ABSTRACT
Atmospheric air, including indoor air, is a basic factor affecting the proper functioning of the human body. Air pollution constitutes one of the main threats to the environments in which people live. The Earth’s atmosphere is composed of gases and vapours of chemical compounds, acid rain, airborne ashes, dust, trace elements and biological contaminants. Biological air pollutants, also known as bioaerosols, include pollen, fungi, bacteria and viruses. The bacteriological quality of indoor air of commuter buses (University of Benin shuttle bus) was evaluated in this study. The samples used for this experiment were collected in triplicates. The following media were used; Nutrient agar, Meuller-Hilton agar, Triple sugar iron agar, Simmon citrate agar, Urea agar base, Mannitol salt agar, Bacillus cereus agar, Eosin methylene blue agar and Salmonella shigella agar. The cultural and morphological characteristics of discreet bacterial colonies were observed. The following biochemical tests were carried out; Catalase production test, Indole test, Oxidase test, Citrate utilization test, Urease production test and Sugar fermentation test (Triple Sugar Ion Agar Test). The result of the mean heterotrophic bacteria count of air samples from University of Benin shuttle buses revealed that the highest bacteria count of 2.422 ± 0.707×103 cfu/m3 was observed in a morning sample after the trip, closely followed by 2.409 ± 2.828×103 cfu/m3 observed before trip in the afternoon while the least bacteria count of 7.85×102 cfu/m3 was observed in the afternoon during the trip. The cultural, morphological and biochemical characteristics of bacteria isolates revealed that E. coli, Klebsiella sp., Shigella sp., Bacillus sp., Morganella sp., Enterococcus and Staphylococcus sp. were present in air samples. Bacillus sp. was the most prevalent organism with a percentage occurrence of 24.44%, Morganella sp. had a percentage occurrence of 20%,
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Klebsiella sp. had a percentage occurrence of 15.56%, Shigella sp. had an occurrence of 13.33%,
E. coli had an occurrence of 11.11%, Staphylococcus sp. had an occurrence of 8.89% and Enterococcus sp. was the least occurrent with a frequency of 6.67%. The antibiotics susceptibility pattern revealed that all bacteria isolates were resistant to vancomycin and metronidazole. Staphylococcus sp. was most resistant, being resistant to all antibiotics tested except Ertapenem and Ciprofloxacin. Bacillus sp. was susceptible to all antibiotics tested except Metronidazole, Gentamycin and Vancomycin.
