Electrostatic dust cloths (EDC) have been widely used for microbiologic contamination assessment in different indoor and occupational environments. Electrostatic dust cloths are negatively charged allowing dust particles to settle with greater ease.
Indoor Environment | Study Goal | Sampling Methods | Analyses Performed to EDC | Most Relevant EDC Fungal Results | Main Conclusions | Reference |
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One veterinary clinic | Assessment of organic dust and microbial contamination in a typical Portuguese veterinary clinic, including azole-resistant fungi. | Active (air impaction N = 8) and passive (surfaces N = 8 and EDC N = 3) |
Culture-based methods (fungi and bacteria and azole resistance screening) and qPCR (Aspergillus sections detection) | EDC results evidenced the presence of Fusarium equisetii and Cladosporium sp. on MEA and DG18, respectively. | The sampling protocol in veterinary clinics should comprise active and passive sampling methods. Culture-dependent and independent methods should be used to achieve a more complete characterization of the microbial contamination. | [11] |
Twelve bakeries | To analyze the adequacy of EDC for identifying the distribution patterns and exposure concentrations of particulate matter and microbial contaminants in bakeries. | Passive sampling method (EDC N = 33) and Particle counts and size distribution (0.3 µm, 0.5 µm, 1 µm, 2.5 µm, 5 µm, and 10 µm) measurement | Culture-based methods (bacteria and fungi) | Higher EDC mass was significantly correlated with higher fungal load on DG18 and with particle size distribution in different dimensions Penicillium sp. (42.56%) was the most frequent fungi. | EDC was useful for identifying critical workplaces regarding exposure to particulate matter and microbial contamination. Results obtained suggest that EDC can be applied as a screening method in exploratory studies concerning particulate matter-exposure assessment and to quantify exposures in specific occupational environments. | [10] |
Thirteen bakeries | To assess workers´ exposure to fungi and mycotoxins in Portuguese bakeries. | Active methods (Air impaction and impingement each N = 53) and passive (surface swabs N = 58, EDC N = 36 and settled dust N = 11) methods | Culture-based methods (fungi) and qPCR (Aspergillus sections) | A. section Fumigati presented 50% of prevalence on DG18. it was possible to detect section Fumigati in 7.4% on EDC samples |
A wide number of sampling methods (active and passive) and different assays (culture-based and molecular methods) should be employed to obtain a refined risk characterization regarding fungi and mycotoxins. | [14] |
Ten Primary Health Care Centres (PHCC) | Aspergillus distribution assessment in 10 PHCC | Active (impaction N = 81 and impingement N = 41) and passive (surface swabs N = 81, EDC N = 81, settled dust N = 10, and filters from HVAC system N = 12) methods | Culture-based methods (Aspergillus prevalence) and qPCR (Aspergillus sections) | Fumigati section presented 1.3% of prevalence on EDC | One PHCC was not in compliance with IAQ Portuguese law since Aspergillus section Fumigati counts surpassed the quantitative guideline. The results of this study show that Aspergillus is widely spread in PHCC. The use of a multi-approach sampling protocol with selective media should be the trend in regular assessments performed in clinical environments. | [12] |
To analyze the adequacy of EDC for identifying critical workstations of occupational exposure to particulate matter and for characterizing the microbial contamination present in 10 PHCC. | Particle counts and size distribution were measured with direct-reading equipment. Passive sampling method (EDC N = 81) | Culture-based methods (bacteria and fungi) and qPCR (Aspergillus sections) | In MEA A. section Fumigati was observed in smaller counts (0.01%) and it was identified in the cleaning supply room. | The EDC was useful for unveiling the microbial contamination on the assessed PHCC. | [15] | |
One Central Hospital from Oporto | To assess the exposure to bioburden in one central hospital with a multi-approach protocol using active and passive sampling methods. | Active methods (impaction N = 120, filtration N = 2, and impingement N = 15) and passive (surface swabs N = 45, EDC N = 15 and settled dust N = 5; HVAC filter samples N = 2) | Culture-based methods (fungi and bacteria and azole resistance screening) and qPCR (Aspergillus sections). Mycotoxins and endotoxins profile were also assessed. Two cytotoxicity assays were conducted with two cell lines and in vitro pro-inflammatory potential was assessed | Fumigati section was observed in all the samples where culture-independent tools were applied including EDC (100%, 15 samples out of 15). | A multi-approach concerning sampling and analysis methods should be applied in the hospital environment | [13] |
