Environmental microbiological surveillance of operation theatres in a tertiary care hospital

Microbial contamination of air/surfaces/articles in operation theatre (OT) is a major cause of surgical site and nosocomial infections. Approximately 10% of nosocomial infections have serious outcomes leading to longer duration of hospital stay and cost burden. Currently there is no uniform consensus on either the standards for surveillance, methodology for monitoring or the levels of acceptable contamination and the risk of nosocomial infections borne by OT. The present study was conducted with an aim to isolate and identify the microbial contamination of the air, surfaces and equipments of the OT of a tertiary care post graduate teaching hospital. Air quality surveillance of OT’s was done by settle plate method and note of bacterial CFU/ m3 count was made. For surface sampling, wet swabs were taken from different sites and equipments. Bacterial species were isolated and identified by conventional methods. In the settle plate technique, mean CFU/m3 was recorded for 8 different OT’s. Ophthalmology OT recorded least bacterial CFU rate of air(114 CFU/m3) followed by ENT OT(166 CFU/m3) and in Gynaecology and Obstretics OT(255CFU/m3), highest bacterial CFU rate was noted. Out of total 68 surface and articles sampled from different OTs, only 9(13.2%) showed growth of bacteria. The most common isolate was Coagulase negative Staphylococcus species (5.8%) followed by Bacillus and Klebsiella species (4.4%) each.