylococci, penicillin-resistant pneumococci, and enterococci resistant to penicillin, vancomycin, and/or gentamicin have become new considerations in the selection of therapy. Both mutation and acquisition of new DNA on either the chromosome or plasmids can be responsible for resistance in Gram-positive species. Because therapies are often limited, renewed efforts are needed to understand the epidemiology in order to effect control.