title: Anaerobic ammonium-oxidizing bacteria gain antibiotic resistance during long-term acclimatization.
abstract: Three broad-spectrum antibiotics, amoxicillin (AMX), florfenicol (FF) and sulfamethazine (SMZ), that inhibit bacteria via different target sites, were selected to evaluate the acute toxicity and long-term effects on anaerobic ammonium oxidation (anammox) granules. The specific anammox activity (SAA) levels reduced by approximately half within the first 3 days in the presence of antibiotics but no nitrite accumulation was observed in continuous-flow experiments. However, the SAA levels and heme c content gradually recovered as the antibiotic concentrations increased. Extracellular polymeric substances (EPS) analysis suggested that anaerobic ammonium-oxidizing bacteria gradually developed a better survival strategy during long-term acclimatization, which reduced the antibiotic stress via increased EPS secretion that provided a protective 'cocoon.' In terms of nitrogen removal efficiency, anammox granules could resist 60 mg-AMX L(-1), 10 mg-FF L(-1) and 100 mg-SMZ L(-1). This study supported the feasibility of using anammox granules to treat antibiotic-containing wastewater.
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Zheng-Zhe
authors.initials: ZZ
authors.lastname: Zhang
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Qian-Qian
authors.initials: QQ
authors.lastname: Zhang
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Guo
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Qian-Qian
authors.initials: QQ
authors.lastname: Chen
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Jiang
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China. Electronic address: jrczju@aliyun.com.
authors.forename: Ren-Cun
authors.initials: RC
authors.lastname: Jin
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D064751:Ammonium Compounds / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001421:Bacteria, Anaerobic / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects; D024881:Drug Resistance, Bacterial / Q000502:physiology*; D010084:Oxidation-Reduction; D011135:Polysaccharides, Bacterial / Q000378:metabolism
chemical_list: D064751:Ammonium Compounds; D000900:Anti-Bacterial Agents; D011135:Polysaccharides, Bacterial
keywords: Acclimatization; Anammox; Antibiotic resistance; Extracellular polymeric substances; Inhibition