Different occupational and nonoccupational indoor settings | Molecular identification of Aspergillus species collected | Several environmental matrices depend on the indoor environment. EDC was used in 4 out of the 7 environments assessed | Culture-based methods (Aspergillus and azole resistance screening from the isolates) and molecular identification | Five Aspergillus isolates obtained from EDC were selected for further analyses (A. welwitschiae (n = 2), A. tubingensis (n = 1), A. fumigatus sensu stricto (n = 1) and A. clavatus sensu stricto (n = 1)) | Resistance profile of Aspergillus in specific indoor environments was characterized. Aspergillus epidemiology characterization allows a complete risk characterization concerning Aspergillus burden. | [31] |
One Central Hospital from Lisbon | Bioburden assessment with two passive sampling methods (ventilations grids swabs and electrostatic dust collectors (EDC) at Clinical Pathology Services. | Surface swabs (N = 30) from ventilation grids and EDC (N = 16) | Culture-based methods (fungi and bacteria and azole resistance screening) and qPCR (Aspergillus sections). Mycotoxins assessment and cytotoxicity profile was also performed |
Aspergillus section Fumigati was detected in 7 EDC samples (7 out of 12; 58.33%). | The use of the two sampling methods—swabs and EDC—allowed us to obtain a more complete characterization of the microbial contamination. Culture-dependent and independent methods used side by side allow to perform an accurate characterization of the A. section Fumigati contamination. | [18] |
Thirty-three dwellings and four schools | To assess microbial contamination in the indoor microenvironments more frequented by children | PM2.5 and PM2.5–10 was sampled with a medium volume sampler. EDC was placed in the living room (N = 33) and in the children’s bedroom (N = 31), and in schools (N = 4) | Culture-based methods (fungi and bacteria and azole resistance screening) and qPCR (Aspergillus sections) | The fungal species most frequently found in bedrooms was Penicillium sp. (91.79%), while, in living rooms, it was found Rhizopus sp. (37.95%) was the most prevalent. Aspergillus sections with toxigenic potential were observed in bedrooms and living rooms and were able to grow on VOR. | Future studies, applying EDC sampling method coupled with PM assessment, should be performed to allow for a long-term integrated sample of organic dust. | [16] |
Twenty-three dwellings | To assess settleable dust loading rates and microbial contamination in Portuguese dwellings by passive sampling (quartz fiber filters and EDC, respectively.) | Quartz fiber filters were placed side by side With EDC in summer (N = 79) and winter (N = 78) | Culture-based methods (fungi and bacteria and azole resistance screening) and qPCR (Aspergillus sections) | Dust and microbial contamination showed higher variability in the summer season. In both seasons, Penicillium sp. was the most prevalent (59.1% winter; 58.1% summer), followed by Aspergillus sp. in winter (13.0%). Fungal contamination increased in the winter period, whereas bacterial counts decreased. In the winter season, Aspergillus sections Circumdati and Nidulantes were detected in VOR supplemented media; Aspergillus sections Fumigati and Nidulantes were detected by molecular tools. | Passive sampling methods should be applied in sampling campaigns on dwellings. Azole resistance screening should be performed in dwellings, and culture-dependent and independent methods should be employed when assessing indoor microbial contamination. | [17] |
Ten dwellings | Assessment of the bioburden during sleeping periods in Portuguese dwellings through active (air sampling) and passive (EDC) methods | Active sampling using a MAS-100™ air sampler equipment and EDC (from 7 bedrooms, 4 living rooms, and 1 kitchen) (N = 12) | Culture-based methods (fungi and bacteria and azole resistance screening) and qPCR (Aspergillus sections) | In bedrooms, the most found was Penicillium sp. (59.01% MEA; 96.54% DG18), in living room was Aspergillus section Circumdati on MEA (63.63%) and Cladosporium spp. on DG18 (100%), and in the kitchen was Penicillium sp. (100% MEA; 100% DG18). Aspergillus sp. in EDC ranged from 0 to 405.3 CFU/m2/day on MEA, while in DG18 Aspergillus species were not observed. | Bacterial increased during the sleeping period. Toxigenic fungal species and indicators of harmful fungal contamination, belonging to Aspergillus genera were identified indoors, as well as reduced susceptibility to antifungal drugs of some fungal species. | [20] |
