The changing epidemiology of fungal infections: are the lipid-based forms of amphotericin B an advance?

:  The incidence of invasive fungal infections is increasing and new fungal species are emerging as important pathogens. In cancer patients, the main risk factor for the development of systemic fungal disease is severe, prolonged neutropenia. Other factors, such as mucosal damage, presence of a central venous line, immunosuppressive therapy and treatment with broad spectrum antibiotics are contributory. Candida spp. are the fungi most commonly isolated in neutropenic patients. There has been a dramatic increase in non-C. albicans species, such as C. glabrata and C. krusei, largely as a result of extensive prophylactic and therapeutic use of fluconazole, to which these species are largely resistant. In neutropenic patients with candidaemia, amphotericin B is the drug of choice although the conventional formulation may be poorly tolerated. Lipid-based forms of amphotericin B, such as Abelcet®, are better tolerated and can be given at a much higher dose and should therefore be considered in patients who fail on or are intolerant to the conventional agent. Aspergillosis is the second most frequent fungal infection in neutropenic patients. Primary invasive aspergillosis usually presents on chest X-ray with lung lesions and the brain is a frequent site of secondary infection. Fluconazole is inactive against Aspergillus spp. and amphotericin B is the standard treatment. Again, lipid-based forms are better tolerated than the conventional formulation in this setting, and have been shown to achieve response rates of 60% or more in a number of trials. Other potentially life-threatening fungal infections in which lipid-based amphotericin B may play an important therapeutic role in the future include cryptococcosis (increasingly problematic in AIDS patients), trichosporonosis, fusariosis and mucormycosis. Further randomized studies should be performed in a range of fungal infections to compare Abelcet®with conventional amphotericin B and other lipid-based antifungal agents.