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

Abstract

Background: Environmental surfaces play an important role in transmission of healthcare-associated pathogens. There is a need for new disinfection methods that are effective against Clostridium difficile spores, but also safe, rapid, and automated.

Methods: 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 C. difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) were collected from commonly touched surfaces before and after use of Tru-D.

Results: On inoculated surfaces, application of Tru-D at a reflected dose of 22,000 microWs/cm(2) for approximately 45 minutes consistently reduced recovery of C. difficile spores and MRSA by >2-3 log10 colony forming units (CFU)/cm2 and of VRE by >3-4 log10 CFU/cm(2). Similar killing of MRSA and VRE was achieved in approximately 20 minutes at a reflected dose of 12,000 microWs/cm(2), but killing of C. difficile spores was reduced. Disinfection of hospital rooms with Tru-D reduced the frequency of positive MRSA and VRE cultures by 93% and of C. difficile 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 (P < 0.001). The system required <5 minutes to set up and did not require continuous monitoring.

Conclusions: The Tru-D Rapid Room Disinfection device is a novel, automated, and efficient environmental disinfection technology that significantly reduces C. difficile, VRE and MRSA contamination on commonly touched hospital surfaces.

Figure 1

Picture of the Tru-D device placed inside a hospital room.

Figure 2

Mean reduction (log₁₀colony-forming units [CFU]/cm²) in recovery of multiple strains of Clostridium difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) from laboratory bench top surfaces after the use of the Tru-D device. For each pathogen, the inoculum applied to the bench top was adjusted such that 10³ to 10⁵ CFU were recovered from the positive control specimens. The Tru-D device was operated at a reflected dose of 22,000 μWs/cm² for ~45 minutes.

Figure 3

Mean reduction (log₁₀colony-forming units [CFU]/cm²) in recovery of 3 strains of Clostridium difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) from laboratory bench top surfaces after the use of the Tru-D device at reflected doses ranging from 5,000 to 22,000 μWs/cm².

Figure 4

Mean number of colony-forming units (CFU) of Clostridium difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) recovered from contaminated surfaces in hospital rooms before and after disinfection with the Tru-D device. Two-hundred sixty-one total surfaces from 66 rooms were cultured, including call lights, bedside tables, telephones, and bed rails.