Evaluation of an automated ultraviolet radiation device for decontamination of Clostridium difficile and other healthcare-associated pathogens in hospital rooms

<p>Abstract</p> <p>Background</p> <p>Environmental surfaces play an important role in transmission of healthcare-associated pathogens. There is a need for new disinfection methods that are effective against <it>Clostridium difficile </it>spores, but also safe, rapid, and automated.</p> <p>Methods</p> <p>The Tru-D™ Rapid Room Disinfection device is a mobile, fully-automated room decontamination technology that utilizes ultraviolet-C irradiation to kill pathogens. We examined the efficacy of environmental disinfection using the Tru-D device in the laboratory and in rooms of hospitalized patients. Cultures for <it>C. difficile</it>, methicillin-resistant <it>Staphylococcus aureus </it>(MRSA), and vancomycin-resistant <it>Enterococcus </it>(VRE) were collected from commonly touched surfaces before and after use of Tru-D.</p> <p>Results</p> <p>On inoculated surfaces, application of Tru-D at a reflected dose of 22,000 μWs/cm²for ~45 minutes consistently reduced recovery of <it>C. difficile </it>spores and MRSA by >2-3 log₁₀colony forming units (CFU)/cm²and of VRE by >3-4 log₁₀CFU/cm². Similar killing of MRSA and VRE was achieved in ~20 minutes at a reflected dose of 12,000 μWs/cm², but killing of <it>C. difficile </it>spores was reduced. Disinfection of hospital rooms with Tru-D reduced the frequency of positive MRSA and VRE cultures by 93% and of <it>C. difficile </it>cultures by 80%. After routine hospital cleaning of the rooms of MRSA carriers, 18% of sites under the edges of bedside tables (i.e., a frequently touched site not easily amenable to manual application of disinfectant) were contaminated with MRSA, versus 0% after Tru-D (<it>P </it>< 0.001). The system required <5 minutes to set up and did not require continuous monitoring.</p> <p>Conclusions</p> <p>The Tru-D Rapid Room Disinfection device is a novel, automated, and efficient environmental disinfection technology that significantly reduces <it>C. difficile</it>, VRE and MRSA contamination on commonly touched hospital surfaces.</p

Planes, Trains, and Automobiles: Use of Carbon Dioxide Monitoring to Assess Ventilation During Travel

Background: Travel poses a risk for transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other respiratory viruses. Poorly ventilated indoor settings pose a particularly high risk for transmission.   Methods:  We used carbon dioxide measurements to assess adequacy of ventilation during 5 trips that included air travel. During selected parts of each trip that involved indoor settings, we monitored carbon dioxide levels every 1 minute and recorded peak levels and the number of people present. Carbon dioxide readings above 800 parts per million (ppm) were considered an indicator of suboptimal ventilation.      Results: Carbon dioxide levels remained below 800 ppm during train rides to and from the airport and inside airports except in a crowded boarding area with ~300 people present. Carbon dioxide levels exceeded 800 ppm inside the airplanes, but the air was filtered with high efficiency particulate air filters. Carbon dioxide levels remained below 800 ppm in common areas of a hotel but exceeded 800 ppm in a hotel room with 2 to 3 occupants and in a fitness center with 3 people exercising. In restaurants, carbon dioxide levels increased above 800 ppm during crowded conditions with 24 or more people present and 75% or more seat occupancy. Conclusion: Our results suggest that ventilation may be sufficient to minimize the risk for airborne transmission in many situations during travel. However, ventilation may be suboptimal in some areas or under certain conditions such as in hotel rooms or when restaurants, fitness centers, or airplane boarding areas are crowded. There is a need for larger scale studies to assess the quality of ventilation in a wide range of community settings.  </jats:p

Evaluation of Far Ultraviolet-C Light for Decontamination of Organisms in Whole Milk and Chicken Manure

Background: The dissemination of highly pathogenic avian influenza (HPAI) A(H5N1) in US poultry and dairy cows poses a public health threat. Farm workers caring for infected animals are at risk to acquire infections due to exposure to contaminated milk or poultry feces and secretions. Far ultraviolet-C (UV-C) light could provide continuous decontamination of surfaces and air in agricultural settings, but efficacy against organisms in whole milk or chicken manure is unclear. Methods: We examined the efficacy of far UV-C light against bacteriophage MS2 and methicillin-resistant Staphylococcus aureus (MRSA) in phosphate-buffered saline (PBS), 5% fetal calf serum, whole milk, or 5%, 10%, and 25% chicken manure, both in liquid suspension and dried on surfaces. We also compared the efficacy of 300 mJ/cm2 doses of far UV-C and 254-nm UV-C light against the test organisms in liquid droplets or droplets dried on surfaces.  Results: For both test organisms, far UV-C achieved significantly smaller log10 reductions in whole milk and in chicken manure suspensions than in PBS or 5% fetal calf serum, both in liquid suspension and when dried on surfaces (P0.05) except 5% chicken manure (P<0.001).  Conclusions: Our results suggest that in the absence of prior cleaning and disinfection far UV-C and 254-nm UV-C light technologies may have limited efficacy as an adjunctive method to reduce the risk for transmission of HPAI from surfaces in high-risk settings on farms

What’s in a Handshake? Exploring the Best Form of Greeting to Prevent Hand to Hand Spread of Viruses

