Background: Sterilization and Disinfection of Medical Instruments and Devices in Healthcare

Millions of surgical procedures and medical evaluations of internal body cavities using endoscopes or ultrasound probes occur worldwide each year. Each of these procedures involves contact by a medical device or surgical instrument with a patient’s sterile tissue and/or mucous membranes. A major risk of all such procedures is the introduction of infection. Failure to properly disinfect or sterilize medical devices and surgical instruments may lead to transmission via these devices (e.g., contaminated endocavity ultrasound probes could transmit human papillomavirus {HPC}).¹ Therefore, achieving disinfection and sterilization by disinfectants and sterilization practices is essential for ensuring that medical and surgical instruments do not transmit infectious pathogens to patients.  

Over 50 years ago, Earle H. Spaulding devised a rational approach to disinfection and sterilization of patient-care items or equipment.² This classification scheme is so clear and logical that it has been retained and refined.³ Spaulding believed that the nature of disinfection could be understood more readily if instruments and items for patient care were divided into 3 categories based on the degree of risk of infection involved in the use of the items. The 3 categories he described were critical (enters sterile tissue and must be sterile), semicritical (contacts mucous membranes or non-intact skin and requires high-level disinfection), and noncritical (comes in contact with intact skin and requires low-level disinfection). The Spaulding classification remains the basis for current guidelines on sterilization and disinfection of medical devices.⁴ For example, endocavity ultrasound probes should undergo cleaning and then high-level disinfection between patients.⁴

Use of UV-C Disinfection in Healthcare Facilities

The electromagnetic spectrum is divided into bands based on wavelength of the radiation. From low to high frequency these are: radio waves, microwaves, infrared, visible light, ultraviolet (UV), X-rays, and gamma rays. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications.⁵ Ultraviolet light sits between the visible spectrum and the X-ray range. The UV wavelength spectrum ranges from 400nm to 100nm and is divided into 3 categories: UV-A (315nm to 400nm), UV-B (280nm to 315nm), and UV-C (100nm to 280nm).^6,7 UV-C light is absorbed by the earth’s atmosphere and does not reach the earth. UV-C irradiation can be used as a disinfection technique to kill or inactivate microorganisms.⁶ UV-C inactivates microbes by damaging their genetic material, thereby inhibiting their capacity to carry out vital functions.

UV can be generated from artificial sources including low-pressure mercury lamps and pulsed xenon lamps. Some mobile devices use low-pressure mercury lamps to produce continuous UV-C with a peak wavelength of 254 nm, while others use pulsed-xenon lamps that produce light with a much broader spectrum (200–320 nm).⁷ The effectiveness of germicidal UV irradiation depends on the UV dose (how much UV light reaches the microbe; measured as radiant exposure), susceptibility the microbe is to the given wavelength(s) of UV light, defined by the germicidal effectiveness curve (254nm is highly microbiocidal), and duration of exposure.  

A variety of factors impact the germicidal effectiveness of UV-C irradiation including the following: Wavelength of irradiation, distance of the UV-C to surface/device being disinfected (intensive of UV irradiance is inversely proportional to the square of distance), energy produced by the UV-C emitter (i.e., uW/cm2), duration of exposure, line of sight to surface/device being disinfected, and orientation of the emitter.⁷ In addition, intrinsic susceptibility of the pathogen to UV-C irradiation also impact effectiveness (e.g., spores are more resistant than vegetative bacteria).  

