Photocatalytic disinfection of extended-spectrum beta-lactamase producing Escherichia coli using Alumina/ZnO heterostructures

Abstract

Spread of antibiotic resistant bacteria through water pose severe health risks to society. In this context, a systematic study is reported for photocatalytic removal of multidrug resistant (MDR) Escherichia coli and related genes from water by using Alumina/ZnO heterostructures under visible light. 500 mg/L of the photocatalyst could disinfect approximate to 10(6) CFU/mL of target bacteria in water within 240 min of visible light irradiation. Lipid peroxidation, DNA and protein leakage studies have suggested the compromisation of bacterial cell membrane which was further corroborated from electron microscopy images. MDR Escherichia coli has registered a loss of resistance towards fifteen antibiotics with a down-regulation in the antibiotic resistance genes after exposure to photocatalytic process. Proposed process was also validated for disinfection of MDR Staphylococcus haemolyticus and antibiotic susceptible Escherichia coli. Successful disinfection of fecal coliform was achieved in water samples collected from three major rivers and a waste water treatment plant. The in vivo toxicity study of the treated water on mice model has not revealed any remarkable impact on gut health. With high effectiveness in disinfecting bacteria coupled with biocompatibility of the treated water towards animal model may proffer the present technique as a propitious off-grid water disinfection technique for real-world applications.