Aspergillus spp. burden on filtering respiratory protective devices: Is there an occupational health concern?

There is scientific evidence that associates occupational exposure to fungi in the waste industry to health outcomes, being Aspergillus genera reported as the most prevalent. During Filtering Respiratory Protective Devices (FFR) use, humidity and temperature conditions provide favorable conditions for Aspergillus growth. The aim of this study was to characterize Aspergillus burden retained by FFR interior layer and exhalation valve. The sample consisted of 120 FFR and the correspondent interior layer and exhalation valves collected from different workstations from one waste sorting industry. The fungal content of exhalation valve and from the interior layer of the each FFR was extracted and inoculated on malt extract agar (MEA) supplemented with chloramphenicol (0.05%) and dichloran-glycerol agar (DG18). FFR extracts were also used for the molecular detection of Aspergillus sections Flavi and Fumigati. Valves presented Aspergillus spp. as the most prevalent genera on MEA media (44.4%), unlike what was observed in the FFR interior layer, where Aspergillus spp. was not the most prevalent genera (6.84% MEA; 5.2% DG18). Among the Aspergillus genera, section Fumigati was the one with highest prevalence, both in exhalation valves (76.57% MEA; 87.24% DG18) and interior layer (75.81% MEA; 51.22% DG18). qPCR analysis successfully amplified DNA from the Aspergillus sections Flavi and Fumigati. Interior layers presented statistically significant differences showing higher number of FFR contaminated with higher levels of Aspergillus in the workstations where workers contact directly with waste. This work, revealing strong fungal contamination of FFR used by workers at waste industry, clearly indicates that future trials to test FFR protective efficacy and establishment of times for FFR replacement should be performed.