Redistribution of intracellular and extracellular free & adsorbed antibiotic resistance genes through a wastewater treatment plant by an enhanced extracellular DNA extraction method with magnetic beads.

Redistribution of intracellular and extracellular free & adsorbed antibiotic resistance genes through a wastewater treatment plant by an enhanced extracellular DNA extraction method with magnetic beads. Environ Int. 2019 Jul 09;131:104986 Authors: Yuan QB, Huang YM, Wu WB, Zuo P, Hu N, Zhou YZ, Alvarez PJJ Abstract Due to the limitations of current extraction methods, extracellular DNA (eDNA) is rarely discerned from intracellular DNA (iDNA) despite having unique contributions to antibiotic resistance genes (ARGs) propagation. Furthermore, eDNA may be free (f-eDNA) or adsorbed to or suspended solids, including cells (a-eDNA), which affects ARG persistence and transmissivity. We developed a novel method using magnetic beads to separate iDNA, a-eDNA, and f-eDNA to assess how these physical states of ARGs change across a wastewater treatment plant. This method efficiently extracted eDNA (>85.3%) with higher recovery than current methods such as alcohol precipitation, CTAB-based extraction, and DNA extraction kits (<10%). Biological treatment and UV disinfection decreased the concentration of intracellular ARGs (iARGs) and adsorbed extracellular ARGs (a-eARGs), causing an increase of released free extracellular ARGs (f-eARGs). More ARGs were discharged through the wasted biosolids than in the effluent; iARGs and a-eARGs are prevalent in wasted biosolids ((73.9 ± 22.5) % and (23.4 ± 15.3) % of total ARGs respectively),...
Source: Environment International - Category: Environmental Health Authors: Tags: Environ Int Source Type: research