# Deciphering the microbiota compositions of complex biofilms from hospital and domestic settings across Estonia, Germany, and the United Kingdom

## TL;DR

This study explores the microbial makeup of drain biofilms in hospitals and homes across three countries, aiming to understand health risks and develop control strategies.

## Contribution

A novel in vitro biofilm model and NGS were used to characterize microbial communities in drain biofilms.

## Key findings

- The study characterized bacterial, fungal, and yeast populations in drain biofilms using NGS.
- A VSEARCH-based clustering approach enabled detailed microbial community analysis.
- Findings provide insights into microbiota abundances and potential interventional measures.

## Abstract

Currently, there is a limited understanding of the microbiota composition of complex biofilms, in particular describing the abundance of bacterial genera, fungi, and yeasts with reference to the One Health axes. As a starting point, describing the microbiota found in these settings would begin to describe the nature of any biological hazards present and facilitate development of strategies to limit transmission and the spread of infection. Furthermore, using this approach, suitable interventional measures could then be tested in the laboratory-scale model for their efficacy and then applied in situ. COMplex Biofilms and AMR Transmission (COMBAT) is a consortium of research teams that studied the application of next-generation sequencing (NGS) strategies to identify bacterial, fungal, and yeast species present in selected biofilms recovered from drain settings found in domestic and hospital settings in four geographical regions. Findings from this study extended our understanding of the bacterial, fungal, and yeast abundances in these sample biofilms and how they may change following enrichment. A VSEARCH-based high-resolution clustering approach was implemented to full-length 16S rRNA (FL-16S) sequencing reads to generate near-ASV operational units, enabling detailed characterization of the microbial communities within complex biofilms. This analytical framework provides the basis for testing interventional measures at the laboratory scale that could be implemented to reduce risk to the One Health axes.

In this study, a novel in vitro biofilm model, mimicking a drain trap, and next-generation sequencing, were employed to characterize the bacterial, fungal, and yeast populations within drain biofilms.