Background: Contamination indicated by air microbiological concentration in the operating theatre is a major risk factor for causing surgical site infection (SSI) and other nosocomial infections.
Research purpose:The propose of this study was to determine when to perform routine sterilization after renovation of the operating theatres by analyzing air microbiological concentrations. Methods: This research was a cross sectional study, comparing air microbiological concentrations between HVAC (heating, ventilation and air conditioning) system with or without heater, that were analyzed descriptively using STATA14. The concentrations of air microbiology were checked every two weeks by the