Invasive pulmonary aspergillosis in neutropenic patients during hospital construction: before and after chemoprophylaxis and institution of HEPA filters.

Between September 1993 and December 1993, during extensive hospital construction and indoor renovation, a nosocomial outbreak of invasive pulmonary aspergillosis occurred in acute leukemia patients treated in a regular ward that has only natural ventilation. The observed infection rate was 50%. Chemoprophylaxis with intravenous continuous low-dose amphotericin B was then instituted as a preventive measure. During the next 18 months invasive pulmonary aspergillosis developed in 43% of acute leukemia patients. After that period a new hematology ward was opened with an air filtration system through high-efficiency particulate air filtration (HEPA) filters, and a bone marrow transplantation program was started on the hematology service. During the following three years, none of the acute leukemia or bone marrow transplantation patients who were hospitalized exclusively in the hematology ward developed invasive pulmonary aspergillosis, although 29% of acute leukemia patients who were housed in a regular ward, because of shortage of space in the new facility, still contracted invasive pulmonary aspergillosis. Overall, 31 patients were diagnosed with invasive pulmonary aspergillosis during almost five years: 74% of patients recovered from invasive pulmonary aspergillosis, and 42% are long-term survivors; 26% of patients died of resistant leukemia with aspergillosis, but no one died of invasive pulmonary aspergillosis alone. In conclusion, during an on-going construction period, an extremely high incidence rate of invasive pulmonary aspergillosis in acute leukemia patients undergoing intensive chemotherapy was observed. Institution of low-dose intravenous amphotericin B prophylaxis marginally reduced the incidence rate of invasive pulmonary aspergillosis. Keeping patients in a special ward with air filtration through a HEPA system eliminated invasive pulmonary aspergillosis completely. Among patients who developed invasive pulmonary aspergillosis, early diagnosis and treatment are probably the explanation for the favorable outcome.