An update on antimicrobial chemotherapy: 2. The mechanisms of antibiotic resistance.

Healthcare workers worldwide are facing an unprecedented increase in the emergence and dissemination of antimicrobial-resistant micro-organisms. The current problem differs from those in the past because several different organisms are involved and there are no immediate solutions on the horizon. A topical example relates to strains of Staphylococcus aureus that are resistant to methicillin. These have become endemic in numerous hospitals and long-term care institutions, leaving vancomycin as the sole effective agent for many people infected with this organism. The resistance problem is not purely hospital-based and it is important for general practitioners to realize that community-acquired infections, such as meningitis caused by pneumococci, may also be caused by resistant organisms. This article will review some of the more common mechanisms of resistance.