Emerging Fungal Pathogens: Evolving Challenges to Immunocompromised Patients

Abstract

Fungal pathogens are emerging as important causes of morbidity and mortality in immunocompromised patients. Among the well-known life-threatening and deeply invasive fungi are Candida albicans (the most common cause of disseminated nosocomial fungal infection), Aspergillus fumigatus (the most common cause of nosocomial fungal pneumonia), and Cryptococcus neoformans (the most common cause of central nervous system [CNS] mycosis in human immunodeficiency virus [HIV]-infected patients). Fusarium spp. are representative of the emerging group of hyaline molds, which cause respiratory and disseminated infections in immunocompromised patients. The dematiaceous molds represent a diverse group of fungal pathogens which share the presence of melanin-like pigments in the cell wall. Infections due to azole-resistant C. albicans and non-albicans Candida species, heretofore rare events, have become commonplace. During the past decade, substantial advances have been achieved in understanding of the pathogenesis, detection, and treatment of infections with this emerging pathogen. Such approaches may provide a model for understanding other emerging fungal pathogens. The infection presents with numerous necrotic lesions, which are papulonodular lesions that may simulate those of tuberculosis, leishmaniasis, cryptococcosis, or histoplasmosis in HIV-infected patients. This infection in severely immunocompromised patients with disseminated penicilliosis has been successfully managed with amphotericin B. For mild to moderate disease, there is increasing experience with therapeutic success with itraconazole. The fungal pathogens that have emerged during the past decade have developed in an expanding population of immunocompromised hosts, new antifungal selective pressures, and shifting environmental conditions.