Air Sampling for Fungus around Hospitalized Patients with Coronavirus Disease 2019

Abstract

The risk of developing coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) depends on factors related to the host, virus, and treatment. However, many hospitals have modified their existing rooms and adjusted airflow to protect healthcare workers from aerosolization, which may increase the risk of Aspergillus exposure. This study aimed to quantitatively investigate airborne fungal levels in negative and slightly negative pressure rooms for COVID-19 patients. The air in neutral pressure rooms in ordinary wards and a liver intensive care unit with high-efficiency particulate air filter was also assessed for comparison. We found the highest airborne fungal burden in recently renovated slightly negative air pressure rooms, and a higher airborne fungal concentration in both areas used to treat COVID-19 patients. The result provided evidence of the potential environmental risk of CAPA by quantitative microbiologic air sampling, which was scarcely addressed in the literature. Enhancing environmental infection control measures to minimize exposure to fungal spores should be considered. However, the clinical implications of a periodic basis to determine indoor airborne fungal levels and further air sterilization in these areas remain to be defined.

Keywords: COVID-19; air sampling; fungus; invasive aspergillosis.

Figure 1

The median and interquartile range (IQR) of total fungal and A. fumigatus-like colonies in the air of different hospital environments. Negative pressure rooms (A), slightly negative pressure rooms (B), neutral pressure rooms in ordinary wards (C), and rooms in a liver intensive care unit with high-efficiency particulate air filter (D). The highest air fungal burden, either total fungal colonies or A. fumigatus-like colonies, was found in the slightly negative pressure rooms (B). In addition, there were higher airborne fungal concentrations in both negative and slightly negative pressure rooms (A,B) arranged for COVID-19 patients than the rooms in the ordinary ward (C) and liver intensive care unit with high-efficiency particulate air filter (D).

Figure 2

Representative agar plates inoculated by airborne fungi from the different hospital environments. Slightly negative air pressure rooms which had recently been renovated (A). Negative air pressure rooms (B). Rooms in the ordinary ward (C). Before and after environmental disinfection with ultraviolet-C (UV-C) irradiation (254 nm) in a liver intensive care unit room (D,E).