ADVANCEMENT OF THE SCIENCE
The guest traffic area in our study is defined as the area where the guest is likely to interact with high-touch surfaces while moving around the room during their stay. The bed area fo- cuses on high-touch surfaces that the guest is likely to interact with at arm’s length from the bed. The bathroom area centers around high- touch surfaces that typically are found in bath- rooms of midscale lodging properties. To determine the list of high-touch surfaces, publicly available information was gathered from websites of leading hotel brands (Hil- ton, 2021; IHG, 2021; Marriott, 2021; Wyn- dham Hotels, 2021) that have implemented ECPs and the cleaning companies they have partnered with (Ecolab, 2021; Reckitt, 2021) and information gathered from health organi- zations (CDC, 2024a; WHO, 2021) that have identified high-touch surfaces in various set- tings. Additionally, the American Automobile Association (AAA, 2021) has implemented the Inspected Clean Program that is used when evaluating their Diamond Rating of ho- tels and specifies the surfaces that have been included in this list. Before the start of the sample collection, each standard guest room was visually in- spected to confirm all of the established sur- faces were present in the room and to identify where the sampling would occur. We deter- mined that all 37 surfaces were present in the room. Many of the surfaces in the hotel room had two of the same surfaces (e.g., two lamps, two nightstands, two closet handles), for which one was designated for the ATP meter measurement and the other was used to collect microbial samples. For surfaces that had only one surface to sample, the surface area was large enough that it could be eas- ily divided to allow for a 5 × 5 cm 2 sampling area for both the ATP meter and the microbial samples. Environmental sampling took place at the beginning of July 2021 and continued until the end of January 2022. A total of 740 microbial samples and 740 ATP meter read- ings were collected from high-touch surfaces in hotel rooms. Additionally, a hygrometer was taken into the hotel rooms and recorded an average room temperature of 68.8 °F and an average relative humidity of 55%. Laboratory Preparation Aluminum foil was cut into 5 × 5 cm 2 tem- plates to control for the surface area that was swabbed during the sample collection
process. Test tubes (37 for each surface) containing 9 mL of 1% peptone water (PW; Difco) were prepared before each sampling event to collect samples from high-touch surfaces before and after cleaning for each room sampled in our study. To control for any residual sanitizers that could be present during the sample collection, 0.9 ml (10%) of Dey-Engley Neutralizing Broth was added to each sample collection tube that was used to collect samples after the room was cleaned. All materials were sterilized by autoclave at 15 lb (7 kg) of pressure (121 °C) for 15 min. Sample Collection For the bacterial profile, each surface was swabbed aseptically before the room was cleaned using sterile cotton-tipped plastic swabs moistened with PW in a 5 × 5 cm 2 area on each surface. Sterile 5 × 5 cm 2 aluminum foil templates were used to control for vari- ability in surface area sampling sizes. After the sampling of each surface, the untouched ends of the cotton-tipped plastic swabs were broken off to prevent possible contamination and placed in sterile test tubes containing 9 ml of PW. Samples were then placed in a por- table cooler with ice (<10 °C) and transferred to a microbiology laboratory for analysis. Following the hotel room cleaning, sam- pling was conducted again 1 hr after the room was cleaned to allow an adequate amount of time for cleaners and surface sanitizers to air- dry. As an added control, a neutralizing agent was added to the sample collection tubes to negate the effect of any residual sanitizers on sampled surfaces. For sampling conducted with the ATP me- ter, surfaces were swabbed to determine if the presence of ATP was detected. Sterile tem- plates were placed on surfaces in the room and swabbed using the Hygiena UltraSnap Surface Swabs per manufacturer instructions. Results from each sample were generated in real time within 15 s and recorded for each surface before and after cleaning. The ATP meter was recalibrated per manufacturer in- structions prior to each sampling event. A to- tal of 10 rooms were sampled over 6 months from July 2021 to January 2022.
laboratory for microbiological analysis. Next, 10-fold serial dilutions were made by pass- ing 1 ml of each collected sample into a test tube containing 9 ml of PW. Then 1 ml from each dilution (3 dilutions) was placed onto the appropriate 3M Petrifilm Plates to quan- tify APCs, E. coli /coliforms, and S. aureus for each sample and the plates were incubated at 37 °C for 24–48 hr. The total viable count was determined based on the distinct color of the microorganisms on each of the plates. Micro- bial colonies were manually counted using a Quebec colony counter to quantify the presence of aerobic bacterial contamination, generic E. coli and coliforms, and S. aureus as indicators of microbial contamination for each surface. Bacterial counts were converted by using the log formula in Microsoft Excel before the statistical analysis. The data from the 10 rooms were then transferred into IBM SPSS Statistics version 28 and the mean log CFU/ cm 2 and RLU/cm 2 were compared using a paired samples t -test to determine if there were statistically significant differences (p < .05) based on the microorganism and area of the hotel room.
Results
Sample Analysis Before and After Cleaning
The 37 sampled high-touch surfaces were divided into the guest traffic area, bed area, and bathroom area; surfaces were further grouped by the log CFU/cm 2 for APCs, E. coli /coliform counts, S. aureus , and RLU/cm 2 from the ATP meter readings for analysis. A paired samples t -test (95% confidence inter- vals) was conducted to determine if there were statistically significant differences in the samples taken before and after the hotel rooms were cleaned. In general, S. aureus counts decreased in each of the three areas on all high-touch sur- faces sampled in the hotel room. Over the course of our study, E. coli was not detected in any of the guest rooms. Coliform counts, however, increased in all three of the sampled areas on all high-touch surfaces, except for the closet handle, drapery pull handle, and shower floor. For the APCs, a majority of the high-touch surfaces included in the guest traffic area increased after the room was cleaned, whereas all surfaces in the bed area
Microbiological and Statistical Analysis
After the surface samples were collected, they were transported to a Biosafety Level 2
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Volume 87 • Number 7
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