Microbial diversity, functional genomics and antibiotic resistance in integrated chicken and fish farming systems of Bangladesh

Résumé fourni par la source

The integrated chicken and fish farming system in Bangladesh is widely practiced for its resource efficiency, yet its microbial structure, functional potential, and associated antimicrobial resistance risks remain poorly understood. This study investigated microbial communities, metabolic functions, and antimicrobial resistance profiles across multiple components of integrated farming systems, including chicken gut, chicken droppings, feed, fish intestine, and pond sediment. Microbial profiling was performed using 16S ribosomal ribonucleic acid (rRNA) gene sequencing, functional metagenomic prediction, and culture-based isolation, complemented by antimicrobial susceptibility testing. A total of 2,838 operational taxonomic units were identified, with bacteria constituting the vast majority of detected microorganisms. Microbial community composition was strongly shaped by sample type, reflecting distinct ecological niches within the farming system. Chicken gut samples were dominated by Firmicutes, feed samples by Cyanobacteria, and sediment samples exhibited the highest microbial diversity, including taxa involved in biogeochemical cycling. Functional analysis revealed that pathways related to amino acid and carbohydrate metabolism were most abundant across all samples, while sediment and feed were enriched in pathways associated with xenobiotic degradation, suggesting a role in environmental detoxification. Culture-based methods isolated clinically relevant bacteria, including Escherichia coli and Proteus mirabilis, although metagenomic analysis indicated that these organisms represented only a minor fraction of the overall microbial community. Antimicrobial susceptibility testing demonstrated notable resistance, particularly to tetracyclines and fluoroquinolones. Metagenomic analysis further identified multiple antimicrobial resistance genes, with several showing strong associations with specific bacterial genera. This study provides the first comprehensive characterization of microbial diversity, functional capacity, and antimicrobial resistance within integrated chicken and fish farming systems in Bangladesh, highlighting potential environmental reservoirs of resistance and underscoring the need for improved management strategies to enhance sustainability and reduce public health risks.

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