Ultraviolet germicidal irradiation (UVGI) is commonly used in healthcare in several applications for disinfection. First, UVGI units have been used for air disinfection since the 1930s.⁶ The Centers for Disease Control and Prevention (CDC) noted that upper-room germicidal UV (GUV) is best used as part of a layered approach to reducing exposures to airborne pathogens, along with other strategies such as ventilation systems, and that is best used in group settings.⁸ The use of GUV in healthcare facilities has been reviewed.^9,10 Second, devices that deliver UV-C irradiation have been used as an adjunct for hospital room disinfection. A narrative review of randomized clinical trials¹¹ and meta-analysis¹² have demonstrated that UV-C devices used as an adjunct to terminal disinfection can reduce the frequency of healthcare-associated infections. Third, a UV-C (254nm) chamber (Chronos®) is now a US Food and Drug Administration cleared device for high-level disinfection of endocavity ultrasound probes.¹³ This device is effective in killing or inactivating Staphylococcus aureus, Staphylococcus haemolyticus, Streptococcus agalactiae, Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, Candida albicans, and Trichomonas vaginalis.¹³ In addition, this device has been shown to inactive human papilloma virus.¹⁴ A recent scoping review of UV-C devices for high-level disinfection of semi-critical devices (i.e., devices that have contact with mucous membranes or non-intact skin) demonstrated that “The bacterial reduction obtained with UV-C light disinfection was not inferior compared to other disinfection methods that are currently being used.”¹⁵

Advantages of UV-C Disinfection for Semi-Critical Devises Compared with Chemical-Based Approaches

Advantages of UV-C disinfection compared to chemical-based approaches include the following: More rapid disinfection, eliminates possible exposure of patients and healthcare-personnel to harmful chemicals, and eliminates disposal of chemicals into the waste stream. In addition, there is no evidence that use of UV-C will lead to development of further resistance in multidrug-resistant bactria.¹⁶

UV-C Disinfection Activity Against Emerging and Multidrug-Resistant Pathogens

UV-C is capable of inactivating a wide range of pathogens including Gram-positive and Gram-negative bacteria,¹³ human papilloma virus,¹⁴  multidrug-resistant bacteria,¹⁶ and Candida auris.¹⁷

Future of UV-C Disinfection in Healthcare

Use of UV-C devices in healthcare facilities is likely to increase in the future. Use of a UV-C device for terminal room disinfection in selected rooms has recently been demonstrated to reduce hospital-wide acquisition and infection with multidrug-resistant organisms and Clostridioides difficile.¹⁸ Hand-held UV-C devices are being evaluated for surface disinfection.¹⁹ Wall mounted far UV-C devices are being investigated for continuous room disinfection.²⁰

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References

1. Rutala WA, Boyce JM, Weber DJ. Disinfection, sterilization and antisepsis: An overview. Am J Infect Control. 2023 Nov;51(11S):A3-A12.

2. EH. Spaulding. Chemical disinfection of medical and surgical materials. C Lawrence, SS Block (Eds.), Disinfection, Sterilization, and Preservation, Lea & Febiger (1968), pp. 517-531.

3. Rowan NJ, Kremer T, McDonnell G. A review of Spaulding's classification system for effective cleaning, disinfection and sterilization of reusable medical devices: Viewed through a modern-day lens that will inform and enable future sustainability. Sci Total Environ. 2023 Jun 20;878:162976.

4. Shenoy ES, Weber DJ, McMullen K, Rubin Z, Sampathkumar P, Schaffzin JK, Sickbert-Bennett E, Washer L, Yokoe DS, Calderwood AH, Chinn R, Day M, Garcia-Houchins S, Javaid W, Klacik S, Kyle E, Murthy RK, Wood A, Rutala WA. Multisociety guidance for sterilization and high-level disinfection. Infect Control Hosp Epidemiol. 2025 Apr 28:1-23.

5. Wikipedia. Electromagnetic spectrum. See: https://en.wikipedia.org/wiki/Electromagnetic_spectrum#Ultraviolet_radiation. Accessed 10 January 2026.  

6. Wikipedia. Ultraviolet germicidal irradiation. See: https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation. Accessed 10 January 20126.  

7. Boyce JM, Donskey CJ. Understanding ultraviolet light surface decontamination in hospital rooms: A primer. Infect Control Hosp Epidemiol. 2019 Sep;40(9):1030-1035.

