# Transmission pathways during high-contact care activities in nursing homes: a high-fidelity simulation study with surrogate markers

## TL;DR

This study uses simulations to show how nursing assistants' care routines can spread infections in nursing homes.

## Contribution

The study introduces high-fidelity simulations with surrogate markers to map transmission pathways during resident care.

## Key findings

- A median of 11.5 transmission events occurred per simulation, mostly within residents' immediate environments.
- Contamination of CNA scrubs and hands accounted for 24% of transmission events, mainly during bed bathing.
- Shared objects like wheelchairs and linen bins contributed to 16% of transmission events.

## Abstract

To understand how the workflows and infection prevention and control (IPC) practices of certified nursing assistants (CNAs) during high-contact resident care activities contribute to multidrug-resistant organism (MDRO) transmission in nursing homes.

We conducted 10 high-fidelity simulations of two high-contact resident care activities, bed bathing and incontinence care, with CNAs from long-term or mixed-care units. Four genetic variants of λ phage were applied to select surfaces prior to simulations and subsequently sampled from the environment, residents, supplies, and CNAs. Simulations were video recorded and analyzed for patterns of hand-to-surface contact and performance of IPC practices, including hand hygiene, personal protective equipment use, and environmental surface cleaning or disinfection.

A median of 11.5 transmission events occurred per simulation. Most events (60%) occurred within residents’ immediate environments, reflecting how CNAs frequently transitioned between a resident, their surroundings, and care supplies, combined with infrequent hand hygiene and surface disinfection. Contamination of CNA scrubs and hands accounted for 24% of events, primarily from bed bathing, which involved frequent contact without a gown. Transmission to shared objects (e.g., linen bin, trash can, wheelchair) accounted for 16% of events and created additional opportunities for transmission between residents. Transmission between residents or their immediate environments was rare but typically associated with workflow disruptions from limited-supply availability.

In high-fidelity simulations of high-contact resident care activities, transmission of surrogate markers for MDROs closely followed the workflows of CNAs. This method identifies potential transmission pathways and interventions for mitigating MDRO spread in nursing homes.