Prevalence of bacterial contamination of touchscreens and posterior surfaces of smartphones owned by healthcare workers: a cross-sectional study

BACKGROUND: Mobile phones used by healthcare workers (HCWs) are contaminated with bacteria, but the posterior surface of smartphones has rarely been studied. The aim of this study was to compare the prevalence of microbial contamination of touchscreens and posterior surfaces of smartphones owned by HCWs. METHODS: A cross-sectional study of smartphones used by HCWs employed at two intensive care units at a Japanese tertiary care hospital was performed. Bacteria on each surface of the smartphones were isolated separately. The primary outcomes were the prevalence of microbial contamination on each surface of smartphones and associated bacterial species. Fisher’s exact test was used to compare dichotomous outcomes. RESULTS: Eighty-four HCWs participated in this study. The touchscreen and posterior surface were contaminated in 27 (32.1%) and 39 (46.4%) smartphones, respectively, indicating that the posterior surface was more frequently contaminated (p = 0.041). Bacillus species and coagulase-negative staphylococci were isolated from each surface of the smartphones. CONCLUSIONS: The posterior surface of a smartphone was more significantly contaminated with bacteria than the touchscreen, regardless of having a cover. Therefore, routine cleaning of the posterior surface of a smartphone is recommended.