Fungal and bacterial infections in the immunocompromised host

As the number of immunocompromised patients increases due to the spread of the AIDS epidemic and the successes being achieved with transplantation, cancer chemotherapy and immunosuppressive therapy, increased attention is being turned to the prevention and treatment of the infections that afflict these individuals. The risk of infection in these patients is determined by the interaction between the epidemiologic exposures that the patient experiences and the net state of immunosuppression (the greater the exposure, the greater the chances of infection even in an immunologically competent individual; the greater the net state of immunosuppression, the greater the chances of infection even with minimal exposures). The bacterial and fungal infections that affect these patients are reviewed and strategies of antimicrobial management defined, recognizing that there are three modes of use of antimicrobial agents in these patients: therapeutic administration to treat clinical infection, and prophylactic and pre-emptive administration to prevent or abort clinical infection. These last two are of particular importance in this patient population because the prime aim of the infectious disease clinician in dealing with these problems is the prevention of clinical disease.