Incidence of Microorganisms on Environmental Surfaces in Some Secondary Schools in Birnin Kebbi, Kebbi State, Nigeria

Due to the ubiquitous nature of bacteria and fungi, the microbiological analysis of environmental surfaces (chairs, tables, floors, hand rails, toilet door knobs and class door knobs) of five (5) secondary schools in Birnin Kebbi metropolis was carried out. Surface swabbing method was used for the collection of a representative sample on the surfaces. Media such as Nutrient agar, Eosin methylene blue, Sabouraud dextrose agar, and Mannitol salt agar were used for the isolation of the organisms. The total bacterial count ranged from 1.1×102 to 9.9×103 CFU/ml, while the total fungi count ranged from 0.0 to 3.6 ×103 CFU/ml. The bacteria isolated include: Corynebacterium kutsceri, Lactobacillus casei, Bacillus sphaerious, Staphlococcus aureus, Bacillus subtilis, Aeromonas spp, staphylococcus epidermidis, Pseudomonas spp, Micococcus varians, while the fungi isolated include Rhizopus stolonifer, Saccharyomyces cerevisae, Alternaria alternate, Aspergillus niger, Mucor spp., Fusarium spp.

The isolation of these organisms followed series of procedures, starting with samples collected with swab sticks emulsified with peptone water, followed by the sterile dilution of each sample to a factor of 10-1 for chairs, tables, hand rail and door knobs while floor was diluted to a factor of 10-2. One millilitre (1ml) aliquots of which was used as a representative sample used for isolation of pure colonies was followed by series of biochemical test to confirm the identification of each isolate. Despite the routine cleaning practiced in secondary school setting, isolation of microorganisms from secondary school setting is inevitable.