Assessing Dust for Potential Pathogenic Fungi in Office Floors

Abstract

Dust formation occurs as a result of separating lighter particles from the heavier ones by means of an upward directed stream of airborne organic and inorganic particulate matter that originates from a multiplicity of indoor and outdoor sources. The aim of this study was to determine the types of potential pathogenic fungi in dust in office floors. Dust samples were obtained from forty offices in three Departments and the College Administrative block. The samples were obtained from carpeted and uncarpeted offices. One gram of each sample was weighed and suspended in 10ml of sterile distilled water. One ml of the 1 in 10 diluted samples was inoculated onto Sabouraud dextrose agar with and without chloramphenicol and incubated at 37 0 C at room temperature for seven days. The plates were examined every other day for 7 days. Identification was based on macroscopic and microscopic morphology and physiological tests. Out of the 40 samples collected in this study, 37(92.5%) harboured potential pathogenic fungal agents.
Aspergillus species was the most encountered isolates 35(87.5%) while Rhizopus species was the least encountered 2(5.0%) isolate. Most of the Aspergillus species 23/35(65.7%) were from tiled floors while Rhizopus species 2(100%) were isolated from carpeted floors only. There was significant association between floor types and isolate distribution. Fungi were isolated from most of the locations in the study. There was no significant association between sample locations and isolates distribution (χ 2 = 4.0, p = 0.13). The dust samples from the offices harboured fungal species which are potential opportunistic mycosis agents.