TY - JOUR

T1 - Extended-Spectrum β-Lactamase and Carbapenemase Genes are Substantially and Sequentially Reduced during Conveyance and Treatment of Urban Sewage

AU - Li, Liguan

AU - Nesme, Joseph

AU - Quintela-Baluja, Marcos

AU - Balboa, Sabela

AU - Hashsham, Syed

AU - Williams, Maggie R.

AU - Yu, Zhuofeng

AU - Sørensen, Søren J.

AU - Graham, David W.

AU - Romalde, Jesús L.

AU - Dechesne, Arnaud

AU - Smets, Barth F.

PY - 2021

Y1 - 2021

N2 - 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.

AB - 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.

U2 - 10.1021/acs.est.0c08548

DO - 10.1021/acs.est.0c08548

M3 - Journal article

C2 - 33886308

VL - 55

SP - 5939

EP - 5949

JO - Environmental Science & Technology

JF - Environmental Science & Technology

SN - 0013-936X

IS - 9

ER -