Bacterial Contamination of Indoor Air in Schools of Riyadh, Saudi Arabia

Abstract

Background: The presence of bacteria in the indoor air pose a serious problem from the point of view of health protection and environmental engineering. Precise determination of various groups of bacteria indoors is necessary for both to estimate the health hazard and to create standards for indoor air quality control. This is especially important in such densely populated facilities like educational institutions. Results: In the present study, 252 samples of indoor air and air conditioners of 25 schools (Middle Schools) Public and Special, those were collected from east and centre of Riyadh in, Saudi Arabia, between October and November 2015. The most common bacterial isolates were, Gram negative bacteria (Pseudomonas stutzeri, Francisella tularensis and Ralstonia mannitolilytica ) of the total airborne bacteria. Whereas, the prevailing Gram positive bacteria were the Staphylococcus aureus, followed by Kocuria kristinae. Also, Pseudomonas stutzeri was isolated from the air conditioners of special schools. Results revealed that the highest level of bacterial contamination was detected in the class rooms during lessons. Conclusions: High concentrations of bacteria was observed in the public schools (where overcrowded classrooms). Results obtained in this study showed that the bacterial species varied in their susceptibility to all the antimicrobials used. Majority of them showed resistance to one or more of antimicrobials compounds. It was observed that Ciprofloxacin was the most effective antibiotic to all bacterial species used during this study.