Multi-drug resistant bacteria, particularly Methicillin-resistant Staphylococcus
aureus (MRSA), Acinitobacter spp. and Escherichia coli are the main bacteria that cause
nosocomial infections in hospitals. There are several problems caused by nosocomial
infection, e.g. high mortality rate and treatment cost. Thus, this research focused on the
microbiological air quality, particularly the number of bacterial cells and multi-drug resistant
bacteria in air in various rooms using different air ventilation systems. The medical wards in
the Northern and the Southern wings use natural air ventilation, the intensive care unit (ICU),
respiratory care unit (RCU), immunology laboratory and office use mechanical air ventilation.
The immunology laboratory and office were used as control areas.