Microbiological Surveillance of Operation Theatres: Five Year Retrospective Analysis from a Tertiary Care Hospital in North India.

INTRODUCTION: Microbiological contamination of air and environment in the operation theaters (OTs) are major risk factor for surgical site and other hospital-associated infections.

OBJECTIVES: The aim was to identify bacterial colonization of surfaces and equipment and to determine the microbial contamination of air in the OTs of a tertiary care hospital.

MATERIALS AND METHODS: Five years (January 2010-December 2014) retrospective analysis of the data obtained from routine microbiological surveillance of the five OTs of the hospital was done. Surface samples were taken with wet swabs from different sites and equipment. Bacterial species were isolated and identified by conventional methods. Air quality surveillance of OTs was done by settle plate method.

RESULTS: A total of 4387 samples were collected from surfaces and articles of various OTs. Out of these only 195 (4.4%), samples showed bacterial growth and yielded 210 isolates. The predominant species isolated was Bacillus with 184 (87.6%) isolates followed by coagulase-negative Staphylococcus 17 (8.1%), Staphylococcus aureus 6 (2.9%), and Enteroccoccus spp. 3 (1.4%). Analysis of the OT air samples showed least colony forming unit (cfu) rate of air (27 cfu/m(3)) in ophthalmology OT and highest rate of 133 cfu/m(3) in general surgery OT.

CONCLUSION: The study shows that OTs of our hospital showed a very low bacterial contamination rate on surface swabbing and a cfu count per m(3) of air well within permissible limits.