Abstract
Background
Environmental cleaning is an effective measure to prevent infections. However, performance observation has been rarely delineated. This study aimed to compare correlations among visual inspection, performance observation, and effectiveness by using adenosine triphosphate bioluminescence (ATP bioluminescence) as a comparator to find out which method is better to assess hospital cleanliness.
Methods
This prospective study was conducted at a medical center from April 2019 to October 2020. Seven high-touch surfaces were evaluated during and after terminal cleaning by performance observation, visual inspection, and ATP bioluminescence.
Results
The scores by performance observation, visual inspection, and ATP were 55.4%, 87.5%, and 26.6% after cleaning. The correlations between performance observation and visual inspection and between performance observation and ATP interpretation were weak positive (φ = 0.300, 0.324, P < .001). No correlation was between the visual inspection and ATP interpretation (φ=0.137). The median of ATP readings was lower in “compliant” group by performance observation and “clean” group by visual inspection than “not compliant” group and “not clean” group (P < .001).
Conclusions
Performance observation combined with ATP would be preferred to include to audit cleanliness on high-risk surfaces. Visual inspection would be a rapid and time-saving assessment tool on low-risk surfaces.
Background
Infections with multidrug-resistant organisms have become a critical issue across the world because of increased morbidity, mortality, and the financial burden of health care. The surfaces surrounding patients are usually contaminated by multidrug-resistant organisms and thereby increase the pressure of colonization and risk of infection.
1- Bonten M.J.M.
- Slaughter S.
- Ambergen A.W.
- Hayden M.K.
- Voorhis J.V.
- Nathan C.
The role of colonization pressure in the spread of vancomycin-resistant Enterococci.
Researches proved that healthcare associated infections were prevented by enhanced environmental cleaning. In Watson, Knelson and Li et al's studies, the infection rates of vancomycin-resistant
Enterococcus, methicillin-resistant
Staphylococcus aureus and multidrug-resistant
Acinetobacter baumannii decreased by 50%, 96%, and 62% after enforcement of environmental cleaning, respectively.
2- Watson P.A.
- Watson L.R.
- Torress-Cook A
Efficacy of a hospital-wide environmental cleaning protocol on hospital-acquired methicillin-resistant Staphylococcus aureus rates.
, 3- Knelson L.P.
- Williams D.A.
- Gergen M.F.
- Rutala W.A.
- Weber D.J.
- Sexton D.J.
A comparison of environmental contamination by patients infected or colonized with methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococci:a multicenter study.
, 4- Li Y.
- Ge H.
- Zhou H.
- Zhou W.
- Zheng J.
- Chen W.
Impact of environmental cleaning on the colonization and infection rates of multidrug-resistant Acinetobacter baumannii in patients within the intensive care unit in a tertiary hospital.
In a multicentre study involved 11 acute care hospitals found that vancomycin-resistant
enterococci infections decreased by 37% by introducing cleaning bundle.
5- Mitchell B.G.
- Hall L.
- White N.
- Barnett A.G.
- Halton K.
- Paterson D.L.
An environmental cleaning bundle and health-care-associated infections in hospitals (REACH): a multicentre, randomised trial.
Furthermore, according a system review, enhanced cleaning, and decontamination showed significant reductions in
Clostridioides difficile infection.
6Environmental cleaning and decontamination to prevent clostridioides difficile infection in health care settings:a systematic review.
There are several methods to evaluate the effectiveness of cleaning in hospital environment, including direct practice observation (performance observation), swab cultures, agar slide cultures, fluorescent markers, adenosine triphosphate bioluminescence (ATP bioluminescence), and visual inspection.
, 8- Mitchell B.G.
- Wilson F.
- Dancer S.J.
- McGregor A
Methods to evaluate environmental cleanliness in healthcare facilities.
ATP bioluminescence measures adenosine triphosphate (ATP) found in all animal, plant, bacterial, yeast, and mold cells. The luminometer measures generated light and reports results in relative light units (RLU). The higher the RLU number, the more ATP present, and the dirtier the surface.
Though audit and feedback by visual inspection is easy to implement and no devices are needed, visual inspection showed significantly different in results compared with the ATP bioluminescence and microbiologic sampling (aerobic colony counts). Microbial load cannot be visible so that the environmental cleanliness is usually overestimated when using visual inspection.
10- Mulvey D.
- Redding P.
- Robertson C
Finding a benchmark for monitoring hospital cleanliness.
, 11- Griffith C.J.
- Cooper R.A.
