Decreasing Operating Room Environmental Pathogen Contamination Through Improved Cleaning Practice

L. Silvia Munoz-Price, MD; David J. Birnbach, MD, MPH; David A. Lubarsky, MD, MBA; Kristopher L. Arheart, EdD; Yovanit Fajardo-Aquino, MD; Mara Rosalsky, RN; Timothy Cleary, PhD; Dennise DePascale, MT; Gabriel Coro, MD; Nicholas Namias, MD; Philip Carling, MD


Infect Control Hosp Epidemiol. 2012;33(9):897-904. 

In This Article


This project was initially implemented to evaluate the possible role of the operating room environment in the horizontal transmission of A. baumannii in our hospital. After confirming episodic surface contamination with this organism, we implemented an evaluation of the thoroughness of cleaning in our operating room areas. Using the results of both fluorescent marking and environmental culture, we developed a structured education and feedback program. This program facilitated improvement of the cleaning process, similar to previously described programs that were implemented for areas other than operating rooms.[11] At baseline, we found that less than 50% of tested surfaces had been cleaned by 24 hours after target application. Ongoing performance feedback over the next 4 months led to an 82% increase in the cleaning of markers by the final month of follow-up. The significant improvement in cleaning of anesthesia equipment was most likely attributable to the subsequent reassignment of cleaning duties, similar to an intervention previously reported by Baille.[16]

An evaluation of the thoroughness of floor cleaning was included in the study, because earlier observations by our group disclosed the fact that objects that fall onto the floors are frequently placed back either on horizontal work surfaces or on patients themselves. For example, intravenous tubing frequently contacts the floor as it drapes between the patient and the intravenous pump (Figure 2). Anesthesia providers have frequent and multiple contacts with such objects, including intravenous tubing, mixture controls, and intravenous administration hubs as well as with patients and horizontal surfaces. Consequently, the operating room floor can potentially transmit organisms to the patient through inadvertent contamination of surfaces during routine care.

Figure 2.

Interactions between objects and operating room floors. A, Strap used to fasten a patient to the operating room bed is shown draping over the floor. B, Intravenous tubing and other leads are shown curling on the operating room floor.

During the intervention, we observed decreased contamination of surfaces by gram-negative bacilli. The prevalence of contamination with S. aureus, Enterococcus species, or skin flora failed to show a significant change, possibly because of the relative paucity of cultures positive for the former 2 organisms at any point in the study. The ubiquitous nature of coagulase-negative Staphylococcus species, ongoing contamination of surfaces because of transient hand colonization of healthcare workers, or contaminated circulating air may have limited our ability to evaluate the impact of the interventions on skin organisms.

Other studies have documented similar improvement in bacterial contamination of surfaces in response to improved thoroughness of disinfection. Hayden and colleagues studied the impact of covert cleaning observations on contamination of the environment by VRE.[1] The authors found that a 75% improvement in the thoroughness of cleaning was associated with a 73% (P = .0001) decrease in near-patient environmental contamination with VRE.[1] Likewise, Goodman and collaborators used a fluorescent monitoring and feedback program in 10 intensive care units within a single hospital.[17] In their study, an 80% improvement in the thoroughness of cleaning was associated with a 61% (P = .02) decrease in environmental contamination with MRSA and VRE.[17] In our study, although an 87% improvement in cleaning thoroughness was associated with a concomitant 80% decrease in environmental contamination by gram-negative bacilli, we were unable to document a clearly significant decrease in S. aureus or enterococcal environmental contamination, possibly for the reasons noted above. Because of the likelihood of ongoing intestinal flora contamination of the operating room environment by patients, we believe that it is likely that the decreased contamination by gram-negative bacilli occurred as a result of improved thoroughness of surface cleaning.

