Quantitative and Qualitative Airborne Mycobiota Surveillance in High-Risk Hospital Environment

(1) Background: The primary aim of the presented study was to assess the prevalence of fungi in the indoor air of selected hospital wards, and the additional goal was to evaluate the susceptibility of cultured isolates of Aspergillus fumigatus to triazoles. (2) Methods: Three hematology departments and a hospital for lung diseases were surveyed in 2015 and/or 2019. Air samples were taken with a MicroBio MB1 air sampler on Sabouraud agar. The susceptibility of Aspergillus fumigatus isolates to voriconazole, posaconazole and itraconazole was tested with a microdilution method, according to EUCAST. (3) Results: The amount of fungi cultured from rooms equipped with sterile air circulation, as well as flow devices for air disinfection, was significantly lower compared to that from unprotected rooms. The areas most contaminated with fungi were corridors and bathrooms. The dominant species were Cladosporium and Penicillium. A. fumigatus was rare in hematological departments (6/61, 9.8% examinations performed in 2014 and 2/40, 5% in 2019), whereas in the hospital for lung diseases an outbreak of A. fumigatus spores with up to 300 CFU/m(3) was noted in March 2015. No triazole-resistant A. fumigatus isolate was detected. (4) Conclusions: Regular microbiological testing of the hospital environment can contribute to the detection of spore outbreaks, and thus enable the implementation of corrective procedures (e.g., additional disinfection, changing of HEPA filters).

Automated summary

The primary aim of this study was to assess the prevalence of fungi in selected hospital wards and evaluate the susceptibility of Aspergillus fumigatus isolates to triazoles. Air samples were collected and cultured on Sabouraud agar. The study found that protected rooms with sterile air circulation and air disinfection devices had significantly lower amounts of cultured fungi compared to unprotected rooms. The most contaminated areas were corridors and bathrooms, with Cladosporium and Penicillium being the dominant species. A rare outbreak of A. fumigatus spores was noted in a hospital for lung diseases but no triazole-resistant isolates were detected. Regular microbiological testing of the hospital environment can help detect spore outbreaks and enable corrective procedures.