Table 2.
Methods used for collecting air and environmental samples, fungal identification, and measured total and specific airborne fungal levels during fungal outbreaks and infections associated with construction or renovation described in articles published from January 2015 to December 2022.
| Author, Year | Air Samples Collection | Environmental Samples Collection | Fungal Identification | Airborne Total Fungal Level | Airborne Specific Fungal Level | Environmental Samples Results |
|---|---|---|---|---|---|---|
| Barreiros, G. et al., 2015 [29] | Using a 6-stage Andersen air sampler (Andersen: Thermo Fisher Scientific, Inc. Waltham, MA, USA) which collects air at a rate of 28.3 L/min; each stage of the air sampler was filled with 90 × 15 mm plates containing 2% Sabouraud dextrose agar (DIFCO, Houston, TX, USA) with gentamycin (200 ug/mL). The samples were performed during 30 min in indoor areas and 5 min in outdoor areas. After sampling, the plates were incubated at 25 °C for at least 7 days. | not performed | Colony counts were performed weekly, and subcultures were made using potato dextrose agar (DIFCO), Czapek agar (DIFCO), lactrimel agar, oat agar, and malt extract agar. Identification of fungi was performed on the basis of morphological parameters, initially by observing the characteristics of colonies in a stereoscopic microscope. Subcultures were performed if the colonies had the characteristics consistent with clinically relevant fungi (Aspergillus, Fusarium, agents of mucormycosis, as well as Cladosporium and Penicillium). The most frequent species was A. niger complex. |
The concentration increased with values of 148.17 CFU/m3 in the historical period, 271.45 CFU/m3 during demolition, 1887.67 CFU/m3 on the day of implosion and 204.10 CFU/m3 in the postimplosion period. | Concentration of Aspergillus spp. varied significantly: 3.71 CFU/m3 in the historical period, 7.18 CFU/m3 in the demolition period, 22.5 CFU/m3 on the day of implosion, and 15.13 CFU/m3 of air in the postimplosion period. The mean concentration of agents of mucormycosis was low in all periods (0.2 CFU/m3 in the historical period, zero in the periods of mechanical demolition and implosion, and 0.1 CFU/m3 in the postimplosion period. Dematiaceous fungi other than Cladosporium spp. were encountered in small amounts (mean 3.45/m3). |
N/A |
| Gheith, S. et al., 2015 [30] | Air samples were collected at 100 cm from the patient’s bed and at 50 cm from the room entrance by using a Microflow portable air sampler (Aquaria Srl, Lacchiarella, Italy) that aspirates and inoculates airborne spores through a sampling grid onto the Sabouraud chloramphenicol medium. | Surface samples were collected by the swabbing with a moist cotton swab of 25 cm2 of each of the following surfaces: bed, window, curtain, door wrist, nightstand, table, and cupboard. Each sample was inoculated onto the Sabouraud–chloramphenicol medium (Bio-Rad). | Fungal colonies were identified and counted after a 5-day incubation at 27 °C. The identification of the filamentous fungi was based on both the macroscopic and microscopic characteristics of the colonies. Aspergilli were identified to the section level because morphological differentiation of species within the same section is questionable in a routine laboratory setting. Colony-forming units (CFU) were expressed per m2 and per m3 in surface and air samples, respectively. | In air samples, the total fungal contamination (CFUs) significantly correlated with Aspergillus spp., Aspergillus section Nigri and Aspergillus section flavi. | Aspergillus spp. CFU counts in air samples during 14 months of renovation was higher (8.1 vs 6 mean CFU/m3, p = 0.031) than during the period after work stopped. | The same pattern was observed (12.34 vs 6.8 mean CFU/m3, p = 0.00002) regarding Aspergillus CFU counts in surface samples. |
| Loschi, M. et al., 2015 [31] | Airborne Aspergillus concentrations were measured weekly by repeated air sampling in each department. Areas with positive samples were retested after corrective measures. Samples were collected using a Reuter Centrifugal Impaction (RCS) High Flow Air Center (Biotest Hycon, Germany) loaded with ready-to-use culture media on flexible agar strips with modified Sabouraud dextrose agar for yeast and molds, γ-irradiated in double wrapper to determine the total number of fungal spores in the air (Biotest Hycon, Germany). | not performed | When the cultures were positive, colonies were quantified as colony-forming units (CFU) per cubic meter (m3). Less than 20 CFU/m3 was considered acceptable in all areas except for ICU where 0 CFU/m3 was required. | not performed (only Aspergillus concentrations were measured) | Airborne spore levels ranged from 0 to 30 CFU/m3. There was an increased number of positive samples in the standard unit compared to the ICU (p < 0.0001). | N/A |
