Systemic mycoses: the changing spectrum in contemporary medicine

ABSTRACT

The last twenty years have witnessed a dramatic increase in the incidence of systemic fungal infections throughout the world. While acquired immunodeficiency syndrome [AIDS] has emerged as a single most important risk factor for endemic mycoses, a variety of iatrogenic and other factors continue to predispose a significant proportion of immunosuppressed patients to infection with fungal pathogens. Amongst the endemic mycoses, histoplasmosis has become an important opportunistic infection largely in mid-west, coccidioidomycosis in south-west and blastomycosis in south-central of the USA. In southeast Asia, penicilliosis due to Penicillium marneffei has emerged as a major endemic mycosis of AIDS patients. Opportunistic yeast infections have become more common than infections caused by filamentous fungi, occupying fourth position in the list of bloodstream pathogens in some centers. Also, their incidence, pattern of clinical presentation and species spectrum has significantly altered, largely due to more frequent and prolonged use of antifungal drugs and subsequent development of resistance. Consequently, infections with less susceptible yeast species such as Candida lusitaniae, C, krusei, C. tropicalis, C. glabrata, and Trichosporon beigelii have been reported with greater frequency. The problem of antifungal resistance is likely to expand in future as more and more patients with AIDS, bone marrow transplant, and neutropenia will need chemoprophylaxis cover. Amongst other fungal infections, aspergillosis has emerged as an important disease in bone marrow transplant recipients, cryptococcosis and penumocystosis in patients with AIDS, fusariosis in leukemics receiving cytotoxic therapy, zygomycosis in diabetics and in haemodialysis patients on deferoxamine therapy and Malassezia furfur infection in patients receiving intravenous lipid emulsions. Never before in the history of medicine, opportunistic systemic mycoses were so important as they are today. The factors contributing to the rising incidence of these life-threatening infections are unlikely to recede; rapidly expanding population of AIDS patients in Africa and Asia is just one example. Under this rapidly changing scenario, the need to create a greater awareness about their epidemiology, diagnosis and therapy is imperative