Hazardous Crossing: Immunosuppression and Nosocomial Infections in Solid Organ Transplant Recipients

BACKGROUND: During the past decade, ever-increasing numbers of patients have undergone renal, pancreatic, small bowel, hepatic, cardiac, or lung transplantation as therapy for various types of renal disease requiring dialytic therapy. Indications for solid organ transplantation include type I and, rarely, type II diabetes mellitus; hyperalimentation-dependent short gut syndrome; and formerly fatal liver, cardiac, or pulmonary failure. Significant improvements in patient and allograft survival have been observed in all categories. Unfortunately, despite such improved results, the risks of infection related to immunosuppression continue to be substantial. METHODS: Review of pertinent studies from the English literature. RESULTS: Suppression of host defenses by exogenous immunosuppressive agents renders patients susceptible to invasion by either resident or environmental bacterial, fungal, viral, and protozoal microbes or parasites. In such patients, invasion of organisms that produce mild infection in nonimmunosuppressed individuals can produce severe, lethal disease. Moreover, even low-virulence microbes may invade, proliferate, and cause disease in the immunosuppressed host; such organisms are referred to as "opportunistic" pathogens when they cause disease under these conditions. CONCLUSION: Advances in the field of transplantation have been substantial, particularly in the regulation of therapeutic immunosuppression, in prophylactic measures to prevent infection, and in more effective diagnosis and treatment modalities.