Aspergillus spp. prevalence in different Portuguese occupational environments: What is the real scenario in high load settings?

Abstract

The genus Aspergillus is one of the most prevalent regarding fungi in several highly contaminated occupational environments. The goal of the current study was to assess the prevalence of Aspergillus spp. in different settings, focusing on those where a higher load of fungal contamination is expected according to the European Agency for Safety and Health at Work. A specific protocol to ensure a more accurate assessment of the exposure to Aspergillus spp. is proposed aimed at allowing a detailed risk characterization and management. Two wastewater treatment plants, one wastewater elevation plant, four waste treatment plants, three cork industries, five slaughter houses, four feed industries, one poultry pavilion, and two swineries, all located in the outskirts of Lisbon, were assessed. In total, 125 air samples and 125 surface samples were collected and analysed by culture-based methods. Real-time polymerase chain reaction was performed to detect fungal presence in 100 samples, targeting the Aspergillus sections Circumdati, Flavi, and Fumigati. The highest prevalence of Aspergillus spp. was found in wastewater treatment plants (69.3%; 31.1%), waste treatment plants (34.8%; 73.6%), and poultry feed industry (6.3%; 26.1%), in air and surfaces, respectively. Aspergillus spp. was also prevalent in cork industry (0.9%; 23.4%), slaughter houses (1.6%; 17.7%), and swineries (7.4%; 9.5%), in air and surfaces, respectively. The Aspergillus sections more prevalent in the air and surfaces of all the assessed settings were the Nigri section (47.46%; 44.71%, respectively), followed by Fumigati (22.28%; 27.97%, respectively) and Flavi (10.78%; 11.45%, respectively) sections. Aspergillus section Fumigati was successfully amplified by qPCR in 18 sampling sites where the presence of this fungal species had not been identified by conventional methods. It should be highlighted that the occupational exposure burden is due not only to the Aspergillus load, but also to the toxigenic potential of this genus. Based on our results, a protocol relied in the application of conventional and molecular methods in parallel is herein suggested aimed at allowing a better risk characterization and management.

Occupational exposure to bioburden in Portuguese bakeries: an approach to sampling viable microbial load

“…Beside the sampling methods, the use of different fungal media (MEA and DG18 agar) allowed a more comprehensive insight into the problem, as it yielded different counts with the same sampling method, which has already been reported by others (20,24). Yet both media showed good sensitivity to fungi, and the combination of the two media has been shown to give complementary information (29)(30)(31). As for the bacteria, TSA provides information about bacterial contamination and VRBA is more specific for the Gramnegative coliforms.…”

Occupational Exposures to Organic Dust in Irish Bakeries and a Pizzeria Restaurant

“…In this scenario, it is difficult to distinguish in vitro susceptibility at a species level, thus, molecular identification is crucial to increase our knowledge of the susceptibility to antifungal agents. The fact that secondary resistance can emerge from environmental sources highlights the importance of the assessment of different settings outside of healthcare facilities [56][57][58][59][60].…”

Antifungal-resistant Mucorales in different indoor environments

“…For a better understanding of the Mucorales burden, the concentration can be assessed by culturebased and molecular methods such as qPCR (Viegas et al 2014). Of note, a similar approach has been suggested as a protocol for the assessment of Aspergillus in different occupational environments (Viegas et al 2017a), with the application of culture-based methods coupled with molecular tools to allow a more refined, integrated and useful data. Like Aspergillus qPCR, the Mucorales qPCR assay used in our study provides high analytical specificity and consequent high degree of aetiological certainty at the genus level (Springer et al 2016a).…”

“…Mucorales isolates were obtained from samples collected at independent projects aiming for the assessment of occupational exposure and indoor air quality, focusing on exposure to bioburden. Indoor environmental samples were collected between 2013 and 2018 from four different occupational settings around Lisbon metropolitan area, and from dwellings in Aveiro region (Portugal) (Table 1), as follows: bakeries (Caetano, Faria, et al 2017;Caetano, Zegre, et al 2018;Viegas et al 2018c), swine farms (Viegas, Carolino, et al 2013;Viegas, Faria, Dos Santos, et al 2016b;Viegas, Faria, Monteiro, et al 2018b), taxis used for patient transportation (Viegas et al 2018d), waste-sorting plants (Viegas, Gomes, et al 2014;Viegas, Faria, Dos Santos, et al 2015;Viegas, Faria, Caetano, et al 2017a), and dwellings (data not published). In order to collect and assess total bioburden and resistant mycobiota, different sampling devices were used per setting that were better adapted to the activities developed in each environment: electrostatic dust collector (EDC) from dwellings and bakeries; filters from the air-conditioning system of vehicles (taxis and waste fork lifters); litter and feed from swine farms; raw materials from bakeries (Table 1).…”