Bench-to-bedside review: Candida infections in the intensive care unit

Fungi have emerged worldwide as an increasingly frequent cause of opportunistic infections. A survey of the epidemiology of sepsis conducted in the USA [1] revealed that the incidence of fungal sepsis increased threefold between 1979 and 2000. In contrast, numerous studies have revealed either no increase or sometimes even a decrease in the incidence of Candida sepsis [2-4]. Candida and Aspergillus spp. are the most frequent causes of invasive fungal infections and are associated with high morbidity and mortality [3,5,6]. The incidence of invasive candidiasis is sevenfold to 15-fold higher than that of invasive aspergillosis [3]. Originally described in immunocompromised hosts, primarily cancer patients, opportunistic fungal pathogens have now been recognized as a frequent cause of infection in surgical and critically ill patients.The epidemiology of invasive mold infections is changing. Invasive aspergillosis is now also occurring in intensive care unit (ICU) patients, including mechanically ventilated patients and patients with chronic lung diseases treated with corticosteroids [7]. Moreover, the number of strains of non-fumigatus Aspergillus spp. is on the rise and multi-resistant non-Aspergillus mould infections are emerging. Although these are undoubtedly important epidemiological changes, this review article focuses on recent advances in our understanding of the epidemiology, diagnosis and treatment of invasive candidiasis, which is the predominant fungal infection occurring in critically ill patients.Candida is now the fourth leading micro-organism responsible for bloodstream infections in the USA, outnumbering all Gram-negative bacilli [8-10]. Data from 790 ICUs reporting to the US National Nosocomial Infection Surveillance system between 1990 and 1999 [8,11] showed that Candida spp. were responsible for 5% to 10% of all bloodstream infections.Studies of Candida infections in Europe have revealed significant differences from recent trends observed in the USA