Project Number # 2079
Antibiotics have been widely used for human and livestock to treat infectious diseases and promote the growth of livestock (Zhuang et al., 2015). Although the effectiveness of antibiotics has significantly benefited mankind, the intensive use of antibiotics has led to the spread of antibiotic resistance among microorganisms. Antibiotic resistance genes (ARGs), as the main reason for microorganisms to be able to withstand the bacteriostatic or bactericidal effects of antibiotics (Martínez et al., 2014), have been widely found in soil, surface water, groundwater, and even deep ocean sediments (Allen et al., 2010; Brown and Balkwill, 2009; Ouyang et al., 2020). The spread of ARGs not only posed a global threat to the public well-being, but also affected the development of industries such as veterinary medicine and agriculture (Teuber, 2001).
Wastewater treatment plants (WWTPs) have been recognized as the hotspots of ARGs and antibiotic resistance bacteria (ARB) (Mao et al., 2015). The disinfection treatments play an important role as critical barriers to mitigate the transfer of ARGs and ARB (Singer et al., 2016). However, the effect of various disinfection processes on the ARGs diversity and abundance has not been adequately investigated. Therefore, it is quite important to understand the fate of ARGs and ARB under various disinfection processes to identify the optimal disinfection conditions for reducing the spread of antibiotic resistance in Australia.
This project aims to understand and reduce the spread of antibiotic resistance in disinfection. This project will utilize 16S rRNA sequencing, qPCR and metagenomics to uncover the changes in the occurrence, abundance and diversity of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) under various disinfection processes. This study will help identify the optimal disinfection conditions for reducing the spread of antibiotic resistance. In addition, based on the results of this study, the control and management strategy for antibiotic resistance will also be proposed.
This project is significant because it will comprehensively reveal the fate of ARGs and ARB under various disinfection processes and identify the optimal disinfection conditions for reducing the spread of antibiotic resistance. This project will also provide a state-of-the-art approach for accurate estimation of occurrence, diversity, abundance and fate of ARGs.
The project will consist of two interlinked tasks.
Task 1: Changes in the occurrence, abundance and diversity of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in various disinfection processes (Months 1-24)
This task will reveal the changes in the occurrence, abundance and diversity of ARGs and ARB in various disinfection processes.
The water samples before and after various disinfection processes will be collected at different seasons from the water authority which sponsors this project. Afterwards, the occurrence, abundance and diversity of ARGs and ARB will be analysed using the methods described below.
DNA from the water samples will be extracted for 16S rRNA sequencing to uncover the profiles of ARB, and high-throughput qPCR will be applied to determine and quantify the occurrence of typical ARGs for these water samples. These ARGs will include tetracycline resistance genes (tetA, tetG, tetM, tetX, tetQ and tetW), erythromycin resistance genes (ermB and ermF) and sulfonamide resistance genes (sulI and sulII). They were selected according to types of antibiotics and main resistance mechanisms. In addition, some selected mobile genetic elements (MGEs) represent the potential of the horizontal gene transfer, including the class 1 integrase gene (intI1), the conjugative transposon Tn916-Tn1545 family (Tn916/1545) and one insertion sequence common region I gene (ISCR1) will also be quantified to (HGT). Furthermore, some water samples before and after disinfection will also be selected for high-throughput metagenomics. This approach will be applied to investigate the fate of the broad-spectrum profiles of ARGs in disinfection.
Task 2: Control and management strategy for antibiotic resistance (Months 25-36)
Based on the results of this study, the control and management strategy for antibiotic resistance will also be proposed.
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Australian Government Department of Health Department of Agriculture, Response to the threat of antimicrobial resistance, Australia’ first national antimicrobial resistance strategy, 2015-2019. ISBN: 978-1-76007-191-2.
Brown, M.G., Balkwill, D.L., 2009. Antibiotic resistance in bacteria isolated from the deep terrestrial subsurface. Microb. Ecol. 57 (3), 484.
Mao, D., Yu, S., Rysz, M., Luo, Y., Yang, F., Li, F., Hou, J., Mu, Q., Alvarez, P.J.J. 2015. Prevalence and proliferation of antibiotic resistance genes in two municipal wastewater treatment plants. Water Res., 85, 458-466.
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Zhuang, Y., Ren, H., Geng, J., Zhang, Y., Zhang, Y., Ding, L., Xu, K., 2015. Inactivation of antibiotic resistance genes in municipal wastewater by chlorination, ultraviolet, and ozonation disinfection. Environ. Sci. Pollut. Res. 22 (9), 7037-7044.