The importance of disinfection in healthcare settings

Healthcare facilities are vital to managing infectious diseases, but they also play a part in spreading healthcare-associated infections (HAI) to other patients through cross-infection. 

Infection prevention and control (IPC) is critical to protect patients and maintain safety of staff at hospitals and private clinics. Over the centuries, the search for improved methods of disinfection to prevent the spread of disease has led to new technologies that could reduce the risk of HAIs.

Early Methods of Disinfection 

Before scientists in the 1800s succeeded in demonstrating that microorganisms existed and could cause diseases in people and animals, these pathogens often were disinfected successfully with several methods, including physical, chemical, and even biological. These methods were originally based on empirical observations.(1)

At least as far back as Aristotle, physical disinfection was probably most easily accomplished with the use of heat. Boiling or distilling drinking water to prevent disease became common. The burning or burial of diseased carcasses and dead humans controlled the spread of plagues. 

Simple chemical products, such as derivatives of sulfur were used to disinfect homes and objects contaminated by plagues. Compounds of mercury, such as mercurochrome, were used to treat certain diseases, and copper was used to prevent the growth of fungi and rot on wood.

The chemical/industrial revolution

Along with the Industrial Revolution (1760-1840) and the invention of the coal-fired steam engine, the rise of the coal and wood tar chemical industry led to all sorts of experiments to find new chemical disinfectants, such as carbolic acid.(2) 

After Louis Pasteur (1822-1895) disproved the theory of spontaneous generation of microorganisms, surgeon Joseph Lister learned that germs from the air could cause infections. In the 1860s, Lister began to use a steam spray of carbolic acid in his operating theater to kill microorganisms that could infect the open wounds of patients. He later began to apply the acid directly to the skin. Lister also advocated for antiseptic surgeries, advising doctors to wear clean gloves and wash their hands before operations.(3) 

The Rise of Chemical Disinfectants 

In the 19^th Century, many new chemical formulations were developed to sterilize microorganisms in healthcare settings. These included hydrogen peroxide, chlorine bleach, hypochlorite, iodine solutions, as well as patented formulas. Experimentation continued into the 20^th century, with the development of methylene blue, the quaternary ammonium compounds (quats), chlorhexidine, peracetic acid, and glutaraldehyde.(4) 

Each chemical disinfectant was exhaustively tested at different exposure times working on different pathogens and different surfaces. For example, various versions of the quats were found to be useful for disinfecting equipment used with patients such as blood pressure cuffs, while others such as alcohol had negative effects on the equipment.(5)

Drawbacks to chemical methods

Some of the newly developed disinfectants eventually proved to cause environmental problems as well as serious side effects in patients and hospital staff. For example, ethylene oxide (EtO) was determined to cause cancer and acute and chronic health problems, while glutaraldehyde causes asthma, nosebleeds, headaches, and throat and eye irritation. Also, the use of certain chemicals for disinfection, such as glutaraldehyde, caused some pathogens to become resistant over time. 

This led to developments of more alternative technologies for disinfecting hospital equipment, including the use of ortho-phthalaldehyde (OPA) as a glutaraldehyde alternative in sterilizing endoscopes. The OPA technology costs more, creates some environmental issues, and still causes certain side effects in patients.(6) 

Automated reprocessing machines using peracetic acid were also developed for disinfection of hospital equipment, such as flexible channel-less ENT scopes. As with other types of chemical disinfectants, these systems have certain drawbacks, such as high costs, the need for a large inventory of scopes, water, long drying time and corrosion of equipment.

Advancements in Physical Disinfection Methods 

Alongside advances in chemical disinfection in the 19^th Century, several innovations were made in physical disinfection methods. In the 1860s, Pasteur published his germ theory and proved that heat could kill microorganisms. 

Soon after, an associate of Pasteur’s, Charles Chamberland, developed a pressure steam sterilizer, known as the Chamberland autoclave, used for sterilizing surgical dressings and equipment with steam.(7)

Ionizing radiation and X-rays were discovered in 1879 and 1895, respectively. These were found to destroy microorganisms, which led to the idea of using radiation and particle acceleration as a means of sterilization.(8) 

The late 1800s was also the period when scientists discovered that sunlight could disinfect certain pathogens. More recently, the medical disinfection field has been enhanced by the technological advances of integrating automated disinfection methods into healthcare, including devices that make use of UV light. 

This was the beginning of research and inventions leading to today’s advanced UV light technology for disinfection in hospital settings.

UV Light as a Disinfectant 

Non-ionizing radiation in the form of ultraviolet light has a strong germicidal effect. The UV spectrum can’t be seen by the naked eye and ranges in wavelength from 400 nanometers to about 100 nanometers, and can further be divided into: 

• UV-A (400–315 nm)
• UV-B (315–280 nm)
• UV-C (280–100 nm) 

The best wavelengths for inactivating pathogens occur between 240 nm and 280 nm, in the UV-C range, with the maximum microbicidal activity occurring about 254 nm. 

UV-C light causes chemical bonds to fuse in the DNA and RNA of bacteria and viruses, preventing them from multiplying and causing them to die. This type of disinfection is chemically non-toxic, environmentally friendly, and does not damage most types of equipment. It should be noted that direct exposure to UV light can harm human eyes and skin.

