The effectiveness of continuous UV-C disinfection robots compared with pulsed xenon (PX-UV) models has been highlighted in a recently published study of ultraviolet (UV) light disinfection systems by an infection prevention research team.
The study, reported in the journal Infection Control & Hospital Epidemiology, tested a continuous UV-C robot, which was operated for the same length of time from the same point in the room as a PX-UV unit.
The results showed surprisingly low pathogen kill rates for the PX-UV model – about .5 log for both C.diff and VRE, even as close as 4ft. The continuous UV-C robot had a much higher CFU reduction for the pathogens C.diff, MRSA and VRE.
According to the study, PX-UV was less effective than continuous UV-C in reducing pathogen recovery on glass slides with a 10-minute exposure time in similar hospital rooms and the UV-C device achieved 'significantly greater log10 CFU reductions'. Not only did the continuous UV-C robot show much stronger disinfectant results, but also it was not run for its entire cycle time.
PX-UV was less effective than continuous UV-C in reducing pathogen recovery on glass slides with a 10-minute exposure time
The study drew attention to the dangers of trying to complete a disinfectant procedure too quickly and under-dosing as a result. Although the PX-UV device reduced contamination on surfaces, residual contamination was not uncommon, the study found.
Tom Kenny, CEO of Infection Prevention Technologies, a US supplier of UV-C robots, said: 'In an effort to speed up the cleaning process, EVS and IP staff may be misleading themselves about how well the pulsed xenon treated rooms are really disinfected.
'Hospitals must be wary of bold claims of speed and efficacy made by manufacturers of pulsed xenon units that simply don’t stand up to scrutiny as clearly shown in the study.'
Kenny added: 'IPT’s IRiS 3200m is more than twice as powerful as the continuous UV-C device in the study and 25 times more powerful than the PX-UV unit. Given that the PX-UV unit has to be moved around several times just to treat a single room, it really debunks the myth that these units are faster than continuous UV-C robots.'
According to Kenny, IPT's IriS robots employ real-time Smart-Dose UV-C technology to determine how long to treat a room taking the guesswork away from the hospital staff.
'Guessing how long to run your UV-C system is not good science,' he said. 'Unless you are measuring the UV-C dosage in real-time with UV sensors you may be under-dosing the room.'
The study also found that the effectiveness of PX-UV was dramatically reduced as the distance from the device was increased. The net effect is that PX-UV devices require multiple treatments in a single room.
The IRiS family use patented 'Power-Boost' and 'Field Balancing' technologies resulting in whole-room treatments and faster treatment times. These power enhancement technologies are designed to enable the IRiS UV-C robots to disinfect even shadow areas in a single treatment without moving the robot around.
The study was funded by the US Veterans Administration.
