Fungal infections in the transplant recipient and laboratory methods for diagnosis.

Although the last twenty five years have produced tremendous technological advances in solid organ and bone marrow transplantation, a continuing problem for the transplant recipient is infection, with fungi playing a significant role. Risk of fungal infection varies with time following transplantation. The period of intense immuno-suppression between the first and sixth months following solid organ transplantation is notable for infections caused by opportunistic fungi such as Candida spp. and Aspergillus spp. [1]. These pathogens continue to threaten the solid organ recipient in later phases if organ rejection occurs. In the early phase following bone marrow trans-plantation (BMT) the risk of infection is determined by the duration of neutropenia and, as in other neutropenic populations, infections with Candida spp. are common [2]. The next phase, which follows marrow engraftment and typically includes the second and third post-transplant months, is dominated by fungal as well as viral pathogens. If neutropenia has been prolonged, the risk for infection with opportunistic fungal pathogens such as Aspergillus spp. rises dramatically [3]. In addition to the immunosuppresive therapy inherent to transplantation, other predisposing factors to inva-sive fungal infection in the hospitalized patient such as broad spectrum antibiotics, long-term venous access lines, hyperalimentation, malnutrition, disruption of mucosal and skin surfaces, and recent major surgical procedures [4,5] certainly apply to many transplant recipients. The incidence of invasive fungal infection ranges from 5% in kidney recipients [6] to greater than 20% in liver [5,7] and pancreas recipients [8]. Candida spp. are the most common fungal pathogens among the transplant population and in kidney and heart transplant recipients the manifestations of infection include esophagitis, urinary tract infection, and line-related infections [9]. Dissemination from these sites may subsequently occur. The renal transplant patient, in whom the urinary tract is a more common site of infection than in the other organ recipients, is prone to urinary tract infection with Candida spp. with the associated complications of obstruction due to the formation of fungus balls, and candidemia [10]. Colonization of the respiratory tract by Candida is usually innocuous, even in the transplant recipient. An exception to this is in the lung or heart/lung recipient, in whom involvement of the bronchial mucosa can have the devastating complications of rupture of the surgical anastomosis or fungal mediastinitis [11]. Liver transplant patients are at particularly high risk for infection with Candida, which at times accounts for 30% or more of all infections [5]. In one …