Viral RNA and infectious influenza virus on mobile phones of influenza patients in Hong Kong and the United States

A cross-sectional study on bacterial contamination on the touchscreens and posterior surfaces of smartphones of emergency department staff

RATIONALE, AIMS AND OBJECTIVES

Cleaning smartphones of healthcare workers (HCWs) is generally recommended; however, most previous studies on bacterial contamination of smartphones assessed touchscreens alone. This study compared the prevalence of bacterial contamination on touchscreens and posterior surfaces of smartphones owned by HCWs.

METHOD

A cross-sectional study of smartphones used by HCWs working at an emergency department (ED) at a Japanese tertiary care hospital was conducted. Bacteria on each surface of the smartphones were isolated separately. Descriptive statistics were used to describe the prevalence of microbial contamination on each surface of the smartphones and the types of associated bacterial species. Fisher's exact test was used to compare dichotomous outcomes.

RESULTS

The smartphones of 40 HCWs working in the ED of a Japanese tertiary care hospital were examined. The touchscreens and posterior surfaces were contaminated in 26 (65.0%) and 36 (90.0%) smartphones, respectively, indicating the posterior surface was more frequently contaminated (p = 0.014). Bacillus species and coagulase-negative staphylococci were most frequently isolated from each surface of the smartphones.

CONCLUSIONS

The posterior surface of a smartphone was more significantly contaminated with bacteria than the touchscreen. Both surfaces of smartphones need to be cleaned to prevent bacterial contamination in healthcare environments.

Environmental dissemination of respiratory viruses: dynamic interdependencies of respiratory droplets, aerosols, aerial particulates, environmental surfaces, and contribution of viral re-aerosolization

During the recent pandemic of COVID-19 (SARS-CoV-2), influential public health agencies such as the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) have favored the view that SARS CoV-2 spreads predominantly via droplets. Many experts in aerobiology have openly opposed that stance, forcing a vigorous debate on the topic. In this review, we discuss the various proposed modes of viral transmission, stressing the interdependencies between droplet, aerosol, and fomite spread. Relative humidity and temperature prevailing determine the rates at which respiratory aerosols and droplets emitted from an expiratory event (sneezing, coughing, etc.) evaporate to form smaller droplets or aerosols, or experience hygroscopic growth. Gravitational settling of droplets may result in contamination of environmental surfaces (fomites). Depending upon human, animal and mechanical activities in the occupied space indoors, viruses deposited on environmental surfaces may be re-aerosolized (re-suspended) to contribute to aerosols, and can be conveyed on aerial particulate matter such as dust and allergens. The transmission of respiratory viruses may then best be viewed as resulting from dynamic virus spread from infected individuals to susceptible individuals by various physical states of active respiratory emissions, instead of the current paradigm that emphasizes separate dissemination by respiratory droplets, aerosols or by contaminated fomites. To achieve the optimum outcome in terms of risk mitigation and infection prevention and control (IPAC) during seasonal infection peaks, outbreaks, and pandemics, this holistic view emphasizes the importance of dealing with all interdependent transmission modalities, rather than focusing on one modality.