Search for environmental allergens in indoor samples using molecular techniques

Abstract

Indoor air quality is one of the most important factors that significantly influence the life quality of the population. Indoor environments are characterized by several sources of pollution, and the health problems associated with bad indoor air quality have acquired high importance in recent years. The biological particles present in the indoor environment can be of various types between viruses and bacteria, especially pollen grains and fungal spores. As people spend a lot of time indoors and many people suffer from respiratory problems such as pollinosis, pollen or its allergenic particles, it has been the subject of many studies. The pollen detected in the indoor environment is usually dependent on the concentration of pollen in the outdoor air, particularly of vegetation existing near the living areas. In "healthy" homes and buildings most of the fungi present come from external sources and the total number of fungi is lower than in the outdoor environment. General identification techniques are based on optical microscopic observation; however, it is time-consuming, it needs a taxonomist, and it is not possible to identify large amounts of samples. Molecular biology techniques are becoming more used and faster for indoor allergens identification and can be useful in outbreak prevention. Electrostatic dust fall collectors (EDC) were used for indoor sample collection and placed in places where people and animals pass, i.e. near the entrance door of the house, living room or bedroom, for 1 week. Eighteen volunteers participated in this study. The EDCs were rinsed in sterile water which was used for total DNA extraction. For Real-Time PCR fungal detection, the ITS region was considered, and for airborne pollen detection, the trnL gene was selected. PCR results showed an amplification curve and a respective melting peak in all the samples for the ITS gene, and 8 out of 18 were positive for the trnL gene. Electrophoresis results showed 2 bands, demonstrating the presence of, at least, 2 different fungal species. For pollen species, only 1 band could be seen. These positive results for pollen presence were seen in samples placed next to windows. The results show that it is possible to identify different biological particles, of different species, in an indoor environment, but also that it is possible to give a more assertive response to the population and to act preventively.