Rising incidence of Candida parapsilosis fungemia in patients with hematologic malignancies: clinical aspects, predisposing factors, and differential pathogenicity of the causative strains.

Over the years 1983-1994, Candida parapsilosis causes 35 or 138 fungemic episodes (24 of 69 candidemias in the last quadriennium) in patients with hematologic malignancies who were being treated at a large university hospital in Italy. The central venous catheter was usually the source of bloodstream invasion; in most cases, the resolution of fungemia in patients receiving antifungal therapy required catheter removal. In seven cases, C. parapsilosis fungemia evolved to five proven (two cases with endocarditis) and two probable deep-seated infections; three of these seven patients died of deep-seated infections. Deep seated infection was associated with the detection of a circulating mannoprotein antigen of C. parapsilosis but not with in vitro resistance to antifungal agents. Almost all fungal isolates produced slime in vitro, but only 34% were pathogenic in a model of bloodstream infection in neutropenic mice. The four isolates associated with endocarditis or persistent fungemia with multiorgan failure were among the most virulent in the model of infection. Overall, our findings highlight the role of C. parapsilosis as an agent of fungemia in patients with malignant hemopathies.