High-Efficiency Photodynamic Control of Antibiotic-Resistant Bacteria and Antibiotic-Resistant Genes in Wastewater Using Hydrogel-Decorated Porous Polyurethane Sponges with Metal Nanoparticles

Abstract

The overuse and misuse of antibiotics in hospitals and other healthcare settings can lead to the development and spread of multidrug resistance (MDR) bacteria and water contaminants. In this study, silver nanoparticles (AgNPs)-loaded chitosan (CS)-alginate (AA) hydrogels were prepared to control wastewater MDR bacterial contaminants. CS-AA/AgNP composites strongly inhibited a wastewater MDR Enterobacter tabaci biofilm on membrane surfaces. The effect of AgNP-loaded CS-AA composite hydrogels on the gelation time, swelling ratio, in vitro degradation, and in vitro release properties was investigated. Furthermore, due to their outstanding environmentally friendly superhydrophobicity/superoleophilicity, sponges have proven compelling advantages in the area of water contaminants. Therefore, CS-AA/AgNP composites were coated on polyurethane sponges (PUSs) for disinfection applications in wastewater. CS-AA/AgNP composites and CS-AA/AgNP-coated (5 wt %) PUS exhibited higher photodynamic inactivation (PDI) of E. tabaci under blue LED light. In particular, modified PUS exhibited almost complete inactivation (5.1 log cfu/mL) at 40 min. Furthermore, tetracycline antibiotic degradation efficiency was observed to be 72.91% when the modified PUSs were added to antibiotic-polluted water in the designed reactor. In correlation with the degradation of resistance bacteria and antibiotics, the modified PUS in the designed reactor with PDI effect completely degraded tetracycline antibiotic resistance genes (ARGs) tetA and tetB at 45 min and 60 min, respectively. Specifically, PDI action on the modified PUS effectively degraded ARGs such as sul1, tetA, and tetB by 4.2, 3.2, and 2.9 log reduction (copies/mL), respectively. Excellent removal of ARGs after blue LED treatment indicated that the release of MDR pathogens and free ARGs was effectively controlled by the modified PUS photodynamic reaction. Therefore, the modified PUS can be considered as an alternative approach to remove MDR bacteria and free ARGs in the large-scale photodynamic disinfection process.