New developments in the diagnosis and management of invasive fungal infections

Abstract

Invasive fungal infections in cancer patients are on the increase. Candidemia is now the fourth leading cause of bloodstream infections in many intensive care units (ICUs). Although a number of risk factors have been identified, antifungal therapy should not be started in non-neutropenic patients until a diagnosis of invasive candidiasis or candidemia is made or presumed in order to avoid the development of resistance. Even a single positive blood culture should be treated, and requires removal of intravascular lines. Fluconazole is the first line agent for treatment candidemia other than that caused by Candida glabrata or C. krusei. High-resolution CT scan pictures showing a halo sign or crescent air sign are helpful for establishing the diagnosis of invasive aspergillosis. Sandwich ELISA can be used to detect circulating galactomannan in serial serum samples. Polymerase chain reaction (PCR) of blood samples may also be used. There are only a few randomized studies of newly developed antifungal drugs compared to conventional amphotericin B (AmB). So far, both AmB colloidal dispersion and AmB lipid complex have failed to show more favorable efficacy or lesser toxicity rates, except for nephrotoxicity. Liposomal AmB, used during febrile neutropenia, did have a significantly lower toxicity rate. In neutropenic patients with invasive fungal infections liposomal AmB proved to be better than conventional AmB in terms of clinical efficacy, mortality and nephrotoxicity rates. The use of tests to achieve an earlier diagnosis combined with more potent treatment formulations such as liposomal AmB may be significant steps towards successful management of invasive fungal infections.