UV Technology for UV Technology for Disinfecting SurfacesDisinfecting Surfaces

By Dr Anjum HashmiMBBS,CCS(USA),MPHInfection Control Director,Maternity & Children’s HospitalNajran KSA

IntroductionIntroduction• Healthcare-associated infections remain an

important source of morbidity and mortality, with an estimated 1.7 million infections and 0.1 million deaths annually.

• The major source of nosocomial pathogens is thought to be patients’ endogenous flora, but an estimated 20%–40% of healthcare-associated infections have been attributed to cross infection via the hands of healthcare personnel.

• Contamination of the hands of healthcare personnel could in turn result directly from patient contact or indirectly from touching contaminated environmental surfaces.

IntroductionIntroduction• The risks associated with hospital & community

acquired infections are enormous for both human health and medical costs.

• Scientific literature confirms that Clostridium difficile, MRSA, VRE, Acinetobacter baumannii, and influenza are transmitted via environmental surfaces.

IntroductionIntroduction• Published studies indicate that only 50% of

environmental surfaces in a typical OR suite or patient room may be effectively disinfected by routine environmental cleaning.

• Thus patient’s risk of contracting an HAI increases 100% when the previous room occupant had been diagnosed with an infection.

““Targeting Zero” initiative Targeting Zero” initiative • Recently, APIC began a “Targeting Zero” initiative

focused on eliminating HAIs. • Improvements have been made in infection control

in recent years but, the environment remains a significant problem.

• We are still cleaning the environment in the same manner as we were doing decades ago, except change to new chemicals.

• We will not achieve zero HAIs until new technologies are used in the environmental cleaning sector as well.

No-Touch Disinfection System No-Touch Disinfection System

• No-touch disinfection, also called “area disinfection," is a means of disinfecting an enclosed space.

• This can be achieved using either ultraviolet light (UV) or hydrogen peroxide vapor (HPV).

• In both cases, a device is placed into a patient room, operating room or other area while the room is unoccupied and the device is run for specified time (disinfection cycle).

Mechanism of ActionMechanism of Action• UV-C technology rapidly and cost effectively deactivate

viruses, mold and bacteria that could otherwise threaten people's health.

• UV-C energy passes through the cell walls of bacteria, viruses and bacterial spores & it is absorbed by the DNA, RNA and proteins.

• The primary mechanisms of damage created by UV-C is the fusing of the strands of DNA creating what is known as "thymine dimers."

• Once the DNA is fused, the organism can no longer replicate and is, therefore, no longer infectious. The technical term for this is "deactivation."

Type of Ultraviolet LightType of Ultraviolet Light• The application of UV-C energy to deactivate

microorganisms is known as Germicidal Irradiation or UVGI.

• Optimal wavelengths vary for UV-C disinfection of different organisms. On average, wavelengths of 250-265 nm are where peak DNA absorption occurs.

• Mercury Ultraviolet It is most familiar form of UV is that is produced by mercury vapor lamps. In these lamps, the mercury vapor is ionized to create UV-C of 254 nm.

• Pulsed Xenon Ultraviolet (PX-UV) It is produced by pulsing a xenon lamp which produces a broad spectrum UV (from 200 nm to 320 nm) covering entire germicidal UV band.

Literature ReviewLiterature Review• UV-C light unit significantly reduced aerobic

colony counts and C. difficile spores on contaminated surfaces in patient rooms.

• UV -C technology eliminate more than 3-log10 vegetative bacteria (MRSA, VRE, and Acinetobacter baumannii) and more than 2.4-log10 C. difficile seeded onto Formica surfaces in experimentally contaminated patient rooms.

• William A. Rutala, David J. Weber, Are Room Decontamination Units Needed to Prevent Transmission of Environmental Pathogens? Infection Control and Hospital Epidemiology August 2011, vol. 32, no. 8

Literature ReviewLiterature Review• There is ample evidence that no-touch systems

such as UV-C light can reduce environmental contamination with healthcare-associated pathogens.

• UV-C light unit significantly reduced aerobic colony counts and C. difficile spores on contaminated surfaces in patient rooms.

• John M. Boyce, Nancy L. Havill, Brent A. Moore, Terminal Decontamination of Patient Rooms Using an Automated Mobile UV Light Unit. Infect Control Hosp Epidemiol 2011;32(8):737-742

Mean number of colony-forming units (CFU) of C. difficile, MRSA, and VRE from contaminated surfaces in hospital rooms before & after disinfection with UV .

Two-hundred sixty-one total surfaces from 66 rooms were cultured, including call lights, bedside tables, telephones, and bed rails.

