A cluster of pseudofungemia associated with hospital renovation adjacent to the microbiology laboratory.

ABSTRACT

OBJECTIVE: To determine the clinical significance and source of fungemia following a cluster of positive blood cultures during a 3-day period. DESIGN: Chart review was used to determine the clinical significance of positive blood cultures. Microbiologic sampling of the laboratory environment was used to determine potential sources of fungal contamination. SETTING: A large, tertiary care, community teaching hospital. PATIENTS All patients with blood cultures positive for Aspergillus species, Penicillium species, or both during the outbreak period. RESULTS: Thirteen patients, all children, were reported to have positive blood cultures for fungus during a 3-day period in early 1990. None had clinical features consistent with fungemia. Investigation of specimen processing procedures revealed that microbiologic plates were not processed--as per protocol--under the biologic hood but inadvertently were left open to air on the work bench by laboratory technicians. Settling plates left at the workbench, at door entry sites, and at sites of renovation immediately adjacent to the laboratory were positive for Aspergillus and/or Penicillium; control plates placed elsewhere were negative. Airflow patterns suggested spread into the microbiologic laboratory through an open door located near the implicated workbench station and a false ceiling above the workbench area. CONCLUSIONS: Our investigation demonstrates that faulty technique in the laboratory coupled with a change in environmental conditions can result in false-positive cultures and an outbreak of pseudofungemia.