Anaerobic ammonium-oxidizing bacteria gain antibiotic resistance during long-term acclimatization

• DOI: 10.1016/j.biortech.2015.06.044
• Publication Date: 2015-06-16T06:38:20Z
• Authors: Zheng-Zhe Zhang; Qian-Qian Zhang; Qiong Guo; Qian-Qian Chen; Xiao-Yan Jiang; Ren-Cun Jin
• Keywords: Bacteria, Anaerobic; Cell Survival; Acclimatization; Ammonium Compounds; Drug Resistance, Bacterial; Polysaccharides, Bacterial; 0211 other engineering and technologies; 02 engineering and technology; Oxidation-Reduction; 6. Clean water; Anti-Bacterial Agents

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.