8. Centers for Disease Control and Prevention. About germicidal ultraviolet (GUV). See: https://www.cdc.gov/niosh/ventilation/germicidal-ultraviolet/index.html. Accessed 10 January 2026.  

9. Memarzadeh F, Olmsted RN, Bartley JM. Applications of ultraviolet germicidal irradiation disinfection in health care facilities: effective adjunct, but not stand-alone technology. Am J Infect Control. 2010 Jun;38(5 Suppl 1):S13-24.

10. Memarzadeh F. A Review of Recent Evidence for Utilizing Ultraviolet Irradiation Technology to Disinfect Both Indoor Air and Surfaces. Appl Biosaf. 2021 Mar 1;26(1):52-56.

11. Weber DJ, Rutala WA, Anderson DJ, Sickbert-Bennett EE. “No touch” methods for health care room disinfection: Focus on clinical trials. Am J Infect Control. 2023 Nov;51(11S):A134-A143.

12. Marra AR, Schweizer ML, Edmond MB. No-Touch Disinfection Methods to Decrease Multidrug-Resistant Organism Infections: A Systematic Review and Meta-analysis. Infect Control Hosp Epidemiol. 2018 Jan;39(1):20-31.

13. Siewierski T, Fibiger G, Różańska A, Pietrzyk A, Jachowicz-Matczak E, Romaniszyn D, Wójkowska-Mach J. UV-C Light-Based Decontamination of Transvaginal Ultrasound Transducer: An Effective and Fast Way for Patient Safety in Gynecology. J Clin Med. 2025 Dec 2;14(23):8561.

14. Pichon M, Lebail-Carval K, Billaud G, Lina B, Gaucherand P, Mekki Y. Decontamination of Intravaginal Probes Infected by Human Papillomavirus (HPV) Using UV-C Decontamination System. J Clin Med. 2019 Oct 24;8(11):1776

15. Halmans Y, Wellenstein D, Hopman J, Takes R, van den Broek G. Is UV-C light disinfection suitable as a disinfection method for medical devices: a scoping review. Antimicrob Resist Infect Control. 2025 Nov 29;15(1):2.

16. Choi H, Chatterjee P, Hwang M, Stock EM, Lukey JS, Zeber JE, Jinadatha C. Can multidrug-resistant organisms become resistant to ultraviolet (UV) light following serial exposures? Characterization of post-UV genomic changes using whole-genome sequencing. Infect Control Hosp Epidemiol. 2022 Jan;43(1):72-78.

17. Rutala WA, Bolomey AC, Cadnum JL, Donskey CJ. Inactivation and/or physical removal of Candida auris from floors by detergent cleaner, disinfectants, microfiber, and ultraviolet C light (UV-C). Infect Control Hosp Epidemiol. 2024 Mar;45(3):390-392.

18. Anderson DJ, Moehring RW, Weber DJ, Lewis SS, Chen LF, Schwab JC, Becherer P, Blocker M, Triplett PF, Knelson LP, Lokhnygina Y, Rutala WA, Sexton DJ; CDC Prevention Epicenters Program. Effectiveness of targeted enhanced terminal room disinfection on hospital-wide acquisition and infection with multidrug-resistant organisms and Clostridium difficile: a secondary analysis of a multicentre cluster randomised controlled trial with crossover design (BETR Disinfection). Lancet Infect Dis. 2018 Aug;18(8):845-853.

19. Byrns G, Barham B, Yang L, Webster K, Rutherford G, Steiner G, Petras D, Scannell M. The uses and limitations of a hand-held germicidal ultraviolet wand for surface disinfection. J Occup Environ Hyg. 2017 Oct;14(10):749-757.

20. Kaple CE, Memic S, Cadnum JL, Donskey CJ. Evaluation of an automated far ultraviolet-C light technology for decontamination of surfaces and aerosolized viruses in bathrooms. Antimicrob Resist Infect Control. 2024 Sep 29;13(1):114.

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