เทคนิคทางห้องปฏิบัติการเพื่อการตรวจติดตาม SARS-CoV-2 ในสิ่งแวดล้อมสำหรับการเฝ้าระวัง ป้องกัน และการควบคุมโรคในหน่วยบริการสุขภาพ

Chatchawan Sengthong; Chayanit Phutthanu; Watcharanan Chakchuai; Chanissara Junmuang; Kanchanaporn Uasuwat; Anut Ratreeprueg

Authors

Chatchawan Sengthong Institute for Urban Disease Control and Prevention, Department of Disease Control, Ministry of Public Health
Chayanit Phutthanu Department of Medical Technology and Clinical Pathology, Surin Hospital, Surin Province
Watcharanan Chakchuai Institute for Urban Disease Control and Prevention, Department of Disease Control, Ministry of Public Health
Chanissara Junmuang Institute for Urban Disease Control and Prevention, Department of Disease Control, Ministry of Public Health
Kanchanaporn Uasuwat Institute for Urban Disease Control and Prevention, Department of Disease Control, Ministry of Public Health
Anut Ratreeprueg Institute for Urban Disease Control and Prevention, Department of Disease Control, Ministry of Public Health

Keywords:

SARS-CoV-2, Dual-Swab Pooled Sampling, High-touch surfaces, Cycle threshold

Abstract

Environmental surveillance for SARS-CoV-2 contamination is a crucial strategy for preventing and controlling nosocomial infections. This study aimed to evaluate the effectiveness of two sampling techniques for detecting SARS-CoV-2 contamination: The Dual-Swab Pooled Sampling technique and the Individual Swab Sampling technique. Samples were collected frequently on high-touch surfaces such as door handles, handrails, faucets, and medical equipment within urban healthcare units. Samples were collected between August and October 2022. The samples were then examined in the laboratory for the Orf1ab, N, and E genes, detected by using Real-time RT-PCR combined with the Cycle Threshold (Ct) value.

The results found a total of 79 samples; the genetic sequence of the SARS-CoV-2 virus was detected in 4 samples (5.06%). The highest levels of viral contamination were found in the male’s restroom on the 1^stfloor, specifically on the door lock (Ct 32.82–34.50) and the spray handle (Ct 30.51–31.17). Additionally, genetic material of the SARS-CoV-2 virus was found on the female’s restroom sink faucet on floor 4, and the entrance door handle on floor 5. The efficiency of the Dual-Swab Pooled Sampling technique for high-touch surfaces achieved a sensitivity of 100% compared to the Individual Swab Sampling technique. The average difference in Ct values (ΔCt) between the two methods was 0.8 ± 0.3, with a p-value > 0.05, indicating no statistically significant difference. The study results indicate that the Dual-Swab Pooled Sampling technique is effective, preventing sample dilution even at low viral loads. Furthermore, it reduces laboratory workload by approximately 50% and can be applied to implement measures to prevent the spread of SARS-CoV-2 in the environment of healthcare units.

References

สถาบันรับรองคุณภาพสถานพยาบาล (องค์การมหาชน). มาตรฐานโรงพยาบาลและบริการสุขภาพ ฉบับที่ 5. พิมพ์ครั้งที่ 2. นนทบุรี: ก.การพิมพ์เทียนกวง; 2564. หน้า 147-51.

Paton S, Spencer A, Garratt I, Thompson KA, Dinesh I, Aranega-Bou P, et al. Persistence of severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) virus and viral RNA in relation to surface type and contamination concentration. Appl Environ Microbiol 2021; 87(14): e0052621. doi: 10.1128/aem.00526-21.

Zhou J, Otter JA, Price JR, Cimpeanu C, Meno Garcia D, Kinross J, Boshier PR, et al. Investigating severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) surface and air contamination in an acute healthcare setting during the peak of the Coronavirus Disease 2019 (COVID-19) pandemic in London. Clin Infect Dis 2021; 73(7): e1870–7. doi: 0.1093/cid/ciaa905.

Ye G, Lin H, Chen S, Wang S, Zeng Z, Wang W, et al. Environmental contamination of SARS-CoV-2 in healthcare premises. J Infect 2020; 81(2): e1-5. doi: 10.1016/j.jinf.2020.04.034.

Vicente VA, Lustosa BPR, Grisolia ME, Pavini Beato C, Balsanelli E, de Souza Gubert Fruet V, et al. Environmental detection of SARS-CoV-2 virus RNA in health facilities in Brazil and a systematic review on contamination sources. Int J Environ Res Public Health 2021; 18(7): 3824. doi: 10.3390/ijerph18073824.

Niyomdecha N, Noisumdaeng P, Archawametheekul P, Angkham S, Norapong B, Fungkrajai M, et al. Detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and bacteria on highly common contaminated surfaces at urban hospital and public areas. Nat Life Sci Commun 2023; 22(1): e2023010. doi: 10.12982/NLSC.2023.010.

