2024 Bangladesh Floodwaters Harbour Regional Hotspots of Pathogens and Antimicrobial Resistance.

Seasonal flooding in Bangladesh poses severe public health risks through waterborne disease, yet a comprehensive, genomic-level understanding of the associated microbial hazards is lacking. This study presents a comprehensive shotgun metagenomic analysis of floodwaters from four districts of Bangladesh (Cumilla, Feni, Lakshmipur, and Noakhali) during the devastating 2024 floods, profiling the distribution of pathogenic bacteria, antimicrobial resistance genes, and virulence factors. A total of 12 samples were collected during peak flooding periods and processed using Illumina sequencing. Taxonomic profiling and resistome analysis were performed using MetaPhlAn4, ABRicate, and MEGAHIT, referencing the NCBI and CZ ID databases. Across all regions, 301 operational taxonomic units were identified. Feni exhibited the highest diversity of pathogenic species, including multidrug-resistant Klebsiella pneumoniae, toxigenic Pseudomonas aeruginosa, and mobilizable resistance plasmids (e.g., IncP1, Col440I). Noakhali samples revealed co-detection of zoonotic and emerging pathogens such as Aliarcobacter spp. and Streptococcus suis, along with key resistance genes like blaOXA and ermB. Microbial community clustering revealed strong spatial heterogeneity. This study provides genomic evidence that floodwaters harbour emerging pathogens and AMR. It strongly advocates for incorporating metagenomic tools into Bangladesh's national flood response and AMR monitoring frameworks.