The fate of sulfonamide resistance genes and anthropogenic pollution marker intI1 after discharge of wastewater into a pristine river stream

Frontiers in Microbiology

Microbiology

Jonas Coelho Kasmanas¹  Ulisses Nunes da Rocha¹  Jochen A. Müller²  Gangan Wang³  Niculina Musat³  Sarah Haenelt³  Florin Musat⁴  Hans Hermann Richnow⁵ 

[1] Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Leipzig, Germany;Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Leipzig, Germany;Institute for Biological Interfaces (IBG 5), Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany;Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research, Leipzig, Germany;Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research, Leipzig, Germany;Department of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeş-Bolyai University, Cluj-Napoca, Romania;Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research, Leipzig, Germany;Isodetect Umweltmonitoring GmbH, Leipzig, Germany;

关键词: class 1 integron;    sulfamethoxazole;    sulfonamide resistance;    sul1;    sul2;    intI1;    river ecosystem;    one health;   

DOI  :  10.3389/fmicb.2023.1058350

 received in 2022-09-30, accepted in 2023-01-10,  发布年份 2023

来源: Frontiers

【 摘 要 】

IntroductionCurrently there are sparse regulations regarding the discharge of antibiotics from wastewater treatment plants (WWTP) into river systems, making surface waters a latent reservoir for antibiotics and antibiotic resistance genes (ARGs). To better understand factors that influence the fate of ARGs in the environment and to foster surveillance of antibiotic resistance spreading in such habitats, several indicator genes have been proposed, including the integrase gene intI1 and the sulfonamide resistance genes sul1 and sul2.MethodsHere we used quantitative PCR and long-read nanopore sequencing to monitor the abundance of these indicator genes and ARGs present as class 1 integron gene cassettes in a river system from pristine source to WWTP-impacted water. ARG abundance was compared with the dynamics of the microbial communities determined via 16S rRNA gene amplicon sequencing, conventional water parameters and the concentration of sulfamethoxazole (SMX), sulfamethazine (SMZ) and sulfadiazine (SDZ).ResultsOur results show that WWTP effluent was the principal source of all three sulfonamides with highest concentrations for SMX (median 8.6 ng/l), and of the indicator genes sul1, sul2 and intI1 with median relative abundance to 16S rRNA gene of 0.55, 0.77 and 0.65%, respectively. Downstream from the WWTP, water quality improved constantly, including lower sulfonamide concentrations, decreasing abundances of sul1 and sul2 and lower numbers and diversity of ARGs in the class 1 integron. The riverine microbial community partially recovered after receiving WWTP effluent, which was consolidated by a microbiome recovery model. Surprisingly, the relative abundance of intI1 increased 3-fold over 13 km of the river stretch, suggesting an internal gene multiplication.DiscussionWe found no evidence that low amounts of sulfonamides in the aquatic environment stimulate the maintenance or even spread of corresponding ARGs. Nevertheless, class 1 integrons carrying various ARGs were still present 13 km downstream from the WWTP. Therefore, limiting the release of ARG-harboring microorganisms may be more crucial for restricting the environmental spread of antimicrobial resistance than attenuating ng/L concentrations of antibiotics.

【 授权许可】

Unknown   
Copyright © 2023 Haenelt, Wang, Kasmanas, Musat, Richnow, da Rocha, Müller and Musat.