Innovation and Evolution of UV-C Light Technology 

Soon after scientists discovered that sunlight could disinfect certain pathogens, the gas discharge lamp was invented which produces light in the UV range (1901). 

In 1903, Nils Ryberg Finsen, a Danish physician, was awarded the Nobel Prize in Physiology or Medicine for treating bacterial infections in patients by UV light. Then in 1929, the mechanism of genetic damage by UV-C in microorganisms was described in a scientific paper. 

Over the 20^th Century, UV-C light began to be used commercially to disinfect drinking water and wastewater, as well as the air in some hospital rooms. In spite of its obvious effectiveness, safety and practicality for disinfection, it wasn’t until the 21st century that this powerful method was fully developed for disinfecting medical equipment in healthcare settings, with UV-Smart leading the way.(9) 

UV-C Light in Modern Healthcare 

In modern healthcare settings, a new technology based on UV-C light, called Impelux^TM, guarantees an effective way to combat HAIs. This technology, developed by UV Smart, has been incorporated into three products for safely and easily disinfecting medical equipment, the D25+, the D45 and the D60.

D25+

Without the need for chemicals or water, the UV Smart D25+ can disinfect small (non)invasive medical instruments like wireless probes, rigid endoscopes and handheld items, such as stethoscopes and smartphones. The user follows the simple and easy steps on the visual display. When the disinfection cycle of 25 seconds is complete, the user is notified. The UV-C light source in the box only turns on when the device is fully closed, making it safe to use. The D25+ was tested and met or exceeded the results required by the European standards for disinfecting surfaces and instruments.(9) 

D45

In just seconds, the UV Smart D45 disinfects the surface of ultrasound probes, helping mitigate the spread of infections such as STDs and HIV. The sustainable cold and dry process makes use of UV-C light and requires no water, wipes, chemicals, or consumables during disinfection. The convenient D45 unit integrates easily into healthcare settings and can be located right in the patient room. The disinfection efficiency of the UV Smart D45 has been validated and proven by extensive research conducted in clinical laboratories and medical centers.(10)

D60

The UV Smart D60 quickly and easily disinfects flexible channel-less ENT endoscopes and TEE probes in just 60 seconds – so they can be reused much faster. No detergents or liquids are needed for the disinfection cycle by the D60. The lack of corrosive chemicals, wastewater, or high temperatures, along with the fast reprocessing time means that the D60 can make this essential disinfection activity convenient, easy, effective, and safe. In a recent study at the University of Marburg, the UV Smart D60 showed good disinfection results in a routine clinical setting. The study concluded that the D60 “...has the potential for fast and simple point-of-care disinfection, and offers substantial advantages to standard disinfection methods for flexible endoscopes without a working channel.”(11) 

UV-C Light: The future of healthcare disinfection

As more sustainable solutions become critical in today’s environment and more resistant bacteria such as MRSA appear, innovative new technologies such as UV-C light disinfection will be required to maintain healthcare safety. Until now, none of the other methods, from simple heat, steam, or soap & water to the most sophisticated chemical or physical disinfection systems, has proven to be ideal.

UV-C light disinfection kills microorganisms in seconds by disrupting their reproductive machinery. It requires no dangerous chemicals or consumables.

Harnessed by UV-Smart’s Impelux technology, UV-C light has proven to be fast, convenient, safe, and effective in preventing HAIs. It is the future of disinfection in healthcare settings. To find out more, click here.

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References and Further Reading

1. History of disinfection from early times until the end of the 18th century https://doc.woah.org/dyn/portal/digidoc.xhtml?statelessToken=Vbv8VkKyMJ-XBsNMhc69OiRUIXF6sbtkplrBoYg0QgU=&actionMethod=dyn%2Fportal%2Fdigidoc.xhtml%3AdownloadAttachment.openStateless 

2. A brief history of heat and chemical preservation and disinfection https://ami-journals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2672.1991.tb04657.x 

3. Joseph Lister (1827-1912): A Pioneer of Antiseptic Surgery .https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9854334/ 

4. A brief history of heat and chemical preservation and disinfection https://ami-journals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2672.1991.tb04657.x 

5. Chemical Disinfectants  https://www.cdc.gov/infectioncontrol/guidelines/disinfection/disinfection-methods/chemical.html 

6. Reducing Ethylene Oxide and Glutaraldehyde Use  https://19january2017snapshot.epa.gov/www3/region9/waste/archive/p2/projects/hospital/glutareth.pdf

7.Charles Chamberland, the Inventor of Sterilization Tools https://www.pasteur.fr/fr/institut-pasteur/notre-histoire/charles-chamberland-inventeur-outils-sterilisation

8. Other Sterilization Methods .https://www.cdc.gov/infectioncontrol/guidelines/disinfection/sterilization/other-methods.html

9. UV-C Disinfection: Safety, efficiency and practical application .https://assets-global.website-files.com/62f496764efd72be7e7c0df0/62f496764efd729a6c7c0ffd_Safety%2C%20efficiency%20and%20practical%20application.pdf 

10. https://www.uvsmart.nl/d45

11. UV light‑based reprocessing of flexible endoscopes without working channel in Oto‑Rhino‑Laryngology: an effective method?. https://assets-global.website-files.com/62f496764efd72be7e7c0df0/62f496764efd72b5977c0ff4_UV%20light%E2%80%91based%20reprocessing%20of%20fexible%20endoscopes.pdf