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ABSTRACT
The quality of air inside enclosed spaces like the classrooms where students spend a time nearly 7 to 8 hours daily while learning in school has become a matter of growing concern today. The aim of this study was to determine bacterial and fungal species associated with the indoor air of University of Benin, faculty of life Sciences lecture theatre and evaluate the antibiotic susceptibility profile of the bacterial isolates before and after curing. Prepared Nutrient and Potato Dextrose Agar plates were open in the various lecture theatres in faculty of Life Sciences, University of Benin, for about 15 min. They were incubated at 37 °C for 24 - 72 hr. Observed colonies were counted with a colony counter and the results per dilution count were recorded. Single colonies were identified and re-streaked as primary inoculants. Pure cultures were stored in Agar Slants. Antibiogram characterization was carried out for the bacterial isolates using the standard Kirby-Bauer disk diffusion methods. The multiple antibiotic resistance (MAR) index of the isolates were determined followed by curing experiment for all multidrug resistant isolates. The MAR index after curing was also determined immediately after a second antibiogram characterization. The highest bacteria load was recorded in Biochemistry Lecture Theatre (122.50±2.50 x 10 1 cfu/m3) while the least was recorded in Plant Biology and Biotechnology (PBB) Lecture Theatre (7.33±0.88 x 10 1 cfu/m3). The highest fungi load was recorded in Microbiology lecture theatre (14.50±0.50 x 10 1 cfu/m3) while the least was recorded in Plant Biology and Biotechnology (PBB) Lecture Theatre (2.00±0.00 x 10 1 cfu/m3). The bacterial isolates were Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus cereus. The fungi isolates were Aspergillus niger, Yeast, Mucor mucedo and Aspergillus flavus. The lecture theatre with the highest frequency of occurrence of bacteria was the Department of Microbiology Lecture Theatre (27.27 %). The highest occurring fungi was Aspergillus niger (55.56 %) while the least occurring were Mucor species and Aspergillus flavus (11.11 %). The highest frequency of occurrence of fungi was the department of Microbiology lecture Theatre (44.44 %) while similar the least percentage frequency of occurrence was reported in BCH, AEB and PBB lecture theatre (11.11 %). The highest percentage resistance was recorded on P. aeruginosa and B. cereus with multidrug resistance index of 0.4. The highest percentage resistance (100 %) was recorded were against ampiclox, zinacef and amoxacilin while complete sensitivity (0 %) was recorded against perfloxacin, gentamycin, ciprofloxacin, streptomycin and erythromycin. After curing, S. aureus and P. aeruginosa became susceptible to Rocephin with the highest MAR Index recorded only on B. cereus (0.4) while S. aureus and P. aeruginosa both showed an index of 0.3. The highest percentage resistance (100 %) was recorded were against ampiclox, zinacef and amoxacilin while complete sensitivity (0 %) was recorded against perfloxacin, gentamycin, rocephin, ciprofloxacin, streptomycin and erythromycin. The results obtained in this study clearly suggest that regardless of the time of the day, indoor environment allows aerosols build up which could serve as potential risk factors for spread of infections in the lecture theatres.
