Effect of antibiotic cocktail exposure on functional disturbance of nitrifying microbiome

• Published in: Journal of hazardous materials 2023-08, Vol.455, p.131571-131571, Article 131571
• Main Authors: Nguyen, Anh H., Oh, Seungdae
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - toxicity; Antibiotic cocktail; bioinformatics; biosorption; Biotransformation; ecotoxicology; microbiome; Microbiota; Nitrification; Nitrites - metabolism; Oxytetracycline; Oxytetracycline - toxicity; Sulfamethoxazole; Sulfamethoxazole - toxicity
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.131571

The present study quantitatively determined the degree and type of functional disturbance in the nitrifying microbiome caused by exposure to a single oxytetracycline (OTC) and a two-antibiotic mixture containing OTC and sulfamethoxazole (SMX). While the single antibiotic had a pulsed disturbance on nitritation that was recoverable within three weeks, the antibiotic mixture caused a more significant pulsed disturbance on nitritation and a potential press disturbance on nitratation that was not recoverable for over five months. Bioinformatic analysis revealed significant perturbations for both canonical nitrite-oxidizing (Nitrospira defluvii) and potential complete ammonium-oxidizing (Ca. Nitrospira nitrificans) populations that were strongly associated with the press perturbation on nitratation. In addition to this functional disturbance, the antibiotic mixture reduced the biosorption of OTC and altered its biotransformation pathways, resulting in different transformation products compared with those produced when OTC was treated as a single antibiotic. Collectively, this work elucidated how the antibiotic mixture can affect the degree, type, and duration of the functional disturbance on nitrifying microbiome and offer new insights into the environmental consequences of antibiotic residues (e.g., their fate, transformation, and ecotoxicity) when present as an antibiotic mixture rather than single antibiotics. [Display omitted] •Mixture of OTC and SMX caused an irreversible disturbance to nitratation.•Nitritation disruption associated with the inhibition of canonical NOB and comammox.•Biosorption of OTC was reduced by 20% in the presence of SMX.•Nitrifying enzyme-facilitated (AMO and HAO) transformation pathways were proposed.•Biodetoxification of the antibacterial agents was successfully achieved.