Negative-Pressure ICU Rooms and Pulmonary Aspergillosis: The Impact of Room Conversion
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By
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Philippe Ichai
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Faouzi Saliba
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Audrey Coilly
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Asma Jeblaoui
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October 12, 2026
Clinical Report: Negative-Pressure ICU Rooms and Pulmonary Aspergillosis
Overview
Evidence presented in the correspondence is mixed: a multicenter observational analysis found lower 60-day incidence of probable IPA in negative-pressure rooms under FUNDICU criteria, whereas reports involving converted rooms described environmental Aspergillus and higher hospital-acquired rates. Differences in room design and ventilation, alongside less frequent mycological testing in negative-pressure rooms, limit causal interpretation of the observed association.
Background
COVID-19-associated pulmonary aspergillosis is an important concern in mechanically ventilated ICU patients, and room ventilation may influence environmental fungal exposure. Negative-pressure rooms are used for airborne infection isolation, but a room converted from positive to negative pressure may not have the configuration or ventilation performance of a purpose-built isolation room. The correspondence describes room configuration, airflow, filtration, exhaust, airtightness, and air-exchange rates as relevant environmental factors. It also notes that diagnostic testing practices can affect detection of probable IPA.
Data Highlights
| Evidence | Reported findings |
|---|---|
| Converted ICU rooms, 2020 report | Probable or proven pulmonary aspergillosis occurred in 6 of 26 patients; 2 additional patients were colonized by Aspergillus fumigatus. Air sampling detected A. fumigatus in several rooms involving affected patients. Airborne concentrations fell and became undetectable after surface disinfection and progressive pressure modification toward neutral or mildly positive levels; antifungal prophylaxis in remaining patients prevents attributing the absence of subsequent cases to pressure modification alone. |
| Multicenter cohort reported by Kreitmann et al. | Among 1,233 mechanically ventilated patients across 75 ICUs, negative-pressure room exposure was associated with lower 60-day cumulative incidence of probable IPA defined by FUNDICU criteria. The correspondence provides no incidence estimates and notes that the observational association does not establish a protective effect. |
| Mycological testing in the multicenter cohort | Bronchoalveolar lavage with mycological testing was performed in 5.8% of patients in negative-pressure rooms versus 22.3% in neutral-pressure rooms; serum galactomannan testing was performed in 14% versus 26%, respectively. |
| Outcome definitions | The lower incidence was observed for probable IPA under FUNDICU criteria. No significant association was reported for putative IPA defined by AspICU or for the composite of putative IPA and Aspergillus colonization. |
| Two-hospital observations reported by Biebelberg et al. | Hospital-acquired Aspergillus rates were higher at the institution using negative-pressure rooms more extensively; after use was reduced, rates decreased and became comparable between hospitals. The observations do not demonstrate causality. |
Key Findings
- In the 2020 report of converted ICU rooms, 6 of 26 patients developed probable or proven pulmonary aspergillosis and 2 others were colonized by A. fumigatus.
- Air sampling identified A. fumigatus in several rooms involving affected patients; airborne concentrations declined after surface disinfection and progressive pressure modification, although concurrent antifungal prophylaxis limits attribution of subsequent outcomes.
- Kreitmann et al. reported lower 60-day cumulative incidence of FUNDICU-defined probable IPA among negative-pressure room-exposed patients in a cohort of 1,233 mechanically ventilated patients across 75 ICUs; the observational design cannot establish protection.
- Mycological investigations were less frequent in negative-pressure rooms: bronchoalveolar lavage with mycological testing occurred in 5.8% versus 22.3%, and serum galactomannan testing in 14% versus 26%, compared with neutral-pressure rooms.
- The association differed by diagnostic definition: it was reported for probable IPA under FUNDICU criteria, but not for AspICU-defined putative IPA or the composite of putative IPA and Aspergillus colonization.
- Biebelberg et al. reported higher hospital-acquired Aspergillus rates at the hospital with more extensive negative-pressure room use; rates decreased after use was reduced, but the observations do not establish causality.
Clinical Implications
The correspondence cautions that negative-pressure exposure may represent different environmental conditions depending on room configuration and ventilation performance; pressure-gradient direction alone does not characterize an isolation environment. It also identifies differential mycological testing as a limitation that may have contributed to underdiagnosis and differential case detection in the multicenter analysis.
Conclusion
The reported association between negative-pressure ICU rooms and probable IPA is not consistent across the cited observations and varies by diagnostic definition. Room design and performance, environmental fungal burden, and diagnostic intensity remain important limitations in interpreting these findings.
Related Resources & Content
- Kreitmann et al., PubMed, 2026 -- Relationship between negative-pressure ICU rooms and the risk of COVID-19-associated pulmonary aspergillosis: an ancillary analysis of the COVID-ICU cohort study
- FUNDICU consensus group, PMC, 2024 -- Invasive Fungal Diseases in Adult Patients in Intensive Care Unit (FUNDICU): 2024 consensus definitions
- Biebelberg et al., source details not provided -- Observations on hospital-acquired Aspergillus and negative-pressure room use
- Schaffzin et al., source details not provided -- Commentary on air balance and airborne infection isolation room design
- Infection — Administration of nebulized liposomal amphotericin B and posaconazole for antifungal prophylaxis in critically ill patients with severe SARS-CoV-2 infection in the ICU
- ASCO Publications — Improved management of invasive pulmonary aspergillosis in neutropenic patients using early thoracic computed tomographic scan and surgery.
- Infection — Management and Diagnosis of Invasive Pulmonary Aspergillosis in Critically Ill ICU Patients: Summary of the German National Guidelines (AWMF 113-005)
- International Journal of Infectious Diseases — Post-COVID-19 Non-Invasive Aspergillosis Increases the Severity of SARS-CoV-2 Infections
- Invasive Fungal Diseases in Adult Patients in Intensive Care Unit (FUNDICU): 2024 consensus definitions
- Relationship between negative-pressure ICU rooms and the risk of COVID-19-associated pulmonary aspergillosis: an ancillary analysis of the COVID-ICU cohort study
- Invasive Fungal Diseases in Adult Patients in Intensive Care Unit (FUNDICU): 2024 consensus definitions from ESGCIP, EFISG, ESICM, ECMM, MSGERC, ISAC, and ISHAM - PMC
- Incidence, mortality and risk factors of invasive pulmonary aspergillosis in critically ill patients during the COVID-19 era: a global systematic review and meta-analysis - PubMed
Based on findings from:
Negative-pressure ICU rooms and pulmonary aspergillosis: room conversion matters
Philippe Ichai, Faouzi Saliba, Audrey Coilly, Asma Jeblaoui. Critical Care, 2026.
https://link.springer.com/article/10.1186/s13054-026-06371-5
This content is an AI-generated, fully rewritten summary based on a published scholarly article. It does not reproduce the original text and is not a substitute for the original publication. Readers are encouraged to consult the source for full context, data, and methodology.
