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Updated: Oct 5, 2025
Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
Inhalable antibiotic resistomes emitted from hospitals: metagenomic insights into bacterial hosts, clinical
Dong Wu1,2, Ling Jin1,3, Jiawen Xie1
1Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
Background:
Threats of antimicrobial resistance (AMR) to human health are on the rise worldwide. Airborne fine particulate matter (PM2.5), especially those emitted from hospitals, could serve as a substantial yet lesser-known environmental medium of inhalable antibiotic resistomes. A genome-centric understanding of the hosting bacterial taxa, mobility potential, and consequent risks of the resistomes is needed to reveal the health relevance of PM2.5-associated AMR from clinical settings.
Results:
Compared to urban ambient air PM2.5, the hospital samples harbored nearly twice the abundance of antibiotic resistantance genes (ARGs, ~ 0.2 log10(ARGs/16S rRNA gene)) in the summer and winter sampled. The profiled resistome was closely correlated with the human-source-influenced (~ 30% of the contribution) bacterial community (Procrustes test, P < 0.001), reflecting the potential antibiotic-resistant bacteria (PARB), such as the human commensals Staphylococcus spp. and Corynebacterium spp. Despite the reduced abundance and diversity of the assembled metagenomes from summer to winter, the high horizontal transfer potential of ARGs, such as the clinically relevant blaOXA and bacA, in the human virulent PARB remained unaffected in the hospital air PM samples. The occurring patterns of β-lactam resistance genes and their hosting genomes in the studied hospital-emitting PM2.5 were closely related to the in-ward β-lactam-resistant infections (SEM, std = 0.62, P < 0.01). Featured with more abundant potentially virulent PARB (2.89 genome copies/m3-air), the hospital samples had significantly higher resistome risk index scores than the urban ambient air samples, indicating that daily human exposure to virulent PARB via the inhalation of PM2.5 was ten times greater than from the ingestion of drinking water.
Conclusions:
The significance of AMR in the studied hospital-emitting PM2.5 was highlighted by the greater abundance of ARGs, the prevalence of potentially virulent PARB, and the close association with hospital in-ward β-lactam infections. A larger-scale multi-source comparison of genome-resolved antibiotic resistomes is needed to provide a more holistic understanding to evaluate the importance of airborne AMR from the "One-Health" perspective. Video Abstract.
Insights
Hospital airborne fine particulate matter (PM2.5) carries a higher load of antibiotic resistance genes (ARGs) and potentially virulent bacteria than urban air. This highlights a significant, yet underappreciated, risk of inhaling antibiotic resistance from clinical environments.
Area of Science:
- Environmental Science
- Microbiology
- Public Health
Background:
- Antimicrobial resistance (AMR) poses a growing global health threat.
- Airborne fine particulate matter (PM2.5), particularly from hospitals, is a potential pathway for antibiotic resistomes.
- Understanding the bacterial hosts, mobility, and risks of PM2.5-associated AMR is crucial.
Purpose of the Study:
- To investigate the abundance, characteristics, and risks of antibiotic resistance genes (ARGs) in hospital-derived PM2.5.
- To compare airborne resistomes in hospital settings with urban ambient air.
- To assess the potential health implications of inhaling antibiotic-resistant bacteria (PARB) via PM2.5.
Main Methods:
- Genome-centric analysis of bacterial communities and antibiotic resistomes in PM2.5 samples from hospital and urban environments.
- Metagenomic sequencing to profile antibiotic resistance genes (ARGs) and hosting bacteria.
- Correlation analysis to link resistomes with bacterial communities and clinical AMR data.
Main Results:
- Hospital PM2.5 showed significantly higher ARG abundance compared to urban PM2.5.
- The resistome in hospital PM2.5 was strongly correlated with human-associated bacteria, including potentially virulent ones like Staphylococcus spp.
- High horizontal gene transfer potential of ARGs in virulent bacteria persisted, and hospital PM2.5 resistomes mirrored in-hospital AMR patterns.
- Exposure risk to virulent PARB via inhalation of hospital PM2.5 was ten times higher than via drinking water.
Conclusions:
- Hospital-emitting PM2.5 significantly contributes to airborne AMR due to higher ARG levels and virulent PARB.
- The findings underscore the importance of airborne AMR in clinical settings and the need for a 'One Health' approach.
- Further large-scale studies are recommended to fully assess the impact of airborne AMR.
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