- Gilmore J.
- Davies C.
- Lewis M
An evaluation of hospital cleaning regimes and standards.
, 12- Huang Y.S.
- Chen Y.C.
- Chen M.L.
- Cheng A.
- Hung I.C.
- Wang J.T.
Comparing visual inspection, aerobic colony counts, and adenosine triphosphate bioluminescence assay for evaluating surface cleanliness at a medical center.
Compared with aerobic colony counts, ATP bioluminescence showed significantly different or poor and/or moderate correlation.
12- Huang Y.S.
- Chen Y.C.
- Chen M.L.
- Cheng A.
- Hung I.C.
- Wang J.T.
Comparing visual inspection, aerobic colony counts, and adenosine triphosphate bioluminescence assay for evaluating surface cleanliness at a medical center.
, 13- Nante N.
- Ceriale E.
- Messina G.
- Lenzi D.
- Manzi P
Effectiveness of ATP bioluminescence to assess hospital cleaning: a review.
Fluorescent marker method had the lowest clean rate compared with visual inspection, ATP bioluminescence, and microbiologic sampling.
14- Snyder G.M.
- Holyoak A.D.
- Leary K.E.
- Sullivan B.F.
- Davis R.B.
- Wright S.B
Effectiveness of visual inspection compared with non-microbiologic methods to determine the thoroughness of post-discharge cleaning.
, 15- Hung I.C.
- Chang H.Y.
- Cheng A.
- Chen A.C.
- Ting L.
- Chen M.W.
Application of a fluorescent marker with quantitative bioburden methods to assess cleanliness.
Housekeepers are expected to follow the standard of procedures to clean patient rooms, so it is essential to make sure that they do wipe to remove contaminants and disinfect the surfaces. However, the comparison of results between performance observation and ATP is rare. This study aimed to compare correlation between visual inspection and performance observations and effectiveness by using ATP bioluminescence test as a comparator in order to find out which method would be better to assess hospital cleanliness.
Results
The total of 504 samples were collected. The “clean” rate by visual inspection was 87.5%. The “compliant” rate by performance observation was 55.4%. The “pass” rate by ATP interpretation was 26.6%. The phi coefficient was 0.300 between the results of visual inspection and performance observation (
P < .001). The phi coefficient was 0.137 between the results of visual inspection and ATP interpretation (
P < .005). The phi coefficient was 0.324 between the results of performance observation and ATP interpretation (
P < .001). The “clean” rate was the highest and the “pass” rate was the lowest among the 3 methods. While the correlations were weak positive between visual inspection and performance observation and between performance observation and ATP interpretation, there was no correlation between visual inspection, and ATP interpretation (
Table 1).
Table 1Correlation between visual inspection, performance observation, and ATP interpretation.
ATP interpretationl, ATP readings less than 10 RLU (relative light unit, RLU) were interpreted “pass” :ATP readings more than 10 RLU (relative light unit, RLU) were interpreted “not pass”.
Among these high-touch surfaces in patient rooms, bed controls, bed rails and cart pull had “clean” rates more than 95%. However, the highest “compliant” rate was 67.3% for bed controls and the highest “pass” rate was only 36.5% for bed rails. Machine controls had the lowest “clean” rate 56.3%, Call buttons had the lowest “compliant” rate 31.3% and Tray tables had the lowest “pass” rate 20.0%. Most surfaces had no correlation or weak positive correlations between the results of any 2 methods except tray tables with medium positive correlation between visual inspection and ATP interpretation (φ = 0.429), machine controls and tray tables with medium positive correlation between performance observation and ATP interpretation (φ = 0.434, 0.509), call buttons with strong positive correlation between performance observation and ATP interpretation (φ = 0.856) (
Table 1).
The mean, median and the interquartile range of ATP readings for 504 samples were 138.39, 33.00, and 86.75 RLU. The most contaminated item was machine controls with the highest mean 297.92, median 73.00 and interquartile range 246; the least contaminated item was cart pulls with the lowest mean 54.25, median 20.00 and interquartile range 42. All means were much higher than medians indicated diverse contaminant levels among surfaces (
Table 2).
Table 2ATP readings (RLU) for selected surfaces.
