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Extended-Spectrum β-Lactamase and Carbapenemase Genes are Substantially and Sequentially Reduced during Conveyance and Treatment of Urban Sewage

Lookup NU author(s): Marcos Quintela-Baluja, Professor David GrahamORCiD



This is the authors' accepted manuscript of an article that has been published in its final definitive form by American Chemical Society, 2021.

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Urban wastewater systems (UWSs) are a main receptacle of excreted antibiotic resistance genes (ARGs) and their host microorganisms. However, we lack integrated and quantitative observations of the occurrence of ARGs in the UWS to characterize the sources and identify processes that contribute to their fate. We sampled the UWSs from three medium-size cities in Denmark, Spain, and the United Kingdom and quantified 70 clinically important extended-spectrum β-lactamase and carbapenemase genes along with the mobile genetic elements and microbial communities. Results from all three countries showed that sewage-especially from hospitals-carried substantial loads of ARGs (106-107 copies per person equivalent), but these loads progressively declined along sewers and through sewage treatment plants, resulting in minimal emissions (101-104 copies per person equivalent). Removal was primarily during sewage conveyance (65 ± 36%) rather than within sewage treatment (34 ± 23%). The extended-spectrum β-lactamase and carbapenemase genes were clustered in groups based on their persistence in the UWS compartments. The less-persistent groups were associated to putative host taxa (especially Enterobacteriaceae and Moraxellaceae), while the more persistent groups appeared horizontally transferred and correlated significantly with total cell numbers and mobile genetic elements. This documentation of a substantial ARG reduction during sewage conveyance provides opportunities for antibiotic resistance management and a caution for sewage-based antibiotic resistance surveillance.

Publication metadata

Author(s): Li L, Nesme J, Quintela-Baluja M, Balboa S, Hashsham S, Williams MR, Yu Z, Sorensen SJ, Graham DW, Romalde JL, Dechesne A, Smets BF

Publication type: Article

Publication status: Published

Journal: Environmental Science & Technology

Year: 2021

Volume: 55

Issue: 9

Pages: 5939-5949

Print publication date: 04/05/2021

Online publication date: 22/04/2021

Acceptance date: 09/04/2021

Date deposited: 18/06/2021

ISSN (print): 0013-936X

ISSN (electronic): 1520-5851

Publisher: American Chemical Society


DOI: 10.1021/acs.est.0c08548

PubMed id: 33886308


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Funder referenceFunder name
Joint Programming Initiative-Antimicrobial Resistance grant; DARWIN project 7044-00004B