Routes of infection. A study of using "tracer particles" in the orthopedic operating room.

Wound irrigates and tissue samples were cultured from clean orthopedic wounds at the conclusion of 280 orthopedic operations. The surgeons used a laminar flow unit and took extra precautions against wound contamination although personnel exhaust systems were not used. It was possible to culture residual organisms but difficult to trace the source of these by bacteriological methods. Artificial or "tracer" particles which could be applied to patient or surgeon were retrieved from the wound and suitably stained. Using albumin microspheres it was possible to identify and differentiate "patient-derived particles" from "surgeon-derived particles" in the majority of all wounds. Contamination from the surgeon was significant even under near optimum operating room conditions. These techniques are useful for development of control measures for residual wound contamination in orthopedic operating rooms.