Predicting bacterial populations based on airborne particulates: a study performed in nonlaminar flow operating rooms during joint arthroplasty surgery.

BACKGROUND Prevention of postsurgical infection is preferable to treatment. Prevention requires identification and control of the potential sources of microbial contamination. This study investigated whether the density of airborne particulates can predict the density of viable airborne bacteria at the surgery site. METHODS A standard particle analyzer was used to measure the number and diameter of airborne particulates during 22 joint arthroplasty surgeries. An impact air sampler and standard culture plates were used to identify and count colony-forming units (CFU). RESULTS Particulate density averaged >500,000 particles/m(3) per 10-minute interval, and 1786 CFU were identified, primarily gram-positive cocci. A particle density > or = 10 microm explained 41% of the variation in CFU density. Particle and CFU density increased with longer surgery duration and higher staff counts. CONCLUSIONS These findings support the use of environmental controls that isolate and protect the surgical site from airborne particulates and contamination.