BackGround: Microbiological air contamination in operation theatres (OTs) and labor rooms (LRs) is a major risk factor for surgical site infection. Routine monitoring in vulnerable areas such as OTs and LRs should always be performed as part of infection control to evaluate the contamination by microorganisms and monitor for the presence of nosocomial agents.
Material & Methods: The research was performed in Microbiology Department, India between November 2017 and November 2020 for a period of 3 years. Upon  adequate sterilization and disinfection of the OTsand Labour room , samples were taken. Surface swabbing and settle plate technique were two sampling techniques used in the analysis. A total of 3492 surface samples were obtained from 5 OTs and LR sites and equipment. Sterile swabs soaked in nutrient broth were rolled over to the surface of equipment All the samples were carefully marked and transferred to  laboratory and incubated at 37°C for 4h. Swabs taken from different sites were streaked on to 5% sheep Blood agar and Mac Conkey agar plates (Himedia company Limited) incubated at 37°C for 24 h under aerobic conditions. A total of 648 air samples were A total of 648 air samples were collected. Media-containing plates are exposed to the atmosphere face-up to collect gravity-settling particles. the number of colonies per plate was counted using Omeliansky's formula
Results: Out of 3492 surface swabs 294 samples (8.42%) showed growth taken from 5 OTs and LR.  Bacillus spp. 212 (72.11%) was the highest number and least number was from Pseudomonas spp. 6 (2.04%).Through air sampling methods, 677 CFU/m3 was reported from general surgery. The microbial species isolated were CoNS, Bacillus spp. and Aspergillus niger.
Conclusion: Regular microbiological surveillance of OT is essential to detect and control contamination.
Keywords: Operation theatre, Labour room, Microbiological surveillance, India