The median of ATP readings by performance observation were 79.00 RLU for “not compliant” group and 14.00 RLU for “compliant” group (
P < .001), indicating that there was significant difference between the 2 groups of data. All high-touch surfaces but bed controls had significantly lower ATP readings in “compliant” group than “not compliant” group. The median of ATP readings by visual inspection were 158.00 RLU for “not clean” group and 26.00 RLU for “clean” group (
P < .001), indicating that there was significant difference between the 2 groups of data. Among these high-touch surfaces in patient rooms, bed rails, light switches, machine controls and tray tables also had significantly lower ATP readings in “clean” group than “not clean” group. The results showed that the surfaces which were cleaned and disinfected properly and free of dust, debris, and stains were cleaner than the opposite (
Table 3).
Table 3Comparing ATP readings (RLU) between “compliant” and “not compliant” by performance observation and between “clean” and “not clean” by visual inspection.
Discussion
Several literatures compared different methods to evaluate cleaning effectiveness. Overall, the highest clean rates were by visual inspection.
10- Mulvey D.
- Redding P.
- Robertson C
Finding a benchmark for monitoring hospital cleanliness.
, 11- Griffith C.J.
- Cooper R.A.
- Gilmore J.
- Davies C.
- Lewis M
An evaluation of hospital cleaning regimes and standards.
, 12- Huang Y.S.
- Chen Y.C.
- Chen M.L.
- Cheng A.
- Hung I.C.
- Wang J.T.
Comparing visual inspection, aerobic colony counts, and adenosine triphosphate bioluminescence assay for evaluating surface cleanliness at a medical center.
However, in Snyder et al's study, the highest clean rate was by microbiological method and the lowest clean rate was by fluorscent marker method.
14- Snyder G.M.
- Holyoak A.D.
- Leary K.E.
- Sullivan B.F.
- Davis R.B.
- Wright S.B
Effectiveness of visual inspection compared with non-microbiologic methods to determine the thoroughness of post-discharge cleaning.
Hung
et al. also found that the clean rate by fluorescent marker method was significantly lower than by microbiological method and ATP bioluminescence because residual gel on a surface could not be interpreted as the level of bioburden.
15- Hung I.C.
- Chang H.Y.
- Cheng A.
- Chen A.C.
- Ting L.
- Chen M.W.
Application of a fluorescent marker with quantitative bioburden methods to assess cleanliness.
In this study, “compliant,” “clean” and “pass” rates were 55.4%, 87.5, and 26.6% by performance observation, visual inspection and ATP interpretation with cutoff value 10 RLU, respectively. The highest rate was by visual inspection while the lowest rate was by ATP interpretation. There was no correlation between the results of visual inspection and ATP interpretation. We also found that clean rates by visual inspection tended to be overestimated compared to ATP interpretation and unassociated with each other.
10- Mulvey D.
- Redding P.
- Robertson C
Finding a benchmark for monitoring hospital cleanliness.
, 11- Griffith C.J.
- Cooper R.A.
- Gilmore J.
- Davies C.
- Lewis M
An evaluation of hospital cleaning regimes and standards.
, 12- Huang Y.S.
- Chen Y.C.
- Chen M.L.
- Cheng A.
- Hung I.C.
- Wang J.T.
Comparing visual inspection, aerobic colony counts, and adenosine triphosphate bioluminescence assay for evaluating surface cleanliness at a medical center.
That may result in regarding dirty surfaces as clean and spreading pathogens. The correlations between the results by visual inspection and performance observation and between performance observation and ATP interpretation were weak positive, indicating that the results of these 3 methods were not consistent and could not be inferred from each other. It may result from different contamination levels and wipe strength. Snyder et al also found that visual inspection, fluorescent marker, and ATP demonstrated poor correlation with microbiologic comparator and with each other.
14- Snyder G.M.
- Holyoak A.D.
- Leary K.E.
- Sullivan B.F.
- Davis R.B.
- Wright S.B
Effectiveness of visual inspection compared with non-microbiologic methods to determine the thoroughness of post-discharge cleaning.
We found that the ATP readings were significantly lower in “compliant” and “clean” groups than in “ not compliant” and “ not clean,” but the correlations between any 2 methods were poor. The key point was the cutoff value of ATP bioluminescence to define “clean.” There were authors who followed manufacturer instructions to set the cutoff values, for example, <5 RLU was considered clean for 3M Clean-Trace System, <10 RLU was considered clean for Hygiena ATP Monitoring Systems in this study.
,12- Huang Y.S.
- Chen Y.C.
- Chen M.L.
- Cheng A.
- Hung I.C.
- Wang J.T.
Comparing visual inspection, aerobic colony counts, and adenosine triphosphate bioluminescence assay for evaluating surface cleanliness at a medical center.
