Benard Mware, Gilbert Kibet-Rono, Kennedy Mwangi, Doreen Lugano, Shebbar Osiany, Edward Kiritu, Paul O Dobi, Collins Muli, John Juma, Regina Njeru, Eunice M Machuka, Bernard Bett, Ahmed Ogwell, Edward O Abworo, Tulio de Oliveira, Dishon M Muloi, Sofonías K Tessema, Samuel O Oyola
We characterized the taxonomic composition, relative abundance, and antibiotic resistance genes (ARGs) of wastewater-identified bacterial pathogens across socioeconomically and epidemiologically diverse sewerage catchments in Nairobi, Kenya-a key East African urban city representing a low- and middle-income country (LMIC).
Background: Wastewater and Environmental Surveillance (WES) has become a useful public health tool as an early-warning system revealing emergence/re-emergence of pathogenic diseases and spread of antimicrobial resistance (AMR). We characterized the taxonomic composition, relative abundance, and antibiotic resistance genes (ARGs) of wastewater-identified bacterial pathogens across socioeconomically and epidemiologically diverse sewerage catchments in Nairobi, Kenya-a key East African urban city representing a low- and middle-income country (LMIC). Results: Metagenomic analysis of Nairobi's wastewater revealed distinct bacterial and antimicrobial resistance (AMR) profiles. Campylobacteraceae (52.5% ± 17.9%) and Bacteroidaceae (19.8% ± 9.9%) dominated the communities. While Arcobacter cryaerophilus was ubiquitous, Bacteroides fragilis and A. suis abundances varied by neighborhood socioeconomic status. We detected critical clinical pathogens-including Escherichia coli, Vibrio cholerae, Mycobacterium tuberculosis, and the ESKAPE species-alongside 207 distinct ARGs conferring resistance to 11 antibiotic classes. Both taxonomic and ARG compositions showed high spatial heterogeneity, with maximum variation in low-income areas. Temporal analysis captured shifting pathogen dynamics, and metagenomic abundances for Vibrio cholerae and Klebsiella pneumoniae were validated via qPCR. Conclusions: Our findings underscore the utility of WES as a scalable, non-invasive public health tool. By capturing community-level pathogen composition and AMR dynamics, WES bypasses the limitations of clinical diagnostic access, providing a vital early-warning system for underserved urban populations. To maximize its public health utility, environmental genomic signals must serve as actionable triggers for coordinated One Health responses, including targeted clinical diagnostics, localized antimicrobial stewardship reviews, proactive risk communication, and prioritized sanitation infrastructure upgrades.