Green graphene supported Cu2O-Ag2O S-scheme photocatalyst with high disinfection activity for prevention of urinary tract infection in toilets: A metagenomic analysis

Abstract

Amongst the universal infectious diseases, the urinary tract infection (UTI) is one of the most prevalent bacterial infections. Pathogenic microorganisms causing UTI mainly enter the human body from the unhygienic toilet environment. In this study, a graphene structured material (GSM) supported Cu2O-Ag2O composite was synthesized using the co-precipitation method and its photocatalysis-assisted disinfection performance against UTI-causing pathogens was assessed under LED irradiation. The metagenomic analysis of UTI-causing sites was performed by targeting the 16 S rRNA gene region using Illumina sequencing. The results showed that the common phylum identified in the toilets under study is Proteobacteria (76%) and the most dominating genera identified were Acinetobacteria (33%) and Pseudomonas (26%). 8 × 106 CFU mL−1 of Acinetobacter baumanii, Pseudomonas aeruginosa, and Escherichia coli were completely disinfected using the GSM-Cu2O-Ag2O composite within 30 min under LED irradiation. Enterococcus faecalis and mixed bacterial culture took 40 and 75 min, respectively, for complete inactivation. Holes are the major reactive species responsible for photocatalytic inactivation of bacteria. The structural changes of the cells were observed using scanning electron microscopy which indicates that photocatalytic disinfection caused drastic damage to the bacterial cell walls and it was further substantiated by the measurements of DNA and K+ leakage. The composite displayed complete inactivation, remarkable stability and acceptable reusability even after four consecutive cycles. The green composite, after degradation, is supposed to get sequestered in the natural environment without any persistence and bio-magnification prospects. Its potential use can usher in a new greener alternative to traditional toxic disinfectants like benzalkonium chlorides that can exert adverse impacts on the biological environment including human health.