Inactivation of antibiotic resistant bacteria and genes by conventional and advanced disinfection methods.
Patel, Manisha Sanjay
Master of Science
This research investigates the impact of chlorination, ultraviolet-C (UVC) irradiation, and titanium dioxide photocatalysis (UV-A/TiO2) on the destruction of the multi-drug resistant New Delhi metallo-beta-lactamase (blaNDM-1) gene and the inactivation of Escherichia coli (E. coli) carrying the gene. The blaNDM-1 E. coli was obtained by transferring plasmids carrying the blaNDM-1 gene to the control strain, E. coli K12, and experiments were performed with both the blaNDM-1 E. coli and the untreated E. coli K12. Our results show that the blaNDM-1 E. coli was significantly more resistant to all three disinfection methods especially TiO2 photocatalysis, compared to the non-resistant E. coli K12. blaNDM-1 E. coli achieved a maximum log (C/C0) removal of -2.1, -2.6, and -3.6 whereas E. coli K12 achieved -2.7, -3.4, and -3.9 for chlorine, UVA/TiO2, and UVC. ARG abundances following treatment were not significantly different, whereas microbial inactivation of viable bacteria was. ARG results showcasing higher resistance implies a need to better understand the proliferation of resistant extracellular genes and how to properly control them in wastewater treatment plants. Results from this study can be insightful in optimizing chlorine, UV, and photocatalysis oriented disinfection systems to achieve ARB and ARG reduction.
Disinfection; resistance; bacteria; water