MONITORING OF FUNGI GENERA IN THE FLOOR DUST AND THE INDOOR AIR OF ELEMENTARY AND PREPARATORY SCHOOLS IN THE CITY OF ZAWIA, LIBYA
Abdel-Kareem Mohamed El-Basheer, Altayeb Elazomi*, Abdurraouf Zaet, Azab Elsayed Azab, A. Dhawi and Fathi Abdallah Shakurfow
Background: Spores of fungi, bacteria and actinomycetes are always present in large number in dusts and indoor air of schools. Some of these fungi are recognized to play a role in causing human and animal diseases. Studying the different groups of fungi such as spores and mycelium fragments of mesophilic (glucophilic, pathogenic and keratinophilic) fungi is of considerable important. Objectives: The present investigation is aimed to study the occurrence, the distribution, the seasonal variations, and the fluctuations of the fungi inhabiting dusts and indoor air of elementary and preparatory schools at Zawia governorate. Methods: Fifty floor dust samples were collected during January to April 2006 from different Elementary and Preparatory schools at Zawia city. Also, twenty-four floor dust samples were collected fortnightly during January-December 2006 from classrooms of Al-Shabbani Bin Nasart School at Zawia city. All samples were stored at a refrigerator (2-5 °C) till use. Modified-Czapek's agar medium used for isolation ofglucophilic fungi and Sabourauddextrose agar medium was used for isolation of pathogenic fungi. Theisolation of keratinophilic fungi was achieved by hair baiting technique. The developing colonies were counted, examined, identified and the total number of eachgenuswas calculated. Results: 18 genera of Glucophilic fungi, 11 Pathogenic fungi genera, and 13 Keratinophilic fungi genera were isolated from 50 floor dust samples. The most common Glucophilic fungi genera were: Alternaria, Aspergillus, Cladosporium, Emericella, Fusarium, Mucor, Penicillium, and Ulocladium were isolated in high frequencies of occurrence. Pathogenic fungal genera; Alternaria, Aphanoascus, Aspergillus, Mucor and Penicillium were recovered in high frequencies of occurrence as well on Sabouraud dextrose agar. The most common Keratinophilic fungi genera were: Alternaria, Aphanoascus, Aspergillus and Trichophyton. The average maximum and minimum temperature of the air of Al-Sabbani Bin Nazart elementary school during the experimental period ranged between 20° - 36°C and l0°C-26 °C, respectively. The average maximum and minimum relative humidity fluctuated between 60 -95 % and 8-24%, respectively. The monthly counts of Glucophilic fungi genera irregularly fluctuated and the highest count was estimated during spring and the lowest in summer. The monthly counts of pathogenic and keratinophilic fungi were irregularly fluctuated and varied giving peaks in January and December and minima during August and June, respectively. The monthly counts of airborne fungi fluctuated irregularly and the peak was found in winter. The monthly counts of Pathogenic and keratinophilic fungal genera irregularly fluctuated giving peaks during December and April, respectively. Conclusion: It can be concluded that a various fungal genera were isolated from floor dust, and indoor air samples. The most prevailed fungal genera isolated were Alternaria, Aspergillus, Penicillium, Mucor, Ulocladium, Emericella and Rhizopus. Overall, the highest number of fungal genera was obtained from floor dust samples. Our results obtained of pathogenic and non-pathogenic fungi in the floor dust and indoor air of Elementary and Preparatory schools were almost basically similar to those fungi in many parts of the world but with different numbers, frequencies and months of fungi. Further studies on mycoflora taxa frequently isolated from floor dust and indoor air environment of schools in different governorates of Libya would be interesting. A large number of fungal species still waiting proper identification. Different modern sampling techniques can be used to investigate culture ability and total fungal spores and to estimate Colony Forming Units (CFU).
Keywords: Fungi genera, Floor dust, Indoor air, Elementary schools, Preparatory schools, Zawia governorate.
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