Airborne bacterial contamination of operative wounds.

Both the numbers and species of airborne bacteria were studied during 263 surgical procedures. The numbers of bacteria isolated were reduced by 95 percent in a horizontal laminar flow room compared with a conventional room and a further 4 percent reduction occurred when a suction-mask system was used. The species of bacteria isolated differed notably at the operative site where a slit sampler was used, as compared with the instrument table and the periphery of the room where settling plates were used. Studies done during simulated surgical operation suggested that light fixtures, pass-through doors, floor contamination and the draped patient were not important sources of airborne contamination in this horizontal laminar flow system. The exact role of airborne bacterial contamination of operative wounds in the development of clinical wound infections is still unknown. Therefore, installation of laminar flow systems must be considered unnecessary at this time.