Prevalence of Antibiotic Resistance Genes and Their Association with Antibiotics in a Wastewater Treatment Plant: Process Distribution and Analysis

Abstract

Effluents from wastewater treatment plants has been identified as a main point-source of antibiotics and antibiotic resistance genes in natural water environments. In this study, a typical municipal sewage treatment system in south China was taken as the research object to investigate the effects of each treatment unit on eight target antibiotics (sulfamethoxazole, sulfamethazine, tetracycline hydrochloride, oxytetracycline dihydrate, norfloxacin, ofloxacin, clarithromycin, roxithromycin), 17 antibiotic resistance genes (ARGs) and class 1 integron genes in the system using Accelerated Solvent Extraction-Solid phase extraction-Ultra high Performance Liquid Chromatography-Tandem mass spectrometry (ASE-SPE-UPLC-MS/MS) and real-time fluorescent quantitative PCR (qPCR) and the correlation between them. Seven antibiotics (mainly sulfonamides and tetracyclines, 4.19–141.97 ng·L−1) were detected in the influent, while only sulfamethoxazole, sulfamethazine, ofloxacin, and clarithromycin were detected in the effluent (3.11–16.61 ng·L−1). The tetracycline antibiotics in the wastewater treatment plant (WWTP) were transferred to the sludge phase by adsorption, in which tetracycline hydrochloride and oxytetracycline dihydrate were mostly removed in the aerobic and anaerobic stages, while sulfamethoxazole was mainly removed through biological transformation. Sul I was the most abundant resistance gene, but the WWTP had no obvious effect on its removal. Anaerobic treatment was found to play an important role in tetA, tetQ, and tetX removal. Moreover, correlation analysis revealed that the relative abundance of tetX was significantly correlated with clarithromycin (p = 0.039) and ofloxacin (p = 0.028), while that of tetQ was significantly correlated with sulfamethazine (p = 0.007) and sulfamethoxazole (p = 0.001), and that of tetC was significantly correlated with the class 1 integron gene (p = 0.014). Overall, the results presented herein provide a reference for improving the antibiotics and ARGs removal efficiency of WWTPs in south China.

Tetracycline Induces the Formation of Biofilm of Bacteria from Different Phases of Wastewater Treatment

“…Higher abundance of the tetW gene could be associated with higher tetracycline levels in wastewater from the sedimentation tank. A similar result was obtained in the study by Liu et al (2019), in which the relative abundance of the tet genes increased from an anaerobic tank to a secondary settling tank of the WWTP in southern China [49].…”

Resistant Genes and Multidrug-Resistant Bacteria in Wastewater: A Study of Their Transfer to the Water Reservoir in the Czech Republic

“…However, in sampling campaigns A and C, there was a slight increase in the relative abundance of the tetW gene in the sedimentation tanks of the WWTP (Figure 3). Increasing the amount of the tet gene from the anaerobic tank to the secondary settling tank of the WWTP has previously been found by Liu et al (2019) [46].…”

Biosolids for safe land application: does wastewater treatment plant size matters when considering antibiotics, pollutants, microbiome, mobile genetic elements and associated resistance genes?

“…The present study provides unique insight into the pollutant load (antibiotics, heavy metals and disinfectants), the microbial community composition and the abundance of RGs and MGEs in biosolids that can be used as organic fertilizers (except for C L and H M ). A selection of antimicrobial RGs and MGEs found in WWTPs or involved in RG dissemination between the environment and humans was analysed (Heuer et al ., 2012 ; Blau et al ., 2018 ; Liu et al ., 2019 ; Wolters et al ., 2019 ). The results of this study underline the role of biosolids as important sources of RGs and MGEs together with potentially selective pollutants.…”