Introduction
Over 700,000 healthcare-associated infections (HAIs) and 99,000 related deaths occur annually in the United States. Reference Morgan, Lomotan, Agnes, McGrail and Roghmann1,Reference Magill, Edwards and Bamberg2 The healthcare environment is a key contributor to HAI transmission. Reference Weber, Anderson and Rutala3–Reference Warren, Turner and Addison5 Therefore, effective environmental disinfection is critical, yet standard chemical disinfection is limited by compliance and contact time; thus, enhanced disinfection strategies are needed. Reference Rock, Small and Hsu6–Reference Warren, Barrett, Graves, King, Turner and Anderson8
Previously, the Tru-D UV-C system (PDI Healthcare) demonstrated effectiveness in decreasing the incidence of MRSA and VRE in high-risk hospital rooms and hospitalwide incidence of Clostridioides difficile and VRE when used for terminal disinfection without concurrent chlorine-based disinfectants. Reference Anderson, Moehring and Weber9,Reference Anderson, Chen and Weber10 Bathrooms received only indirect UV-C, and run times often exceeded 45 minutes, limiting feasibility.
An improved UV-C delivery system (Tru-D iQ) was developed to improve direct UV-C coverage and reduced disinfection run times. We completed a randomized experimental study to assess whether the Tru-D iQ demonstrated superior disinfection efficacy and operational performance compared with the Tru-D Legacy system after patient discharge.
Methods
Study setting and design
We performed this study in inpatient rooms at Duke University Hospital, a 1 048-bed tertiary care hospital in Durham, North Carolina.
Rooms were randomized 1:1 to intervention (Tru-D iQ) or control (Tru-D Legacy). Randomization was stratified by room size so that once a room of a particular size category was assigned to one device, the next room of that size was assigned to the alternate device to maintain size balance across arms. Both Tru-D iQ and Tru-D Legacy systems use real-time sensors to end cycles once the target fluence is reached, with duration adjusting automatically to room size and reflectivity. Each system employs preset cycles specific to vegetative or spore-forming bacteria. The iQ includes a compact secondary emitter for direct bathroom exposure, while the Legacy uses a single-unit emitter for the main room only. Clinical, laboratory, and statistical staff were blinded to randomization; device operators were not.
Six areas in each study room, three in the main room (bed rails, overbed table, and in-room sink) and three in the patient bathroom (toilet seat, bathroom floor around the base of the toilet, and the bathroom sink) were split in half by left and right sides and randomized to pre and postdisinfection sampling.
Additionally, 10 x 10 cm formica sheets were inoculated with 1 x 104 CFU of USA300 Methicillin-resistant Staphylococcus aureus (vegetative disinfection cycles) or Ribotype 027 C. difficile (spore cycles) and placed in three predetermined locations: medical prep area, computer keyboard, and toilet seat.
Study protocol
Rooms were enrolled immediately following the discharge of a patient on contact precautions and prior to any physical cleaning or chemical disinfection. Each room was randomized to the intervention or control study arm, and sample areas were further randomized by pre and postdisinfection sampling as described above. Any item obstructing sampling, such as linens, were removed. The disinfection cycle was selected according to the pathogen that had required contact precautions for the discharged patient. Inoculated formica sheets were placed at predetermined locations, and the assigned UV-C system was used to disinfect the room. Following disinfection, samples were collected from postdisinfection surfaces and formica sheets.
Microbiological methods
All environmental cultures were obtained using the sponge–stomacher technique as previously described, with homogenates plated onto routine and selective media for clinically important pathogens (CIPs), defined as S. aureus, Enterococcus spp., Enterobacterales, and C. difficile. Species were confirmed via 16S rRNA sequencing. Reference Warren, Turner and Addison5,Reference Warren, Barrett, Graves, King, Turner and Anderson8
Outcomes
The primary outcome was the percent reduction in total contamination, measured in colony-forming units (CFUs), from pre to postdisinfection on environmental surfaces. Results from the intervention arm were compared against results from the control arm. Total room CFUs were determined separately for pre and postdisinfection samples by summing the CFUs from all six sampled surfaces on a given side (eg, all right-side surfaces or all left-side surfaces). For analysis, these six sites together were defined as the “room–bathroom suite,“ while the three main room sites (bedrails, overbed table, and room sink) were grouped as “room“ and the three-bathroom sites (toilet seat, bathroom floor, and bathroom sink) were grouped as “bathroom.“ Secondary outcomes were the percent reduction in CFU counts for CIPs, percent reduction in surfaces positive for CIPs, elimination of inoculated pathogens on formica sheets, and device run time.
