Comparative Analysis of Airborne Microbial Concentrations in the Indoor Environment of Two Selected Clinical Laboratories

Abstract

The airborne microbial concentrations of two clinical Laboratories located in the main campus of Ahmadu Bello University (LBU) and Sarkin-pawa Street (LBS) in Samaru-Zaria town were investigated within a period in the dry season (January-march) and a period in wet season (July-September) 2007. Bacterial counts in the dry season ranged from 1.8 × 10 3 cfu/ml to 0.03 × 10 3 cfu/ml with the highest count in LBS in the third week of sampling while those of wet season ranged from 8.0 to 0.01 × 10 3 cfu/ml with the highest in LBS. The fungal count ranged from 3.6 to 0.08 × 10 3 cfu/ml in the dry season and 0.54 to 0.04 × 10 3 cfu/ml in the wet season. The highest fungal count occurred in LBS and LBU in dry and wet seasons respectively. There was no statistical difference between the bacterial concentrations of the laboratories using paired sample t-test. In fungal counts, there was also no significant difference between the laboratories. The correlation between the sum total of bacterial and fungal concentrations at 0.05 level of significance (2-tailed) using Kendall's tau_b, and Spearman's rho was significant. The predominant bacteria and fungi isolated from investigated air samples included Staphylococcus spp, Proteus spp, Streptococcus spp, Micrococcus spp, Aspergillus spp, Rhizopus spp, E. coli, Bacillus spp. This comparative information could be useful for the medical and public health practitioners on common airborne bacteria and fungi, and their roles in the indoor air quality of clinical laboratories.