Growth and Antibiotic Resistance Acquisition of Escherichia coli in a River That Receives Treated Sewage Effluent

摘要

Wastewater treatment plants could discharge Escherichia coli and antibiotic-resistant bacteria to the environment. However, their discharge also contains nutrients which could promote the growth of E. coli. This study was done to clarify the potential of growth and antibiotic resistance acquisition of E. coli in a river environment. River water, periphyton, and sediment samples were collected at upstream and downstream of treated sewage inflow. Concentrations of E. coli and Chlorophyll increased in river water and periphyton at the downstream, likely due to nutrient input from the treated sewage. Based on pulsed-field gel electrophoresis, identical genotype occurred at multiple sites both upstream and downstream. Multidrug-resistant E. coli strains and non-resistant strains with identical PDGE genotype to the multi-drug strains were detected in periphyton and sediment samples collected at the downstream. These results suggest that the wastewater treatment inflow did not directly provide E. coli to the river water, but could promote the growth of periphyton, which leads to the elevated levels of E. coli and the emergence of antibiotic resistant E. coli.