Robert A. Garcia, BS, MT(ASCP), CIC, FAPIC
Article excerpt reprinted courtesy of CASPR Medik™

The development of healthcare-associated infections (HAIs) remains a major national patient safety issue, with upward of 1.7 million infections and 99,000 deaths occurring annually. The overall direct cost of HAIs to hospitals has been reported to be in the range from $28 billion to $45 billion1.

Recent analysis of data from the Agency for Healthcare Research and Quality (AHRQ) indicates that facilities incur increased costs ranging from 47% to 70% for medical harms, such as catheter-related bloodstream infections (CRBSIs) and catheter-associated urinary tract infections (CAUTI) when patient re-admissions are considered2.

Pathogen transmission

The routes of transmission of nosocomial pathogens in healthcare settings have been well researched3. Patients colonized or infected with pathogens may:

  • shed organisms onto their skin, bedding or clothing, such as gowns
  • contaminate nearby environmental surfaces
  • contaminate portable equipment used in their care

The available evidence suggests that pathogen transfer occurs frequently. Wolfensberger and colleagues’ recent review of the published literature indicates transfer frequencies of pathogens from patients and their environment to healthcare provider (HCP) hands, gloves and gowns are 33%, 30% and 10%, respectively. HCP behaviors that only entailed contact with an environmental source led to transfer frequencies > 40% for such pathogens as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile4.

One recent study underscores the potential for patient shedding of pathogens onto their hospital gowns which, in turn, may act as sources for further transmission onto fomites. Researchers examined the burden of MRSA on multiple areas of clothing worn by patient carriers, including at the neck, chest, waistline, sleeve cuffs and pockets. MRSA was recovered from 74% of sampled gown sites.

Further assessment was made as to the potential for transfer of the organism from the clothing of MRSA carriers to HCP gloves. MRSA transfer occurred 62% of the time when fingertips of sterile gloves were contacted with contaminated areas of clothing of identified carriers. When MRSA carriers were placed in wheelchairs, 50% of 10 carriers transferred MRSA to a wheelchair surface within 20 minutes5.

An estimated 20% to 40% of HAIs are attributed to cross-infection from organisms on the hands of healthcare personnel6. Contamination of the hands of HCPs results from direct contact with a colonized or infected patient or from contaminated fomites – hands thus serving as the vector to additional surfaces or to a new susceptible patient. The hands of HCPs are just as likely to be contaminated by touching an environmental source as would be by direct contact with a patient7. The risk of further pathogen transfer increases knowing that observations have noted that HCPs wash their hands to lesser degrees after contact with a patient’s environment than when directly contacting the patient8.

Advanced technologies

Hospitals are increasingly investigating alternative solutions to supplement traditional practices in disinfection of the patient environment due to failures associated with achieving thorough patient room cleaning, whether due to inadequate or overlooked cleaning of objects, lack of proper supervision and monitoring, lack of resources, low levels of hand hygiene or other factors. Among these new technologies are antimicrobial coatings of surfaces and use of ultraviolet light (UV) or hydrogen peroxide vapors or aerosolization.

UV-C/HP background

Among the best studied of new “no touch” room disinfection technologies are mobile robots that incorporate the automated emission of chemical vapors, aerosols or UV. Chemical vapor and aerosolizing technology use hydrogen peroxide as the primary disinfecting agent. The majority of UV or hydrogen peroxide (HP) systems provide the technology using a portable machine that is set up in the patient’s room as per the individual manufacturer’s instructions.


UV irradiation eradicates organisms by breaking the molecular bonds in DNA. Systems using UV-C produce wavelengths between 200 to 270 nm, a zone which lies in the known germicidal range of the electromagnetic spectrum (200 to 320 nm). A second UV device that uses pulse xenon technology (UV-X) also is widely available. Such factors as organic load, pathogen type, intensity, surface types, distance of the surface from the device, placement of the machine in the room, exposure time, room size and configuration, and air movements contribute to the efficacy of UV46.

Weber and colleagues provide insight on nine studies assessing the efficacy of UV irradiation in reducing microbial loads on intentionally contaminated environmental surfaces34. Several important points can be deduced from these results:

  • Use of UV for 15 to 20 minutes achieved a > 3-log10 reduction in vegetative bacteria, including MRSA, VRE and Acinetobacter baumanii.
  • C. difficile spores also are decreased by > 3-log10 as seen with other vegetative bacteria but require extended UV treatment times of 35 to 100 minutes.
  • Increasing the distance from the device reduced the killing efficacy for MRSA, VRE and C. difficile.
  • The effectiveness of UV was reduced when the surface was not in the direct line of sight of the UV emission.
  • Spreading the inoculum over a wider area increased the ability to kill the organisms47-51.