Statistical analysis
The Wilcoxon signed-rank test was used to compare overall and CIP CFU percent reduction between study arms, device run time, and the Fisher’s exact test was used to compare proportions of sample areas with CIPs and pathogen elimination on formica sheets. P < .05 was considered to be significant. All statistical tests were two-tailed and performed using SAS, version 9.4M7 (SAS Institute Inc). This study was reviewed by the Duke University Health System Institutional Review Board and received an “exempt” status.
Results
Thirty rooms were enrolled: 16 intervention and 14 control. Of those, 18 received the vegetative cycle (10 intervention, 8 control), and 12 received the spore cycle (6 per group). Overall, 396 samples were collected. In general, predisinfection CFU counts were substantial: 23,845 (IQR 1,958–75,360) in suites, with the bathroom (13,407; IQR 1,353–57,538) and bathroom floor (11,701; IQR 1,079–45,225) most contaminated.
Overall, both arms showed bioburden reduction at the suite, room, bathroom, and surface levels (Table 1). Median percent reduction was generally greater in rooms treated with the Tru-D iQ system compared to the Tru-D Legacy system, though most differences were not statistically significant. Notably, bathroom sinks demonstrated a significantly greater reduction with iQ [83% (IQR 18–100)] compared to Legacy [68% (IQR 30–84); P = .02]. For CIPs, both arms showed reductions, with iQ often greater but not significant. Species-level analysis reported as proportion of positive samples demonstrated variable reductions, with no consistent differences between devices (Table 2).
Table 1. Median (IQR) CFU counts before and after UV-C disinfection by surface type and device
Table 2. Proportion of surfaces positive for clinically important pathogens before and after UV-C disinfection by surface type, device, and species
Inocula were 1.1 × 104 CFU for MRSA and 5.0 × 10 ^ 3 CFU for C. difficile. On average, Legacy reduced MRSA by 8.6 × 104 CFU (96%) compared with 1.09 × 104 CFU (99%) for iQ (p = <.01), while Legacy reduced C. difficile by 1.6 × 102 CFU (3%) compared with 2.0 × 103 CFU (40%) for iQ (P = .02). Additionally, elimination of inoculated pathogens from formica surfaces was more frequent in the intervention arm overall (52% vs 81%; P < .01), and by disinfection cycle; 81% vs 97% (P = .03) for vegetative cycles and 13% vs 44% (P = .03) for spore cycles.
Run times were significantly shorter in the intervention arm overall (42 mins vs 22 mins; P < .01), and by disinfection cycle; 33 minutes vs 16 minutes (P < .01) for vegetative cycles and 54 minutes vs 35 minutes (P < .01) for spore cycles.
Discussion
In this randomized experimental study, both the Tru-D iQ and Tru-D Legacy UV-C systems reduced environmental contamination on high-touch surfaces following patient discharge. The Tru-D iQ system generally achieved greater percent reduction at most sites, significantly so at bathroom sinks, but otherwise showed equivalent reductions. The Tru-D iQ also achieved higher elimination of inoculated pathogens across vegetative and spore cycles, suggesting enhanced performance under controlled conditions. Importantly, the iQ system completed disinfection approximately 20 minutes faster, on average.
Limitations include modest sample size, single-center design, and split-surface sampling, which may not fully represent whole-room efficacy.
In conclusion, the Tru-D iQ UV-C system demonstrated key improvements over the Legacy Tru-D Legacy system. Our findings suggest that the iQ system maintains the Legacy’s efficacy while overcoming prior limitations of bathroom coverage and cycle duration, making next-generation UV-C systems more feasible for routine adoption in acute care settings.
Financial support
This study was supported by PDI Healthcare. PDI had no role in study design, data collection, analysis, interpretation, or manuscript preparation. Dr Turner is supported by a career development award from the NIH (K23AI17794).
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