Unseen pathogen pathways: the impact of high-touch surfaces in public spaces

Abstract

Background:

Surface contamination via hands plays an important role in pathogen spread in public spaces, particularly where numerous people interact with shared surfaces and objects. This study aimed to identify frequently touched surfaces, examine their interconnections, and evaluate the spread of a surrogate virus in a hotel lobby.

Methods:

In a working hotel lobby (in Arizona, USA) a total of 30 h of observation were performed to identify the surfaces and objects touched by hotel users. The observed area included the lobby entrance, check-in desk and other communal areas. The sequence of touches performed by each observed individual was recorded, from which surface-to-surface interactions and fomite interconnections were determined. An entry doorknob and first floor elevator button were seeded with a bacteriophage (Phi X174) tracer; 4 h later, 25 surfaces were swabbed to determine tracer distribution and contamination levels.

Results:

A total of 324 individuals performed 627 touches of 13 different fomites. The elevator button and front desk counter were the most frequently touched (32% and 22%, respectively). More than half (56%) touched 2 or more surfaces. Touches from the elevator button to other surfaces and from other surfaces to the elevator button made up 50% of all interactions.

From two seeded sites, the tracer spread to 13 surfaces over 4 h. The most contaminated surfaces were tables, counter tops and door handles.

Conclusions:

The significant role of hands in transferring pathogens across frequently touched and highly interconnected surfaces in a hotel lobby was demonstrated through observations and sampling, highlighting the opportunity for hand and surface hygiene interventions to break the chain of infection in this hotel setting. These findings have implications for the optimisation of hygiene interventions in other hotel settings and are also applicable to similar public spaces, where common shared surfaces and objects (such as front desk counters and elevator buttons) could be targeted.

Plain Language Summary

High-touch surfaces in public spaces are connected via hands.

Why was the study done? We wanted to find out what surfaces people are likely to touch in a hotel lobby, and how people are interconnected to each other when their hands touch shared surfaces. Furthermore, we wanted to show how germs can spread in a shared public space by using a harmless microbe.

What did the researchers do? We observed hotel guests in the lobby for a total of 30 h to see what they touched and in what order. We then put a harmless microbe on two surfaces and after 4 h tested surfaces to see where the microbe had spread.

What did the researchers find? Over 30 h, 324 guests made 627 touches of 13 different surfaces. The elevator button and front desk counter were the most frequently touched (32% and 22%, respectively). More than half (56%) touched 2 or more surfaces. 50% of all touches involved the elevator button then other surfaces or other surfaces then the elevator button. The harmless microbe spread via the guests’ hands to 13 other surfaces over 4 h.

What do the findings mean? People are interconnected via their hands through touching surfaces in a shared space. Germs could be spread widely meaning that it is important for timely hygienic cleaning and hand washing to help stop the ‘journey of the germ’.