The approach to antibiotic use in elderly patients is a unique and challenging problem. Older patients often suffer more serious complications of infection. Approximately one third of persons older than age 80 and a higher percentage of elderly disabled persons reside in long-term care facilities; bacterial flora in such institutions remain intermediate between the relatively antibiotic-resistant hospital flora and the flora typical of community-acquired infections. The rapid emergence of resistant microorganisms and the development of new classes of antimicrobial agents present potential diagnostic dilemmas and therapeutic challenges to treating clinicians.

This article focuses on the special characteristics of infection in the elderly and provides an update of the principles of antibiotic selection, use of specific antibiotics, and empiric use of antimicrobials in the treatment of infectious diseases in this particularly vulnerable group. Antituberculous, antifungal, and antiviral agents are mentioned only briefly; detailed information regarding these classes of agents in reference to aging can be found in standard reviews of antimicrobial therapy in the elderly.