The epidemiology of invasive pulmonary aspergillosis at a large teaching hospital

OBJECTIVE: To characterize the epidemiology of invasive pulmonary aspergill osis (IPA). DESIGN: A retrospective case series. SETTING: An 850-bed, academic. tertiary-care medical center. PARTICIPANTS: Adult inpatients, between January 1, 1990, and December 31, 1 998, with either a histopathology report consistent with IPA or a discharge diagnosis of aspergillosis. METHODS: We reviewed medical records and categorized case-patients as defin itive or probable and acquisition of IPA as nosocomial, indeterminate, or c ommunity using standard definitions. To determine the rate of aspergillus r espiratory colonization, we identified all inpatients who had a respiratory culture positive for Aspergillus species without a histopathology report c onsistent with IPA or a discharge diagnosis of aspergillosis. Three study i ntervals were defined: interval 1, 1990 to 1992; interval 2, 1993 to 1995; and interval 3, 1996 to 1998. Carpeting in rooms for patients following hea rt-lung and liver transplant was removed and ceiling tiles were replaced du ring interval 1; a major earthquake occurred during interval 2. RESULTS: 72 case-patients and 433 patients with respiratory colonization we re identified. Acquisition was nosocomial for 18 (25.0%), indeterminate for 9 (12.5%), and community-acquired for 45 (62.5%) case-patients. Seventeen (23.6%) of the 72 case-patients had prior transplants, including 15 solid o rgan and 2 bone marrow. The IPA rate per 100 solid organ transplants (SOTs) decreased from 2.45 during interval 1 to 0.93 during interval 2 and to 0.5 2 during interval 3 (chi-square for trend, 5.44; P < .05). The hospitalwide IPA rate remained stable at 0.03 per 1,000 patient days. CONCLUSIONS: The SOT IPA rate decreased after intervals 1 and 2, although t he hospitalwide IPA rate remained stable during the study period. Post-eart hquake hospital demolition and construction occurring after interval 2 was not associated with an increase in the rate of IPA at our institution.