Mobilizable antibiotic resistance genes are present in dust microbial communities

Area of Science:

• Microbiology
• Environmental Health
• Genomics

Background:

• Urbanization increases indoor time, leading to greater exposure to indoor microbes and antibiotic resistance genes (ARGs) in dust.
• Current DNA sequencing methods detect ARGs but don't confirm microbial viability or ARG mobility.
• Assessing the dissemination potential of ARGs in indoor environments is crucial for public health.

Purpose of the Study:

• To investigate the potential for antibiotic resistance gene (ARG) dissemination within indoor dust microbial communities.
• To validate the presence of detected mobile ARGs in viable bacteria found in indoor dust.

Main Methods:

• Integrated 166 dust metagenomes from 43 buildings, assembling and annotating sequences for ARGs and mobile genetic elements (MGEs).
• Utilized cultivation techniques, isolate genome sequencing, and long-read sequencing to confirm ARG presence on mobile elements in viable bacteria.
• Screened for integrons, transposons, and plasmids associated with ARGs.

Main Results:

• Identified 183 ARGs in indoor dust, with 52 found to be potentially mobile (associated with MGEs like plasmids or transposons).
• Confirmed the presence of mobile ARGs in viable dust bacteria, including an ARG on a plasmid from Staphylococcus equorum.
• Demonstrated successful integration of metagenomic and cultivation approaches for ARG analysis.

Conclusions:

• Combining cultivation with metagenomics is a powerful approach to assess the public health risk posed by mobile ARGs in indoor dust.
• Indoor dust microbial communities harbor mobile ARGs with the potential for dissemination.
• Further research is needed to understand the full implications of mobile ARGs in indoor environments.