BACTERIAL COLONY COUNTS DURING VAGINAL SURGERY

PJ Culligan, MD, MH Heit, MD, L Blackwell, RN, BS, CA Graham, MD, M Smith, MD, J Snyder, PhD

   Objective: To describe the bacterial types and colony counts present before and during typical benign vaginal surgery.

   Materials & Methods:  This was a descriptive study of patients undergoing vaginal hysterectomy with or without reconstructive pelvic surgery. Comprehensive aerobic and anaerobic bacterial cultures were obtained immediately before and throughout the surgical cases at pre-selected time intervals. Standard antimicrobial prophylaxis was administered in all cases. The endpoints were defined two ways. First, mean total colony counts and mean anaerobic colony counts were determined by adding all colonies regardless of bacteria type and then dividing by the number of patients in question at each time interval. Secondly, we labeled a vaginal field as ¡°contaminated¡± if bacterial colony counts were found to be ¡Ý 5000 colony forming units per mL at any given time interval.

   Results: 31 patients aged 26 to 82 years (average 51 ¡À 15) were included. Operative times ranged from 25 to 270 minutes (average 156 ¡À 61 minutes). The average body mass index was 29.3 ¡À 7.7. The highest total colony counts were found at the first intraoperative time interval (i.e. 30 minutes after completion of the surgical scrub). A similar trend occurred when only anaerobic bacteria were considered. On the first set of cultures (30 minutes after the surgical scrub), 52% (16 of 31) of the surgical fields were contaminated. At 90 minutes, 41% (12 of 29) were contaminated. A negligible amount of subsequent cultures were contaminated.

   Conclusions: The highest bacterial colony counts were found 30- 90 minutes after the surgical scrub. Therefore, any future interventions designed to minimize bacterial colony counts should focus on the first 30 to 90 minutes of surgery.

   Key Words: operative site infection, vaginal hysterectomy