Reduction and Control of Antibiotic-Resistance Genes and Mobile Genetic Elements in Tetracycline Livestock Wastewater Treated by Microbial Fuel Cell

Abstract

The removal effects of livestock wastewater dominated by tetracycline antibiotic in microbial fuel cell (MFC) and the fate of antibiotic-resistance genes (ARGs) and mobile genetic elements (MGEs) were evaluated by high-throughput quantitative polymerase chain reaction (PCR). In total, 132 kinds of ARGs and seven kinds of MGEs were detected in the untreated livestock wastewater. A decrease in the number of ARGs and MGEs was observed after MFC treatment, among which MGEs decreased by 71.4%. Chloramphenicol-resistance genes and MGEs both dropped in relative abundance, by 58.6% and 55.5%, respectively. The absolute abundance of sulfonamide-resistance genes fell from 5.9×105copiesL−1 to 3.7×105copiesL−1. Vancomycin-resistance genes (130±10copiesL−1) and beta-lactamase-resistance genes (180±10copiesL−1), on the other hand, were not effectively eliminated. After the tetracycline concentration was increased to 6mgL−1, the chemical oxygen demand (COD) removal rate reached up to 88.8%. The corresponding maximum power density value was 763.695mWm−3. A clear alteration in the microbial community structure was noticed as tetracycline concentrations increased. Illumina sequencing indicated that Pandoraea (12.4%), Chitinophaga (12.8%), Dyella (7.3%), and Chryseobacterium (5.4%) were the dominant genera. They were critical for ensuring the reactor’s stable operation and played a significant role in tetracycline degradation in MFC. Results showed that the MFC system had strong resistance to antibiotic toxicity and high potential to control ARGs. Although MFC’s removal efficiency for high tetracycline concentration was limited in this work, MFC was found to have an essential role in lowering ARGs and limiting horizontal gene transfer.