BACKGROUND Invasive fungal infections, including candidemia, pose a major threat to patients with impaired immune defenses, including bone marrow transplantation (BMT) recipients. During 1992-1997, 845 women with multiple lymph node positive or metastatic breast carcinoma underwent high-dose chemotherapy (HDC) and subsequent autologous BMT at Duke University Medical Center. No systemic antifungal prophylaxis was administered. The purpose of the current study was to evaluate the risk and long-term outcome of candidemia in this patient population. METHODS Clinical data were collected on patients with candidemia, and a group of age-matched control patients were identified who underwent HDC and BMT for breast carcinoma in the same time period. The difference in crude mortality between these two groups was used to calculate the attributable mortality of candidemia. The genetic relatedness of the fungal blood stream isolates was investigated by DNA fingerprinting. Antifungal susceptibility testing was performed using serial microdilution. RESULTS Twenty-nine of 845 women developed candidemia (3.4%). The crude mortality of women with candidemia was 35% at 90 days after transplantation but 11% among women in the matched control group who were without infection (P = 0.01), for an attributable mortality rate of 24%. The most common pathogen was Candida tropicalis (50%), followed by Candida albicans (23%). The mortality was highest for women who were infected with C. albicans, followed by C. tropicalis, and other Candida species (P = 0.037). DNA fingerprinting of the yeasts revealed genetic heterogeneity in all species. However, 9 of 15 C. tropicalis isolates had identical DNA fingerprint profiles, suggesting spread of this genotype from a common source. All yeast isolates were susceptible to amphotericin B, and 20 of 30 isolates were susceptible to <or= 8 microg/mL of fluconazole. CONCLUSIONS Candidemia was relatively infrequent after HDC and autologous BMT in women with for multiple lymph node positive or metastatic breast carcinoma. This was true even in the absence of systemic antifungal prophylaxis. The mortality attributable to candidemia in this patient population was 24% and was higher among patients who were infected by C. albicans compared with patients who were infected by other Candida, non-albicans species.