Inactivation efficiency of plasmid-encoded antibiotic resistance genes during water treatment with chlorine, UV, and UV/HO.

This study assessed the inactivation efficiency of plasmid-encoded antibiotic resistance genes (ARGs) both in extracellular form (e-ARG) and present within Escherichia coli (intracellular form, i-ARG) during water treatment with chlorine, UV (254 nm), and UV/HO. A quantitative real-time PCR (qPCR) method was used to quantify the ARG damage to amp (850 bp) and kan (806 bp) amplicons, both of which are located in the pUC4K plasmid. The plate count and flow cytometry methods were also used to determine the bacterial inactivation parameters, such as culturability and membrane damage, respectively.