There were authors who followed prior studies, for example, <250 RLU or <500 RLU were considered clean for 3 M Clean-Trace NG Luminometer and 3M Clean-Trace System.
10- Mulvey D.
- Redding P.
- Robertson C
Finding a benchmark for monitoring hospital cleanliness.
,14- Snyder G.M.
- Holyoak A.D.
- Leary K.E.
- Sullivan B.F.
- Davis R.B.
- Wright S.B
Effectiveness of visual inspection compared with non-microbiologic methods to determine the thoroughness of post-discharge cleaning.
,15- Hung I.C.
- Chang H.Y.
- Cheng A.
- Chen A.C.
- Ting L.
- Chen M.W.
Application of a fluorescent marker with quantitative bioburden methods to assess cleanliness.
Several studies used microbiologic comparator, aerobic colony counts (ACC), to be the standard method to evaluate the effects of different methods in detecting cleanliness and showed no correlation, poor or moderate correlation between the ACC and ATP.
12- Huang Y.S.
- Chen Y.C.
- Chen M.L.
- Cheng A.
- Hung I.C.
- Wang J.T.
Comparing visual inspection, aerobic colony counts, and adenosine triphosphate bioluminescence assay for evaluating surface cleanliness at a medical center.
,13- Nante N.
- Ceriale E.
- Messina G.
- Lenzi D.
- Manzi P
Effectiveness of ATP bioluminescence to assess hospital cleaning: a review.
,19- Sanna T.
- Dallolio1 L.
- Raggi1 A.
- Mazzetti M.
- Lorusso1 G.
- Zanni A.
ATP bioluminescence assay for evaluating cleaning practices in operating theatres: applicability and limitations.
Many factors affect the ATP system, including bacteria species, colony counts, growth phase of bacteria, residual bleach solutions and material of environmental surfaces. The ATP system is relatively poor detection of gram-negative bacteria and in low colony counts less than 10
3- Knelson L.P.
- Williams D.A.
- Gergen M.F.
- Rutala W.A.
- Weber D.J.
- Sexton D.J.
A comparison of environmental contamination by patients infected or colonized with methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococci:a multicenter study.
colony-forming unit.
20- Turner D.E.
- Daugherity E.K.
- Altier C
Efficacy and limitations of an ATP-based monitoring system.
, 21- Shimoda T.
- Yano R.
- Nakamura S
ATP bioluminescence values are significantly different depending upon material surface properties of the sampling location in hospitals.
In Fattorini et al's reserch, fluorescent marker was compared with ACC and showed no correlations.
22- Fattorini M.
- Ceriale E.
- Nante N.
- Lenzi D.
- Manzi P.
- Basagni C.
Use of a fluorescent marker for assessing hospital bathroom cleanliness.
Besides, ATP can not only detect microbiological contaminants but also organic matter. That may explain why Sanna et al found that there was no correlation between ATP and total viable counts, but the 2 methods were consistent to identify the most contaminated areas.
19- Sanna T.
- Dallolio1 L.
- Raggi1 A.
- Mazzetti M.
- Lorusso1 G.
- Zanni A.
ATP bioluminescence assay for evaluating cleaning practices in operating theatres: applicability and limitations.
Results from the study, the highest mean ATP reading and the second lowest “compliant” rate were from the machine control panels. We found that most housekeepers were afraid to press any buttons accidentally and change the settings so that they did not wipe machine controls properly. The lowest mean ATP reading was from call buttons with the lowest “compliant” rate. That might be most patients were unconscious in the intensive care unit so housekeepers thought that the call buttons were not used.
Many studies tried to figure out which method was effective, rapid, and simple to assessment cleanliness. It would be better to give feedback to housekeepers on the spot. The results of performance observation have been rarely compared with other methods. However, the other methods, including visual inspection, ATP bioluminescence, aerobic colony counts and fluorescent marker, were often compared.
12- Huang Y.S.
- Chen Y.C.
- Chen M.L.
- Cheng A.
- Hung I.C.
- Wang J.T.
Comparing visual inspection, aerobic colony counts, and adenosine triphosphate bioluminescence assay for evaluating surface cleanliness at a medical center.
,13- Nante N.
- Ceriale E.
- Messina G.
- Lenzi D.
- Manzi P
Effectiveness of ATP bioluminescence to assess hospital cleaning: a review.
,15- Hung I.C.
- Chang H.Y.
- Cheng A.
- Chen A.C.
- Ting L.
- Chen M.W.
