The removal of antibiotic resistant bacteria and antibiotic resistance genes by sulfidated nanoscale zero-valent iron activating periodate: Efficacy and mechanism

• Published in: Environmental research 2023-11, Vol.236 (Pt 2), p.116829-116829, Article 116829
• Main Authors: Liang, Li, Zhang, Guosheng, Dai, Xuening, Li, Weiying
• Format: Article
• Language: English
• Subjects: Antibiotic resistance genes; Antibiotic resistant bacteria; Inactivation; Periodate; Sulfidated nanoscale zero-valent iron
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2023.116829

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have drawn much more attention due to their high risk on human health and ecosystem. In this study, the performance of sulfidated nanoscale zero-valent iron (S-nZVI)/periodate (PI) system toward ARB inactivation and ARGs removal was systematically investigated. The S-nZVI/PI system could realize the complete inactivation of 1 × 108 CFU/mL kanamycin, ampicillin, and tetracycline-resistant E. coli HB101 within 40 min, meanwhile, possessed the ability to remove the intracellular ARGs (iARGs) (including aphA, tetA, and tnpA) carried by E. coli HB101. Specifically, the removal of aphA, tetA, and tnpA by S-nZVI/PI system after 40 min reaction was 0.31, 0.47, and 0.39 log10copies/mL, respectively. The reactive species attributed to the E. coli HB101 inactivation were HO• and O2•−, which could cause the destruction of E. coli HB101 morphology and enzyme system (such as superoxide dismutase and catalase), the loss of intracellular substances, and the damage of iARGs. Moreover, the influence of the dosage of PI and S-nZVI, the initial concentration of E. coli HB101, as well as the co-existing substance (such as HCO3−, NO3−, and humic acid (HA)) on the inactivation of E. coli HB101 and its corresponding iARGs removal was also conducted. It was found that the high dosage of PI and S-nZVI and the low concentration of E. coli HB101 could enhance the disinfection performance of S-nZVI/PI system. The presence of HCO3−, NO3−, and HA in S-nZVI/PI system showed inhibiting role on the inactivation of E. coli HB101 and its corresponding iARGs removal. Overall, this study demonstrates the superiority of S-nZVI/PI system toward ARB inactivation and ARGs removal. The inactivation of E. coli HB101 by sulfidated nanoscale zero-valent iron (S-nZVI) activating periodate (PI). [Display omitted] •S-nZVI/PI system realized the removal of E. coli HB101 and its iARGs.•HO• and O2•− were available reactive species for E. coli HB101 inactivation.•The inactivation mechanism of E. coli HB101 by S-nZVI/PI was revealed.•Co-existing substance could inhibit the sterilization efficacy of S-nZVI/PI.