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In-hospital source of airborne Penicillium species spores
Abstract:
Between 16 July and 1 October 1984, prospectively monitored corridor air samples from a bone marrow transplant station revealed a marked increase in airborne thermotolerant Penicillium spores. Simultaneous cultures of outside air showed lower spore counts, which were unchanged before, during, and after the corridor outburst, establishing that the source was within the hospital. Although the corridor was equipped with recirculating high-efficiency particulate air filtration units which provided 16 air changes per h, the mean corridor air count rose to 64.4 thermotolerant Penicillium CFU/m3 during the outburst period. The in-hospital source was ultimately traced to rotting cabinet wood enclosing a sink with leaking pipes in the medication room. It produced approximately 5.5 X 10(5) thermotolerant Penicillium CFU/h. In a patient room supplied by corridor air, an in-room recirculating high-efficiency particulate air filter reduced the mean thermotolerant Penicillium count to 2.2 CFU/m3. No patient illness or colonization occurred as a result of this event, although the cabinet wood, after sterilization, was shown to sustain abundant growth of Aspergillus fumigatus and Aspergillus flavus. Wet organic substrates should be avoided in hospital areas with immunosuppressed patients.
Insights
A hospital medication room
Area of Science:
- Environmental microbiology
- Hospital infection control
- Mycology
Background:
- Airborne fungal spores pose a risk in healthcare settings, especially for immunocompromised patients.
- High-efficiency particulate air (HEPA) filtration is crucial for maintaining air quality in hospitals.
- Identifying indoor sources of fungal contamination is vital for preventing patient exposure.
Purpose of the Study:
- To investigate a significant increase in airborne thermotolerant Penicillium spores detected in a bone marrow transplant unit.
- To identify the indoor source of fungal contamination within the hospital environment.
- To assess the effectiveness of in-room HEPA filtration in controlling airborne fungi.
Main Methods:
- Prospective monitoring of airborne thermotolerant Penicillium spores in hospital corridors.
- Comparison of indoor air counts with simultaneous outdoor air samples.
- Trace-back investigation to identify the internal source of contamination.
- Assessment of fungal growth on potential substrates and effectiveness of HEPA filters.
Main Results:
- A marked increase in airborne thermotolerant Penicillium spores (mean 64.4 CFU/m3) was observed in the transplant unit corridor.
- The source was traced to rotting cabinet wood with leaking pipes in a medication room, producing approximately 5.5 x 10(5) CFU/h.
- In-room HEPA filtration significantly reduced airborne Penicillium counts to 2.2 CFU/m3 in a patient room.
- Sterilized wood supported growth of Aspergillus fumigatus and Aspergillus flavus.
Conclusions:
- Leaking pipes and rotting wood in a medication room served as a significant source of airborne thermotolerant Penicillium.
- Even with existing HEPA filtration, internal fungal proliferation can lead to high airborne spore counts.
- Avoiding wet organic substrates in proximity to immunocompromised patients is critical for infection control.