J Hosp Infect. 2021 Feb 26:S0195-6701(21)00080-3. doi: 10.1016/j.jhin.2021.02.021. Online ahead of print.
INTRODUCTION: Healthcare environmental surfaces may be contaminated with microorganisms that cause healthcare-associated infections (HCAIs). Special attention is paid to near-patient surfaces but less so for sites outside the patient zone. This paper presents data on keyboard contamination and the risk of pathogen transmission from keyboards.
METHODS: Keyboards from nursing stations in three hospitals and a dental practice were analysed for bacterial contamination. Surfaces were pre-treated to remove planktonic bacteria so that any remaining bacteria were presumed to be associated with biofilm. Bacterial transfer from keyboard keys was studied following wiping with sterile water or sodium hypochlorite. The presence of multidrug resistant organisms (MDRO) was sought using selective culture.
RESULTS: Moist swabbing did not detect bacteria from any keyboard samples. Use of enrichment broth, however, demonstrated MDRO from most samples. Gram-negative bacteria were recovered from almost half (45%) samples, with methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococcus and MDR-Acinetobacter from 72%, 31% and 17% of samples, respectively. Isolates were transferred from 69% samples after wiping with sterile water, and from 54% samples after wiping with 1,000 ppm sodium hypochlorite.
DISCUSSION: While moist swabbing failed to detect bacteria from keyboards, pathogens were recovered using enrichment culture. Use of water or NaOCl-soaked wipes transferred bacteria from most samples tested. Our study implies that hospital keyboards situated outside the patient zone, commonly harbour dry surface biofilms (DSB) that offer a potential reservoir for transferable pathogens. While the role of keyboards in transmission is uncertain, we should pursue effective solutions for eliminating DSB from keyboards.