Hospital epidemiologic surveillance for invasive aspergillosis: Patient demographics and the utility of antigen detection

OBJECTIVE: To monitor the epidemiology of invasive aspergillosis at a university hospital during a period of hospital construction. To compare the efficacy of active epidemiologic surveillance for invasive aspergillosis using Aspergillus cultures with the efficacy of surveillance using Aspergillus antigen detection. DESIGN: A prospective surveillance study. SETTING: An 850-bed, tertiary-care, university-based hospital. PATIENTS: A convenience sample of 153 patients with Aspergillus antigen testing and culture. RESULTS: 24 cases were identified over a 12-month period; 7 were nosocomial, and 17 were community-acquired. Cases occurred primarily in patients with hematologic malignancy, but also occurred in patients with solid tumor, steroid treatment, cardiac transplant, and acquired immunodeficiency syndrome. Culture techniques identified only 14 (58%) of 24 cases, whereas Aspergillus antigen was positive in 19 (79%) of 24 cases tested. Epidemiological surveillance using either antigen or culture positivity detected 22 (92%) of 24 cases. In addition, antigen detection was 98% specific for the detection of aspergillosis, as compared to 91% for culture and 88% for antigen and culture combined. CONCLUSIONS: Hospital surveillance for aspergillosis should include determination of whether cases are nosocomial or community-acquired, because many may be the latter. Patients at risk for aspergillosis include patients without hematologic malignancies. Enhanced case detection occurred with active surveillance of patients considered to be at risk using both fungal serology and traditional microbiological techniques. Antigen detection was more sensitive and specific for the detection of invasive aspergillosis and may improve epidemiological surveillance for aspergillosis.