Thirty dwellings | To assess the deposition rates of total settleable dust and microbial contamination in the indoor air of dwellings onto quartz fiber filters andEDC, respectively | 47 mm diameter quartz fiber filters were exposed to collect particulate matter and EDC (N = 30) were used for microbial contamination characterization | Culture-based methods (fungi and bacteria and azole resistance screening) and qPCR (Aspergillus sections) | Fungal contamination ranged from 1.97 to 35.4 CFU m−2 day−1 in MEA, and from undetectable to 48.8 CFU m−2 day−1 in DG18. Penicillium sp. was the most found in MEA (36.2%) and Cladosporium spp. in DG18 (39.2%). | Settleable dust and fungal contamination were increased in dwellings with pets; Indicators of harmful fungal contamination were present indoors; Aspergillus section Candidi was identified in azole supplemented media (VOR and POS); Specific housing typologies and characteristics influenced the microbial contamination. | [19] |
Twelve ambulances vehicles | Assessment of the bioburden in Portuguese ambulances using active and passive sampling methods. | 336 air samples through impaction method, 132 surface swabs, 7 mops, and cleaning cloths, 3 uniform ranks, 13 settled dust samples, and 14 EDC | Culture-based methods (fungi and bacteria and azole resistance screening) and qPCR (Aspergillus sections) and mycotoxins detection | Fungal values ranged from 0 to 23 CFU m−2 day−1 in MEA, and 0 (to 28.3 CFU m−2 day−1 in DG18. C. sitophila was the most prevalent fungal species in EDC. Mycotoxins were detected in EDC. | EDC was useful for the fungal contamination characterization and also for mycotoxins detection on ambulances. Further studies are needed to determine the potential risk of infection transmission between different vehicles and under different conditions of use. | [22] |
Eleven Firefighters headquarters (FFH) | Characterization of Aspergillus section Fumigati distribution in 11 firefighter headquarters (FFHs) to obtain an accurate occupational exposure assessment. | Active (air impaction method) (N = 760) and passive sampling methods (floor surfaces swabs (N = 90), electrostatic dust collectors (EDC) (N = 82), settled dust (N = 11), filters used for sampling the settled dust (N = 90), firefighter uniform badges (N = 67), cleaning cloths (N = 25) and mops N = 14). | Culture-based methods (fungi and azole resistance screening) and qPCR (Aspergillus sections) | Aspergillus genera was predominant in EDC from FFH4 (0.55%), whereas in FFH2, the section Fumigati was the most frequent in EDC (100%). The Fumigati section was predominant among Aspergillus genus in EDC samples in MEA (28.57%). Concerning azole resistance screening, Aspergillus genera were identified only in mops, EDC, settled dust filters, and settled dust. The Fumigati section was prevalent in the SDA of 4.4% in EDC and was the only section found in ITR (EDC: 100%) and the most observed in VOR (EDC: 97.1%). The same sectionwas detected by qPCR in almost all passive samples, with EDC being the sampling method with the highest prevalence (n = 61; 67.8%). |
This study confirms the widespread of Aspergillus sp. in all FFHs. Fumigati section was identified in all FFHs as well as fungi potentially resistant to azoles. | [21] |
Health Care Environments (10 Primary Health Care Environments (PHCC) and 1 Central Hospital (CH)) | Cytotoxicity evaluation of Aspergillus section Fumigati | Active sampling (air sampling by impaction N = 201 andimpigment N = 56 for molecular detection purposes). Passive sampling (surface swabs–N = 126; EDC, N = 96; settled dust N = 15; and filters from HVAC system N = 12). Nasal swabs were collected from volunteer health care workers in the 10 PHCC (N = 25) and in the CH (N = 22). |
Aspergillus Section Fumigati isolation by culture-based methods (including azole resistance screening) and cytotoxicity assessment in lung epithelial cells and kidney cells using the MTT assay. | 1 isolate was recovered from EDC with a high level of cytotoxicity in both cell lines (A549 and SK cell lines) | Further studies should address the epidemiology and clinical relevance of Aspergillus section Fumigati, as well as the mechanisms underlying Aspergillus-mediated cytotoxicity. | [23] |