Antimicrobial susceptibility patterns of selected bacteria isolated from air conditioners in buildings in Kampala city
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This study was conducted to assess the bacterial quality of air conditioning units and indoor air of selected buildings in Kampala city. In addition, the antimicrobial susceptibility patterns of selected bacteria were determined. Forty air samples were collected using a high volume Staplex-TFIA air sampler and forty swab samples were also obtained from the air conditioner vents. Samples were analysed to determine bacterial load and identify the organisms using microbiology techniques including total plate count. The Antimicrobial resistance patterns of selected bacteria were determined using Kirby-Bauer disc diffusion method. Air samples in buildings in busy congested areas showed higher bacteria load than swab samples from corresponding air conditioners indicating high indoor air contamination by outdoor air and human activities. Swab and air samples from regularly serviced air conditioners had lower bacterial load than less regularly serviced air conditioners. Of the bacterial isolates recovered, the predominant bacterial species identified included; Bacillus sp. (30.6%), Staphylococcus aureus (22.9%), Micrococcus luteus (18.5%), Actinomycetes (10.8%), Streptococcus sp. (5.1%), Citrobacter sp. (2.5%), %), Buttiaxella gavinae (1.9%), E.coli (1.3%) Enterobacter sp. (1.3%), Bordetella parapertusis (0.6%) and Klebsiella rhinoscleromatis (0.6%). 5.7% of the isolated organisms were unidentified and classified as unknowns. On determining the antibiotic susceptibility patterns of selected bacteria, 35% of them were resistant to Sulphamethaxole-trimethoprim, 29% to ciprofloxacin, 47% to tetracycline, 9% to imipenem and 35% to ampicillin, while no resistance was observed to gentamicin and vancomycin. A significantly high Multiple drug resistance percentage (47%) was registered which led to the assumption that most of the tested organisms had prior exposure to the active agents in the drugs. The findings in this study underscore the importance of regular microbial air quality monitoring to limit exposure to potentially pathogenic bacteria present in air conditioners and indoor air.