To the Editor:
The lack of adherence to protocol within the Gostine et al study could threaten the validity of the conclusion about the effectiveness of the ultraviolet-C (UVC) lamps. The large interruption rate (54.6%) raises concerns on how effective the UVC lamps were at sterilization at a shortened interval, which occurred in over half of the instances of keyboard usage.
1
According to Figure 2 of the original article, if the process was interrupted before 5 minutes (time < 5 minutes), there would still be a minimum of 35.44 colony forming units (CFU) on the keyboard, which would be less than the 99.2% reduction of CFU.1
A figure was also not provided for the interruption occurrences at the 90-second delay followed by 6 minutes of the UVC lamp. During these interruptions, the UVC lamps do not achieve full CFU reduction, and the health care workers could increase CFU counts when using the keyboards. A study by Morgan et al found that even with precautionary practices, contamination still occurs 20.5% of the times on gowns and gloves.2
Along with gowns and gloves donning, keyboards are also contacted during this process, causing possible contamination.Gostine et al stated that the UVC lamps were a “novel method for decontaminating high risk devices and surfaces” within the conclusions section.
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The UVC lamp was only evaluated for keyboards, not for other high-touch surfaces, and their results should not be applied to these areas (medical carts and sinks or faucets). These other high-touch areas also have a high contamination rate and should individually be tested for UVC lamp effectiveness. In a study by Bures et al, faucets were found to have been colonized in 15% of occupied rooms, second only to the total percentage of keyboards colonized.3
Because of the lack of knowledge of interruption occurrence after 90-second delays, the conclusions drawn about UVC effectiveness may require further testing. The author should provide figures detailing the interruptions occurring after the 90-second delays and test CFU at the mean time of UVC lamp activation before interruption for all samples. The author should also consider the generalizability of their study more carefully, only applying to surfaces tested within the study.
References
- Evaluating the effectiveness of ultraviolet-C lamps for reducing keyboard contamination in the intensive care unit: a longitudinal analysis.Am J Infect Control. 2016; 44: 1089-1094
- Transfer of multidrug-resistant bacteria to healthcare workers' gloves and gowns after patient contact increases with environmental contamination.Crit Care Med. 2012; 40: 1045-1051
- Computer keyboards and faucet handles as reservoirs of nosocomial pathogens in the intensive care unit.Am J Infect Control. 2000; 28: 465-471
Article info
Publication history
Published online: January 18, 2017
Footnotes
Conflicts of interest: None to report.
Identification
Copyright
© 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
