Effect of sulfidated nanoscale zero-valent iron-activated periodate on bacterial inactivation and conjugative gene transfer

Abstract

Abuse of antibiotics can cause a serious global issue of antibiotic resistance (AR). This research studied the efficiency of sulfidated nanoscale zero-valent iron (S-nZVI)-activated periodate toward the inactivation of antibiotic-resistant bacteria (ARB) and the conjugative transfer of antibiotic resistance genes (ARGs), with E. coli strains HB101 (carrying the RP4 plasmid) and NK5449 as the donor and recipient, respectively. In comparison to the control group (without treatment with S-nZVI/PI), the ARG conjugative transfer frequency within 24 h decreased from 6.3 × 10⁻⁴ to 6.6 × 10⁻⁵ after treatment with the S-nZVI/PI system (S-nZVI = 50 mg L⁻¹, and PI = 1.0 mM) for 40 min. The S-nZVI/PI system functioned as an inhibitor of conjugative transfer for ARGs, which was attributed to the inhibition of the synthesis of the driving-energy adenosine triphosphate (ATP) and prevention of gene expression regarding contact and pairing (traF), assembly of a transmembrane DNA transport channel (trbA), transfer of ssDNA from donor bacteria to recipient bacteria (traG), and global regulation (traJ, korA, and korB). Increasing the dosages of S-nZVI and PI could increase the sterilization of the donor and recipient, while the conjugative transfer of ARGs was less influenced by the S-nZVI and PI dosages. The decline in the initial concentration of the donor and recipient could increase the bactericidal efficiency and decrease the ARG conjugative transfer frequency. HCO₃⁻ and HA existing in the S-nZVI/PI system exhibited inhibitory roles against both bacterial inactivation and ARGs conjugative transfer. The findings of this study could provide a valid alternative for remediating environments contaminated with ARB and controlling the dissemination of AR.