The ecological risks posed by incompletely degraded antibiotic intermediates in aquatic environments warrant significant attention. This study investigated the degradation mechanisms of sulfonamides (sulfadiazine, sulfamethoxazole) and quinolones (ciprofloxacin, norfloxacin) during thermally activated persulfate (TAP) treatment. The main degradation mechanisms for sulfonamides involved S-N bond cleavage and –NH2 oxidation mediated by sulfate and hydroxyl radicals, whereas quinolone degradation occurred primarily through piperazine ring cleavage facilitated by a single linear oxygen. Toxic degradation intermediates were found to be enriched with bacteria in real water samples, including Aeromonas (SDZ-50, 9.61%), Acinetobacter (SMZ-50, 21.91%), unclassified Archaea (CIP-50, 19.32%), and Herbaspirillum (NOR-50, 17.36%). Meanwhile, the abundance of sulfonamide-associated antibiotic resistance genes (ARGs) (sul1 and sul2) and quinolone-associated ARGs (mfpA, emrA, and lfrA) significantly increased, with SMZ-50 and NOR-50 reaching 659.34 and 2009.98 RPKM, respectively. Correlation analysis revealed differences in host diversity and composition driven by the same classes of antibiotics and their intermediates.

中文翻译：

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磺胺类药物和喹诺酮类药物降解中间体的生态风险：毒性、微生物群落和抗生素耐药基因


水生环境中未完全降解的抗生素中间体带来的生态风险值得高度关注。本研究探讨了磺胺类药物（磺胺嘧啶、磺胺甲噁唑）和喹诺酮类药物（环丙沙星、诺氟沙星）在热活化过硫酸盐 （TAP） 处理过程中的降解机制。磺胺类药物的主要降解机制涉及硫酸根和羟基自由基介导的 S-N 键裂解和 –NH2 氧化，而喹诺酮类降解主要通过单个线性氧促进的哌嗪环裂解发生。发现真实水样中富含细菌的毒性降解中间体，包括气单胞菌属 （SDZ-50， 9.61%）、不动杆菌属 （SMZ-50， 21.91%）、未分类的古细菌 （CIP-50， 19.32%） 和草本螺旋菌属 （NOR-50， 17.36%）。同时，磺胺类药物相关抗生素耐药基因 （ARG） （sul1 和 sul2） 和喹诺酮类相关 ARGs （mfpA、emrA 和 lfrA） 的丰度显著增加，SMZ-50 和 NOR-50 分别达到 659.34 和 2009.98 RPKM。相关性分析揭示了由同一类抗生素及其中间体驱动的宿主多样性和组成的差异。