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Updated: May 6, 2026
Collection and Extraction of Occupational Air Samples for Analysis of Fungal DNA
Published on: May 2, 2018
Accessing indoor fungal contamination using conventional and molecular methods in Portuguese poultries
C Viegas1, J Malta-Vacas, R Sabino
1Environmental Health RG, Lisbon School of Health Technology, Polytechnic Institute of Lisbon, Av. D. João II, Lote 4.69.01, 1990-096, Lisbon, Portugal, carla.viegas@estesl.ipl.pt.
Abstract:
Epidemiological studies showed increased prevalence of respiratory symptoms and adverse changes in pulmonary function parameters in poultry workers, corroborating the increased exposure to risk factors, such as fungal load and their metabolites. This study aimed to determine the occupational exposure threat due to fungal contamination caused by the toxigenic isolates belonging to the complex of the species of Aspergillus flavus and also isolates from Aspergillus fumigatus species complex. The study was carried out in seven Portuguese poultries, using cultural and molecular methodologies. For conventional/cultural methods, air, surfaces, and litter samples were collected by impaction method using the Millipore Air Sampler. For the molecular analysis, air samples were collected by impinger method using the Coriolis μ air sampler. After DNA extraction, samples were analyzed by real-time PCR using specific primers and probes for toxigenic strains of the Aspergillus flavus complex and for detection of isolates from Aspergillus fumigatus complex. Through conventional methods, and among the Aspergillus genus, different prevalences were detected regarding the presence of Aspergillus flavus and Aspergillus fumigatus species complexes, namely: 74.5 versus 1.0 % in the air samples, 24.0 versus 16.0 % in the surfaces, 0 versus 32.6 % in new litter, and 9.9 versus 15.9 % in used litter. Through molecular biology, we were able to detect the presence of aflatoxigenic strains in pavilions in which Aspergillus flavus did not grow in culture. Aspergillus fumigatus was only found in one indoor air sample by conventional methods. Using molecular methodologies, however, Aspergillus fumigatus complex was detected in seven indoor samples from three different poultry units. The characterization of fungal contamination caused by Aspergillus flavus and Aspergillus fumigatus raises the concern of occupational threat not only due to the detected fungal load but also because of the toxigenic potential of these species.
Insights
Poultry workers face occupational threats from Aspergillus flavus and Aspergillus fumigatus fungal contamination. Molecular methods detected toxigenic strains missed by culture, highlighting risks from fungal load and mycotoxins.
Area of Science:
- Environmental microbiology
- Occupational health
- Mycology
Background:
- Poultry workers exhibit increased respiratory issues linked to fungal exposure.
- Fungal metabolites and high fungal loads pose significant occupational risks.
- Aspergillus flavus and Aspergillus fumigatus species complexes are common contaminants.
Purpose of the Study:
- To assess occupational exposure risks from toxigenic Aspergillus flavus and Aspergillus fumigatus in Portuguese poultry facilities.
- To compare conventional and molecular methods for detecting these fungal species.
- To evaluate the threat posed by fungal contamination and its toxigenic potential.
Main Methods:
- Air, surface, and litter samples were collected from seven Portuguese poultry farms.
- Conventional methods involved air impaction and surface/litter culturing.
- Molecular analysis utilized real-time PCR on air samples for specific Aspergillus detection.
Main Results:
- Aspergillus flavus was prevalent in air (74.5%) and surfaces (24.0%) via culture; Aspergillus fumigatus was less common.
- Molecular methods detected aflatoxigenic Aspergillus flavus strains missed by culture.
- Aspergillus fumigatus complex was identified in more samples using molecular techniques than conventional methods.
Conclusions:
- Fungal contamination by Aspergillus flavus and Aspergillus fumigatus presents a significant occupational health concern in poultry settings.
- Molecular detection is crucial for identifying toxigenic fungal strains, including those not culturable.
- The study underscores the need for robust monitoring and control of fungal exposure in poultry environments.
