National University of Singapore
GENOMIC SURVEILLANCE AND RISK-BASED ASSESSMENT OF ANTIBIOTIC RESISTANCE TRANSMISSION ACROSS TROPICAL AQUATIC ENVIRONMENTS
Abstract
dc:description.abstractAntimicrobial resistance (AMR) transmitted through aquatic environments poses a growing public health threat, yet the genomic mechanisms governing resistance gene flow across interconnected water systems remain poorly understood. This thesis investigates β-lactam resistance transmission across Singapore's tropical aquatic continuum—from hospital sewage and community wastewater to freshwater, aquaculture, and coastal environments—using integrated metagenomic and whole-genome sequencing approaches within a One Health framework. A genome-informed risk-profiling framework was developed to classify antibiotic resistance genes (ARGs) by clinical significance, genetic mobility, and host pathogenicity. Analysis of 557 Escherichia coli and 189 Klebsiella pneumoniae isolates, alongside metagenome-assembled genomes, revealed three distinct ARG transmission trajectories defined by the integrity of the ARG–mobile genetic element–pathogen linkage. High-risk clones (ST131, ST147) carrying clinically significant resistance genes (CTX-M-15, NDM-19) were shared between clinical and sewage sources, while downstream environments showed progressive linkage disruption. These findings establish a scalable surveillance framework identifying priority intervention points for environmental AMR mitigation.
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
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- YUAN QIYI