Background: Respiratory and enteric viruses are highly contagious pathogens that can be spread by contaminated hands and surfaces. We hypothesized that alternatives to handshake greetings that reduce the time and surface area of hand contact would be associated with decreased transfer of viral particles. Methods: In a simulation of hand-contact greetings, volunteers (N = 22) used a keyboard contaminated with the benign bacteriophage MS2 and then performed a handshake and fist bump with additional volunteers. To assess viral transfer, hands were cultured for MS2, and plaque-forming units (PFU) were compared for the different types of hand contact. Additional simulations (N = 10) were conducted to compare viral transfer with the fist bump versus a cruise tap greeting (ie, a modified fist bump involving single knuckle contact). Results: The handshake greeting resulted in significantly greater transfer of MS2 than the fist bump (1.31 vs 0.54 log10 PFUs, P &lt; .001) (Fig. 1A), but the frequency of transfer of virus was high for both greetings (91% transfer by handshake vs 59% by fist bump). The cruise-tap greeting did not result in reduced transfer of viral particles in comparison to the fist bump (Fig. 1B), and the frequency of transfer remained high (70%). Conclusions: The fist-bump and cruise-tap greetings could potentially reduce transmission of viruses in comparison to the handshake, but transfer occurred frequently, even with these greeting methods. To eliminate hand-to-hand transmission of respiratory and enteric viruses, alternative greeting methods that do not involve physical contact are needed.Funding: NoneDisclosures: None</jats:p

Efficacy of an upper room ultraviolet-C (UV-C) technology versus far UV-C light technologies in reducing aerosolized bacteriophage MS2

In a room with 6 air changes per hour, an upper room ultraviolet-C (UV-C) and 2 far UV-C technologies were similarly effective in reducing aerosolized bacteriophage MS2 in comparison to no intervention. Both UV-C technologies could be useful adjunctive measures to reduce the risk for respiratory virus transmission

Does the Fist Bump Transfer Less Methicillin-Resistant <i>Staphylococcus aureus</i> Than a Handshake?

Background: Contaminated hands are the most important source for transmission of pathogens in healthcare settings. It has been proposed that replacing the handshake with alternative greetings such as the fist bump might reduce the risk for pathogen transmission. Methods: In a cohort of 50 patients with methicillin-resistant Staphylococcus aureus (MRSA) colonization, we compared the frequency of transfer of MRSA by handshake versus fist bump versus cruise tap (ie, a modified fist bump involving knuckle-to-knuckle contact with a single finger). MRSA-colonized patients performed each greeting with research personnel wearing sterile gloves, and cultures were obtained to determine the number of colonies transferred. Transfer by handshake was also assessed after MRSA-colonized patients used alcohol-based hand sanitizer. Quantitative cultures were obtained to compare the burden of MRSA on the palm versus dorsum of the hands of the MRSA carriers. Results: As shown in Fig. 1, there was a significant reduction in the frequency of MRSA transfer for the cruise tap compared to the handshake, but not for the fist bump. Use of alcohol-based hand sanitizer by MRSA carriers also significantly reduced the risk for transfer of MRSA. There was no significant difference in the burden of MRSA on the dorsum versus the palm of the hands (mean +SE colonies recovered, 32.7+12.3 vs 27.3+12.7; P &gt; .05). Conclusions: The fist-bump greeting did not transfer less MRSA than a handshake. However, transfer was significantly reduced by a cruise-tap greeting or by handshake after the use of hand sanitizer. Modified greetings and patient hand hygiene are potential strategies to reduce transmission of healthcare-associated pathogens.Funding: NoneDisclosures: None</jats:p

Urinary Metabolites of Green Tea as Potential Markers of Colonization Resistance to Pathogenic Gut Bacteria in Mice

Background: The gut microbiome (GMB) generates numerous chemicals that are absorbed systemically and excreted in urine. Antibiotics can disrupt the GMB ecosystem and weaken its resistance to colonization by enteric pathogens such as Clostridium difficile. If the changes in GMB composition and metabolism are sufficiently large, they can be reflected in the urinary metabolome. Characterizing these changes could provide a potentially valuable biomarker of the status of the GMB. While preliminary studies suggest such a possibility, the high level of data variance presents a challenge to translational applications. Since many GMB-generated chemicals are derived from the biotransformation of plant-derived dietary polyphenols, administering an oral precursor challenge should amplify GMB-dependent changes in urinary metabolites.Methods: A course of antibiotics (clindamycin, piperacillin/tazobactam, or aztreonam) was administered SC daily (days 1 and 2) to mice receiving polyphenol-rich green tea in drinking water. Urine was collected at baseline as well as days 3, 7, and 11. Levels of pyrogallol and pyrocatechol, two phenolic molecules unequivocally GMB-dependent in man but that had not been similarly examined in mice, were quantified.Results: In confirmation of our hypothesis, differential changes in murine urinary pyrogallol levels identified the treatments (clindamycin, piperacillin/tazobactam) previously associated with a weakening of colonization resistance to Clostridium difficile. The changes in pyrocatechol levels did not withstand corrections for multiple comparisons.Conclusions: In the mouse, urinary pyrogallol and, in all likelihood, pyrocatechol levels, are GMB-dependent and, in combination with precursor challenge, deserve further consideration as potential metabolomic biomarkers for the health and dysbiotic vulnerability of the GMB.</jats:p