Nerandzic et al. Evaluation of an automated ultraviolet radiation device for decontamination of Clostridium difficile and other healthcare-associated pathogens in hospital rooms. BMC Infectious Diseases 2010, 10:197

Mean aerobic colony counts before and after UV light Mean aerobic colony counts before and after UV light treatment for 5 high-touch surfaces in 20 roomstreatment for 5 high-touch surfaces in 20 rooms

Literature ReviewLiterature Review• Germicidal Irradiation or UVGI is very

effective in decontamination of Acinetobacter baumannii form all metal surfaces i.e., complete killing of Acinetobacter baumannii from contaminated surfaces was achieved with Ultraviolet C Light.

• Vipin K. Rastogi, Vipin K. Rastogi, Lalena Wallace, Lisa S. Smith. Disinfection of Acinetobacter baumannii-Contaminated Surfaces Relevant to Medical Treatment Facilities with Ultraviolet C Light. MILITARY MEDICINE, 172, 11:1166, 2007

Literature ReviewLiterature Review• Pulse xenon ultraviolet light is an effective

and efficient means of disinfecting surfaces contaminated with Clostridium difficile spores, MRSA and/or VRE, providing an alternative means to bleach and other chemical disinfectants for use in clinical settings.

• Mark Stibich. Use of Pulse Xenon Ultraviolet to Deactivate Clostridium Difficile spores, Methicillin-Resistant Staphylococcus Aureus and Vancomycin-Resistant Enterococci . SHEA/Fifth Decennial 2010.

UV irradiation AdvantagesUV irradiation Advantages• Reliable biocidal activity against a wide range of healthcare-

associated pathogens• Room surfaces and equipment decontaminated• Room decontamination is rapid (!15 minutes) for vegetative

bacteria Effective against Clostridium difficile, although longer exposure is required (!50 minutes)

• HVAC system does not need to be disabled, and the room does not need to be sealed

• UV light is residual-free and does not give rise to health or safety concerns

• No consumable products so costs include only capital equipment and staff time

• Good distribution in the room of UV energy via an automated monitoring system

UV irradiation DisadvantagesUV irradiation Disadvantages• All patients and staff must be removed from the room

before decontamination• Decontamination can be accomplished only at terminal

disinfection (i.e., cannot be used for daily disinfection) because the room must be emptied of people.

• Capital equipment costs are substantial.• Does not remove dust and stains, which are important

to patients and visitors; hence, cleaning must precede UV decontamination.

• Sensitive to use parameters (e.g., wavelength, UV dose delivered).

• Requires that equipment and furniture be moved away from walls.

UV Technology UV Technology Gadgets Gadgets

V-PADV-PAD

V-PAD (Portable Area V-PAD (Portable Area Disinfection)Disinfection)

• Four maximum output extended length UV-C lamps with combined output of 600 watts.

• Digital timer/counter to set disinfection cycle times of up to 99 hours.

• Four infrared motion sensors to automatically shut off device if someone enters the room during the disinfection cycle.

• Metal reflectors to protect lamp and better distribute UV energy

• Tri-color LED indicates status of operation.

TRU-D Smart UVC™ withTRU-D Smart UVC™ withSensor360™ technologySensor360™ technology

• TRU-D Smart UVC™ is the portable UV disinfection system that precisely measures reflected UVC emissions with Sensor360™ to automatically deliver the pathogen-lethal UV dose required for each room, dynamically compensating for room size, shape and other dose altering variables such as the position of contents, windows, blinds and doors.

• TRU-D uses narrow band UVC light for a high efficiency targeting of the DNA-disrupting wavelength that stops pathogens.

• TRU-D is safe to use in rooms with glass windows and doors. UVC is not transmitted through glass windows.

XENEX(XENEX(Hospital Disinfection)) Hospital Disinfection)) • Pulsed-xenon UV lamp delivers the fastest,

most effective germicidal dose of any UV system

• Lamp™ system uses reflectors and movement to focus UV light toward “high-touch” surfaces

• On-board database logs system activity for utilization tracking and analysis

• Visible light filter blocks the bright xenon pulse, so that rooms with interior glass can be treated without Distraction

• Motion detection system and door guard ensure the safety of patients, visitors, and staff.

Reputed Hospitals Using UVGI Reputed Hospitals Using UVGI Presbyterian Hospital USAPresbyterian Hospital USAHenry Mayo Hospital USAHenry Mayo Hospital USA

Vancouver General Hospital Canada Vancouver General Hospital Canada

Cooley Dickinson Hospital, Northhampton, MA

Flux Ropes on the SunImage of magnetic loops on the sun, byNASA's Solar Dynamics Observatory (SDO).

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