Environmental air and airborne infections

The results of a study on the epidemiology of airborne (aerobic) surgical infections are presented. The first phase of the study was carried out in a surgical suite which contained no environmental or traffic control systems. The second phase of the study took place within a modern "up to date" operating room suite containing multiple air screens as well as an elaborate ventilation system utilizing HEPA type filters which provided the operating room with clinically sterile air. One hundred and fifty-six patients were also studied. All patients underwent major procedures. The ratio of clean, clean-contaminated, and dirty cases was the same in both groups. Preoperatively, a nasal swab, clean voided urine (or vaginal swab) and a rectal swab were obtained on each patient. Daily nasal cultures and cultures of suspected sites of infection were obtained postoperatively. Daily nasal cultures and "glove sweat" cultures were obtained on all personnel attending the patient. Environmental cultures of the operating room, the operating room hallway, recovery room and patients' rooms were also taken. All samples were checked for the presence of staphylococci, streptococci, Escherichia coli, proteus species, enterobacter, klebsiella, and pseudomonas. In all, 15,000 cultures were taken during the study. The rate of infection was essentially the same in both phases of the study. Environmental air only occasionaly served as the source of infecting organisms. The results of the study support the conclusion that the most common source of infecting organisms in surgical infections is thepatient or those around him. The most common time of contamination is during the surgical procedure itself. Surgical infections can best be minimized by meticulous observation of fundamental principles of antisepsis rather than by dependence on elaborate and costly ventilation and air control systems.