Infections in organ transplant recipients.

Since the introduction and widespread performance of transplant surgery in the 1950s and 1960s, infectious complications have been a major cause of morbidity and mortality. The risks of infection are directly related to the potency and duration of immunosuppressive therapies, organ-donor selection, surgical techniques, and postoperative exposures to invasive procedures or treatments. Despite impressive advancements to decrease the risks of infection, between 40% and 80% of renal transplant patients become infected within the first two or three postoperative years. Infections that occur during the first month following transplantation are often caused by common nosocomial pathogens and are secondary to invasive procedures or therapies. Infections that occur between one and six months postsurgery are often caused by opportunistic pathogens. Symptomatic and subclinical cytomegalovirus (CMV) infections are common during this time and may contribute to a further impairment of host defenses. Late infections involve both opportunistic and conventional pathogens; opportunistic infections occur in patients with poor transplant function who require high levels of immunosuppression and conventional infections occur in patients who require little immunosuppression. During the past two decades, there has been a significant decrease in deaths from infectious complications among renal transplant recipients. Further reductions in morbidity and mortality will occur with the development of more specific approaches for immunosuppressive therapy, new strategies to prevent CMV infections and methods to eliminate sources of nosocomial infections.