Bansal A, Trieu MC, Eriksson EM, Zhou F, McVernon J, Brokstad KA, et al. SARS-CoV-2 infection rates and associated risk factors in healthcare workers: systematic review and meta-analysis. Sci Rep 2025; 15(1): 4705. doi: 10.1038/s41598-025-89472-5.

Santarpia JL, Rivera DN, Herrera VL, Morwitzer MJ, Creager HM, Santarpia GW, et al. Aerosol and surface contamination of SARS-CoV-2 observed in quarantine and isolation care. Sci Rep 2020; 10(1): 12732. doi: 10.1038/s41598-020-69286-3.

Prather KA, Marr LC, Schooley RT, McDiarmid MA, Wilson ME, Milton DK. Airborne transmission of SARS-CoV-2. Science 2020; 370(6514): 303-4. doi: 10.1126/science.abf0521.

Tiacharoen V, Denpetkul T, Kosoltanapiwat N, Maneekan P, Thippornchai N, Saeoueng A, et al. Detection of SARS-CoV-2 and variants in hospital wastewater in a developing country. Water 2022; 14(23): 3798. doi: 10.3390/w14233798.

Phumisantiphong U, Rupprom K, Wongsuk T, Manomaipiboon A, Maneerit J, Vimonvattana A, et al. Severe acute respiratory syndrome coronavirus 2 variants in patients with coronavirus disease 2019 and environmental sampling from the hospital and market during the coronavirus disease 2019 pandemic in Thailand. Diagn Microbiol Infect Dis 2025; 111(2): 116604. doi: 10.1016/j.diagmicrobio.2024.116604.

Rupprom K, Thongpanich Y, Sukkham W, Utrarachkij F, Kittigul L. Surveillance of norovirus, SARS-CoV-2, and bocavirus in air samples collected from a tertiary care hospital in Thailand. Sci rep 2024; 14(1): 22240. doi: 10.1038/s41598-024-73369-w.

Kampf G, Pfaender S, Goldman E, Steinmann E. SARS-CoV-2 detection rates from surface samples do not implicate public surfaces as relevant sources for transmission. Hygiene 2021; 1(1): 24-40. doi:10.3390/hygiene1010003.

Mondelli MU, Colaneri M, Seminari EM, Baldanti F, Bruno R. Low risk of SARS-CoV-2 transmission by fomites in real-life conditions. Lancet Infect Dis 2021; 21(5): e112. doi: 10.1016/S1473-3099(20)30678-2.

Peccia J, Zulli A, Brackney DE, Grubaugh ND, Kaplan EH, Casanovas-Massana A, et al. Measurement of SARS-CoV-2 RNA in wastewater tracks community infection dynamics. Nat Biotechnol 2020; 38(10): 1164-7. doi: 10.1038/s41587-020-0684-z.

World Health Organization. Surface sampling of coronavirus disease (COVID-19): a practical “how to” protocol for health care and public health professionals [Internet]. 2020 [cited 2025 Nov 12]. Available form: https://www.who.int/publications/i/item/surface-sampling-of-coronavirus-disease-(-covid-19)-a-practical-how-to-protocol-for-health-care-and-public-health-professionals.

นัตฏิยา ศรีสุราช, ศศิประภา วัฒนวิเศษ, พรรณิชา วงศ์สายเชื้อ. ประเมินการตรวจหาเชื้อ SARS-CoV-2 จากตัวอย่างรวม ด้วยวิธี Real time RT-PCR ในจังหวัดขอนแก่น. วารสารเทคนิคการแพทย์ 2564; 49(3): 7909-21.

Abrahão JS, Sacchetto L, Rezende IM, Rodrigues RAL, Crispim APC, Moura C, et al. Detection of SARS-CoV-2 RNA on public surfaces in a densely populated urban area of Brazil: A potential tool for monitoring the circulation of infected patients. Sci Total Environ 2021; 766: 142645. doi: 10.1016/j.scitotenv.2020.142645.

Ye G, Lin H, Chen S, Wang S, Zeng Z, Wang W, et al. Environmental contamination of SARS-CoV-2 in healthcare premises. J Infect 2020; 81(2): e1–5. doi: 10.1016/j.jinf.2020.04.034.

Kim UJ, Lee SY, Lee JY, Lee A, Kim SE, Choi OJ, et al. Air and environmental contamination caused by COVID-19 patients: a multi-center study. J Korean Med Sci 2020; 35(37): e332. doi: 10.3346/jkms.2020.35.e332.

Amoah ID, Pillay L, Deepnarian N, Awolusi O, Pillay K, Ramlal P, et al. Detection of SARS-CoV-2 RNA on contact surfaces within shared sanitation facilities. Int J Hyg Environ Health 2021; 236: 113807. doi: 10.1016/j.ijheh.2021.113807.