May 14, 2026
Version 2
Microbiological Quality Assessment of Bathroom Towels Used By Students of a University in Ghana V.2
- Grace Semabia Kpeli1,
- Bismark Godzo1,
- Hubert Kwame Agbogli1,
- Priscilla Essandoh1,
- Counseller Nutifafa Livingstone1,
- Emmanuel Udochukwu Osisiogu2
- 1Department of Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana;
- 2Department of Science Laboratory Technology, Dr Hilla Limann Technical University, Wa, Ghana
- Grace Semabia Kpeli Research Workspace
Protocol Citation: Grace Semabia Kpeli, Bismark Godzo, Hubert Kwame Agbogli, Priscilla Essandoh, Counseller Nutifafa Livingstone, Emmanuel Udochukwu Osisiogu 2026. Microbiological Quality Assessment of Bathroom Towels Used By Students of a University in Ghana. protocols.io https://dx.doi.org/10.17504/protocols.io.81wgbjjrovpk/v2Version created by Grace Semabia Kpeli
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: May 13, 2026
Last Modified: May 14, 2026
Protocol Integer ID: 317017
Keywords: microbiological quality assessment of bathroom towel, microbiological quality of bathroom towel, microbiological quality assessment, microbiological quality, bathroom towel, swab sample collection from towel surface, bacterial isolate, towel surface, biochemical identification of bacterial isolate, swab sample collection, university students in ghana, positive organisms on blood agar, ghana this protocol, ghana
Abstract
This protocol describes a culture-based method for assessing the microbiological quality of bathroom towels. It covers swab sample collection from towel surfaces, serial dilution and total plate count enumeration on Plate Count Agar, and isolation and biochemical identification of bacterial isolates including Gram-negative organisms on selective and differential media and Gram-positive organisms on blood agar. The protocol was developed and applied in a cross-sectional study of bathroom towels used by university students in Ghana.
Materials
- Sterile swab sticks
- Phosphate-buffered saline (PBS), sterile
- Sample transport containers with ice
- Sterile test tubes
- Vortex mixer
- Serial dilution tubes
- Sterile Petri dishes
- Plate Count Agar (PCA), cooled molten (~45–50°C)
- Selenite F broth
- Brain Heart Infusion (BHI) broth
- MacConkey agar
- Blood agar
- Salmonella/Shigella (SS) agar
- Deoxycholate Citrate Agar (DCA)
- Refrigerated centrifuge
- Colony counter
- Incubator set to 37°C
- Biochemical identification reagents (indole, urease, citrate, glucose, lactose, H2S)
- Microscopy equipment
- Unique sample identifier labels
- Sterile pipettes and micropipettes (100 μL)
Ethical Considerations
This protocol was conducted under ethical clearance certificate UHAS-REC A.12 [21] 20-21.
The study objectives were explained to all participants and written informed consent was collected prior to enrolment. The study was conducted in accordance with the Declaration of Helsinki.
Questionnaire Data Collection
Administer a structured questionnaire to each participant to collect sociodemographic data and information on towel ownership, usage duration, washing frequency, drying practices, and hygiene behaviours. The questionnaire used in this study was administered via the Epicollect5 mobile application and is available at https://doi.org/10.5281/zenodo.20166054.
Swab Sample Collection
Label sterile swab sticks with a unique participant identifier prior to sample collection.
Moisten the sterile swab stick in sterile phosphate-buffered saline (PBS).
Swab the towel surface in a zig-zag manner, ensuring even coverage of the surface area.
Place the swab immediately into a labelled sterile tube.
Place the tube on ice in a sample transport container to minimize bacterial multiplication during transport.
Transport samples to the laboratory as soon as possible and process within 2 hours of collection.
Preparation of Bacterial Suspension and Serial Dilution
Transfer each swab stick into a test tube containing 5 mL of sterile PBS.
Vortex the tube thoroughly to dislodge all particles from the swab, producing a 10^-1 dilution (stock suspension).
Prepare serial dilutions from 10^-2 to 10^-5 using sterile PBS as the diluent by transferring 1 mL from each preceding tube into 9 mL PBS and vortexing between each transfer.
Total Plate Count (Pour Plate Method)
Label sterile Petri dishes to correspond to each dilution (10^-1 through 10^-5) for each sample.
Aseptically dispense 100 µL of each dilution into the corresponding labelled Petri dishes.
Pour 25 mL of cooled molten Plate Count Agar (~45–50°C) into each Petri dish.
Gently swirl the dish to mix the inoculum with the agar. Allow to solidify on a level surface.
Plate each dilution in duplicate to improve reliability of counts.
Invert plates and incubate at 37°C for 18–24 hours under aerobic conditions.
After incubation, count colonies using a colony counter. Record counts for plates yielding 30–300 colonies — these are considered countable.
For each sample, use the highest dilution within the 30–300 colony range to calculate bacterial load using the formula: CFU/mL = (Number of colonies × Dilution factor) / Volume plated (mL).
Exclude samples in which all plates yield counts greater than 300 (too numerous to count, TNTC) at all dilutions from quantitative analysis.
Log_10-transform CFU/mL values prior to statistical analysis to account for skewed distributions.
Isolation of Gram-Negative Organisms
Pellet the 10^-1 dilution by centrifuging at 11,000 rpm for 30 minutes in a refrigerated centrifuge.
Decant the supernatant carefully.
Using a sterile loop, inoculate a loopful of the sediment into Selenite F broth for selective enrichment of Salmonella spp. and Shigella spp.
Incubate the Selenite F broth at 37°C for 18–24 hours.
Sub-culture from the Selenite F broth onto Salmonella/Shigella (SS) agar and Deoxycholate Citrate Agar (DCA). Incubate at 37°C for 18–24 hours.
Inoculate a second loopful of the sediment into Brain Heart Infusion (BHI) broth. Incubate overnight at 37°C.
Sub-culture from BHI broth onto MacConkey agar for detection of Gram-negative organisms. Incubate at 37°C for 18–24 hours under aerobic conditions.
Where mixed growth is observed, perform purity plating by picking individual colonies and streaking onto fresh plates. Re-incubate at 37°C for 18–24 hours.
Isolation of Gram-Positive Organisms
Sub-culture from the BHI broth (Step 22) onto blood agar for detection of Gram-positive organisms.
Incubate at 37°C for 18–24 hours under aerobic conditions.
Where mixed growth is observed, perform purity plating as described in Section 30.
Bacterial Identification
Perform Gram staining on isolated colonies to confirm Gram reaction and cellular morphology.
Identify bacterial isolates using conventional biochemical tests appropriate to the organism type, including indole production, urease activity, citrate utilization, glucose fermentation, lactose fermentation, and H2S production.
Record organism identification based on the biochemical profile obtained.
Acknowledgements
Raw data from this study (pour plate counts, biochemical identification profiles, and questionnaire data) are available at https://doi.org/10.5281/zenodo.20162831. The questionnaire used in this study was administered via the Epicollect5 mobile application and is available at https://doi.org/10.5281/zenodo.20166054.
Notes:
- All incubations were performed at 37°C under aerobic conditions for 18–24 hours unless otherwise specified.
- Sample IDs follow the format: hostel code + participant number (e.g. ED001 = Edna Hostel, participant 001; AD = Alex Dey; 5S = Five-Star; DF = Defiat).