Antibiotic resistance in high and low nucleic acid content bacteria

Erb, Severin

doi:10.21256/zhaw-25039

Please use this identifier to cite or link to this item: https://doi.org/10.21256/zhaw-25039

Publication type:	Bachelor thesis
Title:	Antibiotic resistance in high and low nucleic acid content bacteria
Authors:	Erb, Severin
Advisors / Reviewers:	Smits, Theo Bürgmann, Helmut Rezzonico, Fabio
DOI:	10.21256/zhaw-25039
Extent:	64
Issue Date:	2020
Publisher / Ed. Institution:	ZHAW Zürcher Hochschule für Angewandte Wissenschaften
Publisher / Ed. Institution:	Winterthur
Language:	English
Subjects:	Antibiotics; Antibiotic resistance; Drinking water; Drinking water treatment; HNA and LNA content bacteria
Subject (DDC):	579: Microbiology 615: Pharmacology and therapeutics
Abstract:	This study focused on the distribution of antibiotic resistance genes (ARGs) in «high nucleic acid (HNA) content bacteria» and «low nucleic acid (LNA) content bacteria» in drinking water treatment plants (DWTPs) with different water sources and treatment steps, and bacterial regrowth within their distribution systems (DWDSs). The aim was to identify potential associations of HNA and LNA content bacteria with antibiotic resistance indicator genes – the class 1 integron-integrase gene intI1 and the ARG sul1. In addition, drinking water facilities with few or no treatment steps were examined to assess whether they could potentially pose a higher risk in case of ARGs or bacterial regrowth and to obtain information on the extent to which flow cytometry (FCM) can contribute to the assessment of microbial risk factors in drinking water. Water samples from three larger and three smaller DWTPs in Switzerland were filtered on 0.45 μm and 0.2 μm filter membranes to investigate HNA and LNA cells with FCM and additionally, to compare the frequency of IntI1 and sul1 in HNA and LNA content bacteria with real-time quantitative polymerase chain reaction (real-time qPCR). Furthermore, real-time qPCR was used for 16S rRNA to monitor bacterial regrowth. FCM proved to be a rapid method for detection and separation of HNA and LNA cells in water samples and will be a good method in further drinking water studies. However, it should be mentioned that FCM will not reveal any effect in UV disinfection, which could give a false impression of the effectiveness of this treatment step. Interestingly, the ARG sul1 has never been detected with real-time qPCR in previously treated samples, whereas it could be detected in river water samples with higher HNA content bacteria. Furthermore, the relative abundances compared to 16S rRNA and the proportions in bacteria with HNA and LNA content showed higher frequencies of intI1 and sul1 in bacteria with HNA content than in LNA content bacteria. Moreover, considering ARGs - when comparing the proportions of gene copies per cell in HNA and LNA content bacteria - it generally resulted that LNA content bacteria had less than 5% of them. These results showed a potential for the possibility that a minimum genome size for carrying an ARG could exist. However, a potentially higher risk of ARGs was not observed in drinking water systems with fewer or no treatment steps, although it was found that the most effective treatment step to reduce HNA content bacteria is by infiltration of surface water into groundwater. In the future, however, these results would need to be further investigated in other studies aiming for a wider range of ARGs.
URI:	https://digitalcollection.zhaw.ch/handle/11475/25039
License (according to publishing contract):	CC BY 4.0: Attribution 4.0 International
Departement:	Life Sciences and Facility Management
Appears in collections:	Bachelorarbeiten Umweltingenieurwesen

Files in This Item:

File	Description	Size	Format
2020_Erb_Severin_BA_UI.pdf		4.32 MB	Adobe PDF	View/Open

Show full item record

Erb, S. (2020). Antibiotic resistance in high and low nucleic acid content bacteria [Bachelor’s thesis, ZHAW Zürcher Hochschule für Angewandte Wissenschaften]. https://doi.org/10.21256/zhaw-25039

Erb, S. (2020) Antibiotic resistance in high and low nucleic acid content bacteria. Bachelor’s thesis. ZHAW Zürcher Hochschule für Angewandte Wissenschaften. Available at: https://doi.org/10.21256/zhaw-25039.

S. Erb, “Antibiotic resistance in high and low nucleic acid content bacteria,” Bachelor’s thesis, ZHAW Zürcher Hochschule für Angewandte Wissenschaften, Winterthur, 2020. doi: 10.21256/zhaw-25039.

ERB, Severin, 2020. Antibiotic resistance in high and low nucleic acid content bacteria. Bachelor’s thesis. Winterthur: ZHAW Zürcher Hochschule für Angewandte Wissenschaften

Erb, Severin. 2020. “Antibiotic Resistance in High and Low Nucleic Acid Content Bacteria.” Bachelor’s thesis, Winterthur: ZHAW Zürcher Hochschule für Angewandte Wissenschaften. https://doi.org/10.21256/zhaw-25039.

Erb, Severin. Antibiotic Resistance in High and Low Nucleic Acid Content Bacteria. ZHAW Zürcher Hochschule für Angewandte Wissenschaften, 2020, https://doi.org/10.21256/zhaw-25039.