Shaw, et al. (2018) say the operating room (OR) of the hospital is a special unit that requires a relatively clean environment. The microbial concentration of an indoor OR extrinsically influences surgical site infection rates. The aim of this study was to use active sampling methods to assess microbial colony counts in working ORs and to determine the factors affecting air contamination in a tertiary referral medical center.
This study was conducted in 28 operating rooms located in a 3000-bed medical center in northern Taiwan. The microbiologic air counts were measured using an impactor air sampler from May to August 2015. Information about the procedure-related operative characteristics and surgical environment (environmental- and personnel-related factors) characteristics was collected.
A total of 250 air samples were collected during surgical procedures. The overall mean number of bacterial colonies in the ORs was 78 ± 47 cfu/m3. The mean number of colonies was the highest for transplant surgery (123 ± 60 cfu/m3), followed by pediatric surgery (115 ± 30.3 cfu/m3). A total of 25 samples (10%) contained pathogens; Coagulase-negative staphylococcus (n = 12, 4.8%) was the most common pathogen. After controlling for potentially confounding factors by a multiple regression analysis, the surgical stage had the significantly highest correlation with bacterial counts (r = 0.346, p < 0.001). Otherwise, independent factors influencing bacterial counts were the type of surgery (29.85 cfu/m3, 95% CI 1.28–58.42, p = 0.041), site of procedure (20.19 cfu/m3, 95% CI 8.24–32.14, p = 0.001), number of indoor staff (4.93 cfu/m3, 95% CI 1.47–8.38, p = 0.005), surgical staging (36.5 cfu/m3, 95% CI 24.76–48.25, p < 0.001), and indoor air temperature (9.4 cfu/m3, 95% CI 1.61–17.18, p = 0.018).
Under the well-controlled ventilation system, the mean microbial colony counts obtained by active sampling in different working ORs were low, the researchers conclude. The number of personnel and their activities critically influence the microbe concentration in the air of the OR. They suggest that ORs doing complex surgeries with more surgical personnel present should increase the frequency of air exchanges. A well-controlled ventilation system and infection control procedures related to environmental and surgical procedures are of paramount importance for reducing microbial colonies in the air.
Source: Shaw LF, et al. Factors Influencing Microbial Colonies in the Air of Operating Rooms. BMC Infectious Diseases. 2018;18:4
Stay prepared and protected with Infection Control Today's newsletter, delivering essential updates, best practices, and expert insights for infection preventionists.
Reducing Hidden Risks: Why Sharps Injuries Still Go Unreported
July 18th 2025Despite being a well-known occupational hazard, sharps injuries continue to occur in health care facilities and are often underreported, underestimated, and inadequately addressed. A recent interview with sharps safety advocate Amanda Heitman, BSN, RN, CNOR, a perioperative educational consultant, reveals why change is overdue and what new tools and guidance can help.
The Next Frontier in Infection Control: AI-Driven Operating Rooms
Published: July 15th 2025 | Updated: July 15th 2025Discover how AI-powered sensors, smart surveillance, and advanced analytics are revolutionizing infection prevention in the OR. Herman DeBoard, PhD, discusses how these technologies safeguard sterile fields, reduce SSIs, and help hospitals balance operational efficiency with patient safety.
Back to Basics: Hospital Restores Catheter-Associated UTI Rates to Prepandemic Baseline
June 16th 2025A 758-bed quaternary medical center slashed catheter-associated urinary tract infections (CAUTIs) by 45% over 2 years, proving that disciplined adherence to fundamental prevention steps, not expensive add-ons, can reverse the pandemic-era spike in device-related harm.
Beyond the Surface: Tackling the Sterilization Challenges of Flexible Endoscopes
May 26th 2025Flexible endoscopes revolutionized modern medicine—but their complex design poses persistent sterilization challenges. With mounting infection risks and emerging innovations, experts are rethinking how to clean and safeguard one of health care’s most indispensable tools.