Manufacturers recommend that facilities using UV may need supplemental room treatments after the initial decontamination cycle. This would entail repositioning the mobile unit with consideration of surfaces that may not have had direct line-of-site exposure during the first decontamination cycle, including adjoining or opposite surfaces of bed rails, furnishings and equipment52, rolling or stationary computers, along with accessories like keyboards and mice53, as well as the surfaces of adjoining bathrooms54,55. The importance of providing optimal line-of-site positioning during UV decontamination becomes clearer when light intensity is considered. A simulation trial in which the researchers coated the walls of test rooms with reflective paint resulted in enhanced intensity of ultraviolet light on indirect surfaces in the trial rooms and, in turn, was associated with significant log-10 reductions of both MRSA and C. difficile test organisms56. Several trials have examined the effectiveness of UV-C devices on decontaminating patient rooms after patient discharge.

In nine published studies using either UV-C or ultraviolet pulsed xenon devices (UV-PX), pathogens such as MRSA, VRE and Acinetobacter spp. were reduced in 1,025 minutes, with three studies using two to three cycles. C. difficile cycle times ranged from 10 to 45 minutes. The frequency of positive surface sites post-treatment was <11%, while log-10 reductions were all reported as two or less42.

The first randomized clinical trial to assess a UV-C no-touch technology is the Benefits of Enhanced Terminal Room Disinfection (BETR-D) study, the results of which were published in 201757. This crossover trial conducted at nine hospitals examined three strategies for enhanced room decontamination: use of a quaternary ammonium compound plus UV-C, bleach only or bleach plus UV-C. Treated rooms were those that housed a patient identified with MRSA, VRE or C. difficile. Outcomes measured included subsequently admitted patients acquiring an HAI with one of the target pathogens. Both hand hygiene and terminal room cleaning measurement compliance showed no differences at baseline or among the three study groups.

The study concluded that the addition of a UV-C device to the standard disinfection strategy during terminal decontamination decreased the acquisition of a target organism by approximately 10% to 30%, suggesting that the environment is responsible for a significant portion of MDRO acquisition23.

No significant differences were found in the incident rates of target organisms when using bleach or bleach plus UV-C when compared to use of a quaternary ammonium compound alone. Insights provided by the authors of the BETR-D study on implementation challenges encountered with UV-C devices indicated the need to overcome two key barriers: establishing priorities for room selection and overcoming time constraints to allow environmental staff sufficient time to employ the enhanced terminal disinfection method prior to admission of the next patient58. In this study, the assigned hospital staff required an additional 10 to 20 minutes for each enhanced terminal disinfection strategy for rooms in which patients were to be admitted from an emergency room. Furthermore, use of the UV-C device was limited to only 60% of “seed” rooms59.

Continuous full facility decontamination

hospital-janitorUnderstanding the evolution and the principle designs of environmental disinfecting technology and, most importantly, the limitations inherent in the methods of operation, has led science to the next level in decontamination concept. Research engineers have designed a continuous disinfection technology using a natural catalytic converter inserted into the ducts of an HVAC system. This new device converts H2O and O2 in the air into hydrogen peroxide (H2O2). The device uses a multi-wavelength ultraviolet light to illuminate target surfaces consisting of a honeycomb matrix treated with photocatalytic coating consisting of titanium oxide (TiO2) and other reactive metals added to enhance the overall catalytic effect.

When inserted into the ducts of the HVAC system, the device reacts with water molecules in humidity to continuously create predominantly H2O2 molecules, which exit the duct and disperse throughout the targeted area, safely covering the surfaces of occupied rooms and patient care areas with effective oxidizing molecules that work to reduce the bioburden of clinically relevant pathogens.

Studies currently being conducted using continuous natural catalytic converter decontamination in hospital patient rooms have indicated an average reduction in environmental microburden of between eight and 10-fold as compared to pre-activation baseline samples documented through environmental sampling of high-touch points. Independent clinical studies of the effectiveness of the continuous disinfection technologies have shown at least a >3-log-10 reduction in clinically relevant pathogens associated with environmental contamination (unpublished data).

One added benefit of the technology demonstrated in the hospital trials is the impact on HCP absenteeism. In one trial in a large 527-bed hospital, the technology was employed to treat the entire area of the ICU, including patient rooms, nurse stations and work areas. Absenteeism rates were reduced to 752 hours during a four-month period from 1,316 hours for the same period during the previous year. The decrease represented a 42% reduction and represented a gain of over 80% of an FTE.


Environmental contamination of hospital patient rooms poses a significant risk for the subsequent transfer of pathogens and development of hospital-acquired infections. “No-touch” room decontamination technologies have evolved to address this issue using methodologies that have been well studied.

However, mobile technologies have limitations that have been reported in the scientific literature. A newly designed device that delivers continuous decontamination effect using a natural catalytic conversion technology built into HVAC systems has demonstrated preliminary positive results in reducing environmental contamination with pathogens.

The technology is the first disinfection solution that is practical to employ throughout an entire facility to address not just highly contaminated patient rooms but all patient rooms, nurse stations, public areas, floors and work areas.

CASPR Medik™ has all of the benefits of a robot with the enhanced ability to cover the entire environment of care, continuously. The natural catalytic converter solution is quickly and easily installed throughout the ductwork of existing HVAC system, where it provides continuous facility-wide surface protection. CASPR works on its own, without an operator or any human interaction, providing effortless supplemental protection for all surfaces throughout the environment of care. The disinfection technology is proven effective against relevant pathogens and has been linked to reduced HAIs. To view the full article, including references, visit


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