Brazilian legislation requires air conditioning systems in hospitals and establishes minimum standards for air quality, according to ABNT NBR 17037 and NBR 7256. Microbiological air analysis allows the identification and quantification of pathogenic filamentous fungi such as Fusarium sp. and Aspergillus sp., which are important quality indicators, especially in environments with immunosuppressed patients, where values >1 CFU/m³ are not permitted. Infections caused by these agents are associated with high morbidity and mortality in this population. Based on a detailed analysis of microbiological air reports, the affected beds, fungal species identified, and CFU counts were determined. From these findings, a multifaceted and integrated strategy was developed involving the Infection Control Service (SCIH), Engineering, Hospital Administration, and unit leadership. The bone marrow transplantation (BMT) unit has 12 inpatient beds with positive pressure and HEPA filtration in all rooms, divided into two corridors with distinct air conditioning systems. Levels ranging from 7 to 84 CFU/m³ of Alternaria sp. and Rhizopus sp. were detected in 100% of the beds. Initially, the highest-risk patients (allogeneic BMT) were removed from the unit, freeing 50% of the area (Side A). Subsequently, duct inspection and cleaning (by a specialized company), air filter replacement, terminal cleaning of the unit (housekeeping and nursing teams), structural repairs (Infrastructure), ozone application, and electrostatic spraying with hydrogen peroxide were performed. After these interventions, the air system was requalified and new samples were collected. The same measures were applied to Side B after patient transfer. Cleaning protocols were revised to include areas such as machine rooms and shafts. After 25 days of work within the unit, microbiological air samples were negative. During this period, the unit was closed, limiting access to treatment. Alignment of preventive actions against filamentous fungi in the BMT unit requires a continuous cycle of monitoring and adjustment. The identification of filamentous fungi in air quality reports serves as an immediate trigger for reviewing and intensifying environmental control strategies. Although legislation does not mandate more frequent microbiological air analysis, the team established a collection interval every 45 days.
Fonseca et al. (Sun,) studied this question.
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