Application of a fluorescent marker with quantitative bioburden methods to assess cleanliness.
,22- Fattorini M.
- Ceriale E.
- Nante N.
- Lenzi D.
- Manzi P.
- Basagni C.
Use of a fluorescent marker for assessing hospital bathroom cleanliness.
Aerobic colony counts could quantify organism but it would be the most expensive, time-consuming method and needs to be executed by medical technician. ATP bioluminescence needs devices and training how to implement. Fluorescent marker is an indirect method to find out whether the surfaces are cleaned or not. Visual inspection would be the cheapest and easiest method. Studies indicated that the sensitivity of ATP was higher than visual inspection.
12- Huang Y.S.
- Chen Y.C.
- Chen M.L.
- Cheng A.
- Hung I.C.
- Wang J.T.
Comparing visual inspection, aerobic colony counts, and adenosine triphosphate bioluminescence assay for evaluating surface cleanliness at a medical center.
,14- Snyder G.M.
- Holyoak A.D.
- Leary K.E.
- Sullivan B.F.
- Davis R.B.
- Wright S.B
Effectiveness of visual inspection compared with non-microbiologic methods to determine the thoroughness of post-discharge cleaning.
The clean rates of visual inspection were significantly higher than ATP.
10- Mulvey D.
- Redding P.
- Robertson C
Finding a benchmark for monitoring hospital cleanliness.
, 11- Griffith C.J.
- Cooper R.A.
- Gilmore J.
- Davies C.
- Lewis M
An evaluation of hospital cleaning regimes and standards.
, 12- Huang Y.S.
- Chen Y.C.
- Chen M.L.
- Cheng A.
- Hung I.C.
- Wang J.T.
Comparing visual inspection, aerobic colony counts, and adenosine triphosphate bioluminescence assay for evaluating surface cleanliness at a medical center.
When the environment is visually clean, it would give people the first good impression. Griffith and Fattorini et al recommended that an integrated monitoring program or multistep process for assessing hospital cleanliness were needed.
8- Mitchell B.G.
- Wilson F.
- Dancer S.J.
- McGregor A
Methods to evaluate environmental cleanliness in healthcare facilities.
,22- Fattorini M.
- Ceriale E.
- Nante N.
- Lenzi D.
- Manzi P.
- Basagni C.
Use of a fluorescent marker for assessing hospital bathroom cleanliness.
That was using visual inspection or fluorescent markers first after appropriate cleaning. If surfaces are clean, using ATP bioluminescence in surfaces classified as high risk or critical surface.
8- Mitchell B.G.
- Wilson F.
- Dancer S.J.
- McGregor A
Methods to evaluate environmental cleanliness in healthcare facilities.
If ATP bioluminescence shows failure, surfaces need to be re-cleaned or detected by microbiological Methods.
22- Fattorini M.
- Ceriale E.
- Nante N.
- Lenzi D.
- Manzi P.
- Basagni C.
Use of a fluorescent marker for assessing hospital bathroom cleanliness.
There are several limitations in the study. First, there is no objective standard for visual inspection, especially which old and faded surfaces. It is hard to maintain consistency visually even though a single nurse was assigned to assess cleanliness. Second, we did not use aerobic colony counts to be the comparator because the ATP value may be affected by the first swab. Therefore, there was no golden standard to be compared. Third, the optimal benchmark needs to be tested. Fourth, the residual bleach solutions and material of environmental surfaces may interfere with ATP results.
20- Turner D.E.
- Daugherity E.K.
- Altier C
Efficacy and limitations of an ATP-based monitoring system.
, 21- Shimoda T.
- Yano R.
- Nakamura S
ATP bioluminescence values are significantly different depending upon material surface properties of the sampling location in hospitals.
Conclusion
In conclusion, we have found that there was no correlation between visual inspection and ATP. The correlations were weak positive between visual inspection and performance observation, and between performance observation and ATP. Although the ATP readings were lower in “compliant” and “clean” groups than in “not compliant” and “not clean,” the best cutoff value needs to be established in this hospital. Considering the effectiveness, we recommended that a combined program would be preferred to include performance observation first, then testing by ATP in surfaces classified as high risk. In surfaces classified as low risk, using Visual inspection would be a rapid, and timesaving assessment tool.
Article info
Publication history
Published online: July 24, 2021
Footnotes
Conflict of interest: None.
Copyright
© 2021 The Author(s). Published by Elsevier Inc. on behalf of Association for Professionals in Infection Control and Epidemiology, Inc.