Introduction. One method of surgical site infection prevention is lowering intraoperative environmental contamination. We sought to evaluate our hospitals operating room (OR) contamination rates and compare it to the remainder of the hospital. We tested environmental contamination in preoperative, intraoperative and postoperative settings of a total joint arthroplasty patient. Materials & Methods. 190 air settle plates composed of trypsin soy agar (TSA) were placed in 19 settings within our hospital. Locations included the OR with light and heavy traffic, with and without masks, jackets, and shoe covers, sub-sterile rooms, OR hallways, sterile equipment processing center, preoperative areas, post-anesthesia care units, orthopaedic floors, emergency department, OR locker rooms and restrooms, a standard house in the local community, and controls. The plates were incubated in 36 degrees celsius for 48 hours and colony counts were recorded. Numbers were averaged over each individual area. Results. The highest CFU was the OR locker room at 28 CFU/plate/hr. Preoperative & post anesthesia care unit holding areas were 7.4 CFU & 9.6 CFU, respectively. The main orthopaedic surgical ward had 10.0 CFU/plate/hr, while the VIP hospital ward had 17.0 CFU/plate/hr. The OR environment all had low CFUs. A live OR had slightly higher CFUs than ones without OR personnel. The OR sub-sterile room had 5.2 CFU/plate/hr, and the OR hallway had 11.2 CFU/plate/hr. The local community household measured 5.6CFU/plate/hr. Discussion. In comparison to the local community household, the OR locker room, restrooms, hospital orthopaedic wards, ED, pre-operative holding, PACU and OR hallway all had higher