Several limitations of our study should be noted. Because of scheduling and infection control staff limitations, cultures and evaluation of cleaning thoroughness were performed on alternate weeks. Although this limitation could have theoretically blunted the magnitude of our findings, the impact of this limitation would be expected to be equal before and after the improvement in cleaning thoroughness. Although we observed substantial improvement in the degree of contamination with gram-negative bacilli, the manner in which the study was performed may have prevented an accurate assessment of the impact of our intervention on other organisms. Although additional studies may clarify the relevance of this limitation, the fact that we documented an 80% decrease in environmental contamination by gram-negative organisms during a time in which the thoroughness of environmental cleaning improved to 82% is similar to the studies previously cited. The sensitivity of our analysis might also have been impacted by an underestimation of the bioburden associated with the small surfaces of the switches and monitors of the anesthesia machines. Additionally, culture results were analyzed as dichotomous rather than continuous variables, which potentially limited the sensitivity of our evaluation. Although future studies may wish to incorporate quantitative cultures, the generally very low bioburden of environmental surfaces in healthcare settings might limit the sensitivity of the analysis to detect bioburden changes after interventions without evaluating a very large number of surfaces. Although the fact that chemical neutralizers were not used could have potentially blunted the sensitivity of our analysis, such an impact would have been constant throughout the study. Finally, it is important to note that our findings relate to a fairly brief study in a single institution.

The finding that only 74% of surfaces harbored viable organisms before the intervention is similar to observations made by others who have found 31%–95% of random healthcare surfaces other than floors to either be sterile or to harbor <2.5 aerobic bacterial colonies per centimeter.[2,18,19] Because of our findings, we would agree with others who have noted that failure to take into account the level of cleanliness of surfaces before cleaning may lead to an overestimation of the efficacy of cleaning protocols when using culture-based or adenosine triphosphate evaluation systems to study the thoroughness of cleaning practices.[20]

Education combined with objective feedback using UV markers has previously been shown to improve the thoroughness of environmental cleaning in a range of healthcare settings, including general medical wards, intensive care units, operating room, and emergency medical vehicles.[10,11,21,22] During these studies, improvement was accomplished exclusively through ongoing objective performance feedback to the environmental services staff. Although the sustainability of improved hygienic practice needs to be evaluated more extensively,[23] preliminary findings suggest that the impact of such programs may deteriorate once feedback is no longer ongoing.[24,25] The only study to date that objectively evaluated the thoroughness of terminal room cleaning in the operating room setting showed that only 25% of high-touch surfaces were cleaned according to policy.[10] A possible explanation for the difference between our finding (47% thoroughness of cleaning at baseline) and the findings of Jefferson et al[10] might be the fact that environmental culture results were provided to the staff on a single occasion before baseline fluorescent marker evaluation was initiated, whereas the evaluations reported by Jefferson et al[10] were performed covertly.

Based on our findings and existing literature,[10,12,13] operating rooms might not be the clean settings that healthcare providers commonly believe them to be. Related findings within operating rooms have been recently described by Loftus and colleagues.[12,13] They described bacterial transmission from patients to the environment in 89% of instances.[12] These findings illustrate the fact that interactions between patient body surfaces, hands, and the operating room environment play an important role in the transmission of bacteria. In their studies, these authors described transmission of organisms to intravenous stopcocks in 11.5% of patients, with approximately half of these cases associated with the anesthesia providers.[13] Nevertheless, studies have yet to be performed that systematically evaluate the potential for relatively more contaminated operating room surfaces leading to greater rates of hospital-acquired infection. During 2011, our hospital observed a decreased number of acquisitions of carbapenem-resistant A. baumannii (especially in our surgical units) as well as a reduced rate of neurosurgical wound infections (data not shown). However, many other interventions aimed at decreasing the same outcomes were implemented concomitantly. Therefore, we are unable to quantify the independent impact of our program on these infections.

In conclusion, this study demonstrated for the first time, to our knowledge, that simple programmatic improvement in the thoroughness of disinfection cleaning in the operating room area can significantly decrease surface contamination with gram-negative organisms that have the potential for transmission to patients and healthcare workers. Because of the recent finding that subsequent occupants of an intensive care unit room have a substantial risk of acquiring either Pseudomonas or Acinetobacter species from previous occupants of the room,[26] our results suggest that additional studies may be warranted to clarify the environmental epidemiology and risks related to the possible transmission of surface-contaminating pathogens from operating room surfaces that have not been properly cleaned. Furthermore, studies have yet to be performed to objectively quantify the risk associated with environmental cleaning practices that are not in accordance with current AORN recommendations.[15] However, our findings and those of Jefferson et al[10] suggest that there may be a need to more thoroughly evaluate both process and outcome issues related to the role of the operating room environment in pathogen transmission.