The effect of acute amoxicillin exposure on anaerobic microbial communities - activity, ecology and resistome

Bruns-Moore, Melissa (2022) The effect of acute amoxicillin exposure on anaerobic microbial communities - activity, ecology and resistome. PhD thesis, University of Glasgow.

Abstract

Antimicrobial resistant (AMR) genes in water treatment technologies are an issue of global concern. However, the impact of antibiotics on the anaerobic microbial communities within the decentralised wastewater treatment systems such as septic tanks is not well researched. This thesis aims to quantify the effects of an acute shock exposure of amoxicillin on the methanogenic activity, treatment efficacy, and structure of the microbial community in anaerobic granules. The work was conducted using an adapted specific methanogenic assay (SMA) to measure the rate of methane production with additional analytical methods including soluble chemical oxygen demand (sCOD) quantification, next generation sequencing (NGS), and AMR detection using Smart-Chip Real time PCR (quantitative PCR, qPCR) array. This work found that the presence of amoxicillin within the anaerobic microbial communities had measurable effects on the rate of methane production, community assembly, and the concentration of AMR genes within the effluent. However, the influence of amoxicillin on sCOD removal was limited. An additional study was conducted to determine the abiotic decay of amoxicillin within anaerobic culture medium. This study found that the oxygen scavenger L-cysteine has a strong catalytic effect on the decay of amoxicillin. As such, studies assessing the sensitivity of amoxicillin in lab grown cultures should take into account the abiotic decay within the medium used. Overall, the research demonstrates that the impact of pharmaceuticals, such as amoxicillin within decentralised waste treatment systems like septic tanks should be more widely investigated. Although septic tanks are rarely monitored, this work demonstrates that they have the potential to be point sources for the spread of AMR. Furthermore, changes to the microbial community caused by shock exposure to amoxicillin and other pharmaceuticals could lead to septic tank failure and discharge of untreated sewage into the water environment.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: T Technology > TA Engineering (General). Civil engineering (General)
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Supervisor's Name: Connelly, Dr. Stephanie, Sloan, Professor William and Ijaz, Dr. Umer
• Date of Award: 2022
• Depositing User: Theses Team
• Unique ID: glathesis:2022-83247
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 02 Nov 2022 15:00
• Last Modified: 02 Nov 2022 15:01
• Thesis DOI: 10.5525/gla.thesis.83247
• URI: https://theses.gla.ac.uk/id/eprint/83247