Removal of ciprofloxacin and trimethoprim sulfamethoxazole resistant escherichia coli and antibiotic resistance genes in a wastewater treatment plant in Binh Chanh district, Ho Chi Minh city

Abstract

Wastewater is one of the most important reservoirs of antibiotic resistance. The abundance of carbon sources and other nutrients; a variety of possible electron acceptors such as oxygen or nitrate; the presence of particles onto which bacteria can adsorb; a relatively stable pH and temperature are the conditions that favor the remarkable diversity of microorganisms in this unusual habitat. The wastewater microbiome contains bacteria from the environment, humans, and animals, many of which have antibiotic resistance genes (ARGs). The goal of this research is to investigate the incidence of Ciprofloxacin and Trimethoprim/sulfamethoxazole antibiotic resistant E. coli in a wastewater treatment plant in Ho Chi Minh City, which is an excellent habitat for the development and transmission of antibiotic resistant bacteria and genes. The presence and removal of antibiotic-resistant Escherichia coli and genes in an urban wastewater treatment plant were investigated. After various treatment processes in a WWTP in Ho Chi Minh City, Vietnam, wastewater samples were collected at 5 sampling sites. Total E. coli and E. coli resistant to Ciprofloxacin and Sulfamethoxazole/Trimethoprim concentrations were determined using Tryptone Bile Xglucuronide agar supplemented with target antibiotics and confirmed with the indole test. qPCR was used to determine the concentrations of total bacterial 16S rDNA and six antibiotic resistance genes (sul1, sul2, dfrA, aac(6)-Ib-cr, qnrA, qnrB, blaTEM, and blaCTX). The results showed that aeration tank biological treatment and chlorination disinfection effectively eliminated antibiotic resistant E. coli (up to 99.9% from the final effluent), whereas aeration tank and secondary sedimentation significantly removed ARGs and other test genes (up to 99.22% from the final effluent).