| Özen, M. et al., 2016 [32] | The level of airborne particulates in patients’ rooms to evaluate HEPA filter efficiency was randomly measured; the methods was not specified. | not performed | not specified | The levels of particulates in the patients’ rooms were within acceptable limits; the results were not specified. | not specified | N/A |
| Combariza, J. et al., 2017 [33] | not performed | not performed | N/A | N/A | N/A | N/A |
| Kabbani, D. et al., 2018 [34] | not specified | not specified | not specified | not specified; air sampling of potential common pre- and post-admission exposure links during this outbreak failed to reveal a common environmental source of infection. | not specified | not specified; environmental sampling of potential common pre- and post-admission exposure links during this outbreak failed to reveal a common environmental source of infection. |
| Wirmann, L. et al., 2018 [35] | The measuring apparatus MAS−100 (Merck Chemicals GmbH, Darmstadt, Germany) was used. The apparatus was placed 1m above ground level. For each sample, 500 L of air was collected on malt extract agar plates. The measuring head of MAS−100 was autoclaved between each sampling day. The agar plates were incubated at 50 °C for 48 h. | not performed | Samples that showed visible mold growth after the incubation period were examined microscopically to identify A. fumigatus. All A. fumigatus isolates were plated on to Sabouraud dextrose agar containing 4mg/L itraconazole to screen for azole resistance. Grown isolates were subjected to antifungal susceptibility testing for itraconazole, voriconazole, posaconazole, and isavuconazole, according to EUCAST standard 9.3. The cyp51A gene was sequenced for all isolates with elevated minimum inhibitory concentration against an azole, as described recently. All colonies identified microscopically as A. fumigatus were counted and documented as colony-forming units (CFU)/m3. Additionally, the number of colonies was corrected according to Feller. | not performed (only Aspergillus spp. concentrations were measured) | Mean concentrations of A. fumigatus spores did not differ significantly be-tween the three periods before (17.5 CFU/m³), during 30 (20.8 CFU/m³) (p = 0.26), and after demolition (17.7 CFU/m³) (p = 0.33). | N/A |
| Park, J.H. et al., 2019 [36] | Air sampling was conducted once a month in the three hematologic wards during the construction period. A total of 1000 L of air was collected three times every 20 min by using a portable air sampler (AirPort MD8, Sartorius AG, Germany) located at each nurse station. Air was plated onto Sabouraud dextrose agar and incubated at 30 °C for five days. | not performed | After incubation, colonies were counted, and the data expressed as median colony-forming units (CFU) per 1000 L of air. Colonies were identified at the genus level based on macroscopic and microscopic findings (lactophenol cotton blue-stained preparation). | The total mold spore level tended to be lower in period 2 (5.60 CFU/1000 L) with lighter works such as framing, interior designing, plumbing, and finishing in comparison to period 1 (9.95 CFU/1000 L) with heavier works such as demolition and excavation. | Aspergillus spore levels were also lower in period 2 (1.70 CFU/1000 L) than in period 1 (2.35 CFU/1000 L). | N/A |
| Boan, P. et al., 2020 [37] | One cubic meter of air for fungal culture was sampled in affected patients’ rooms, other areas of the hematology wards, the cancer outpatient center, the main hospital concourse, car park, and open grounds. | Swabs for fungal culture were taken from patient sinks and various other surfaces of patients’ rooms in the hematology wards. | not specified | not specified | Lomontospora prolificanswas was not found in air samples. | Lomontospora prolificans was not found in environmental samples. |
| Le Clech, L. et al., 2020 [38] | Air sampling was conducted with the MAS−100 biocollector (Merck, Darmstadt, Germany) using Sabouraud chloramphenicol plates. | Surface samples were collected using a biocontact applicator (Oxoid, Dardilly, France). | not specified | not specified (results were presented as percentage of positive samples) | A. fumigatus species complex and A. versicolor species complex were detected; level not specified (results were presented as a percentage of positive samples). | A. fumigatus species complex and A. versicolor species complex were detected; level not specified (results were presented as a percentage of positive samples). |
| Atilla, A. et al., 2022 [39] | not performed | not performed | N/A | N/A | N/A | N/A |
| Sathitakorn, O. et al., 2022 [40] | not specified | not performed | not specified | At the front of ICU, the nursing station, the index patient anterooms, and rooms, airborne fungal bioburdens from air sampling were 235–290 CFU/m3 at all sites; the baseline standard airborne fungal bioburden was <150 CFU/m3 for the ICU. | not specified | N/A |
ICU—intensive care unit; N/A—not applicable.