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Elucidating environmental resistomes using in silico analysis

Dissertation (MSc (Bioinformatics))--University of Pretoria, 2021.

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Other Authors: Makhalanyane, Thulani Peter
Format: Thesis
Language:English
Published: University of Pretoria 2022
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access_status_str Open Access
author2 Makhalanyane, Thulani Peter
author_browse Makhalanyane, Thulani Peter
author_facet Makhalanyane, Thulani Peter
collection Thesis
dc_rights_str_mv © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MSc (Bioinformatics))--University of Pretoria, 2021.
format Thesis
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institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:36:29.578Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2022
publishDateRange 2022
publishDateSort 2022
publisher University of Pretoria
publisherStr University of Pretoria
record_format dspace
source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/83759 Elucidating environmental resistomes using in silico analysis Makhalanyane, Thulani Peter zak.claassen@gmail.com Pierneef, Rian Ewald Claassen, I.C. UCTD Antibiotic resistance (ABR) Antibiotic resistance genes (ARGs) Multidrug efflux Genomic islands Dissertation (MSc (Bioinformatics))--University of Pretoria, 2021. The antibiotic resistance crisis is one of the most significant challenges in healthcare. There is some evidence suggesting that clinical and environmental resistance may be linked via the horizontal acquisition of resistance genes among pathogens derived from the environment. In addition, anthropogenic influence may contribute to resistance in natural environments. Understanding the nexus of interactions among microbial communities including pathogens, their environments and the concomitant increase in antimicrobial resistance genes is a major ecological endeavour. Yet, despite its importance, resistance is understudied in the environment, and there is a clear knowledge deficit regarding the taxonomic distribution and function of these genes in natural environments. To reduce this knowledge deficit, this study aimed to elucidate environmental resistomes using in silico approaches. We predicted antibiotic resistance genes (ARGs) in prokaryotic genomes acquired from the proGenomes database. These genomes were assigned to eight discrete environments. The taxa IDs from the proGenomes database were assigned taxonomic ranks. Genomic islands harbouring ARGs, and phages were also predicted. We also determined the phylogenetic diversity and the extent to which ARGs, and ARG-carrying taxa were overrepresented in some environments. The analysis showed that host associated environments had the highest richness of ARGs, with soils demonstrating the highest diversity levels. Multidrug efflux pumps were the largest resistance group across all habitats, followed by beta-lactamases. The antibiotic classes, to which the highest resistance was conferred, included penams, cephalosporins, tetracyclines, macrolides, aminoglycosides and fluoroquinolones. The analysis suggests that resistance to tetracycline was the most variable, being high in disease and host associated environments, but lower in other categories. All environments had at least one ARG in a large proportion of their species. Proteobacteria has the most ARGs, with the largest proportion found in Gammaproteobacteria. In total, 116 ARGs were shared, but most large groups and resistance to most antibiotics and classes were shared across all habitats. This result suggests that resistance “functions” are present in all environments, although the specific ARGs conferring them were not necessarily shared. ARGs were also found in the predicted genomic islands and bacteriophages. The ARGs in genomic islands appear to be overrepresented in disease and host associated environments, while ARGs in phages are overrepresented in food and host associated, respectively. We found several genes encoding beta-lactamases and aminoglycoside-modifying enzymes in both genomic islands and bacteriophages. Elfamycin resistance appears to be very common in genomic islands, and in general, although this needs to be experimentally confirmed. The results from this study corroborate previous studies albeit with some caveats linked to the difficulties of standardisation and comparisons. Together, the data suggest that resistance is extensive in the environment, with most functions shared but some differences in the relative abundances. Some ARGs were also present in putative genomic islands and phages, suggesting an increased risk for transfer. Despite methodological differences, the results of this study were consistent with previous findings showing common features of the environmental resistome. National Research Foundation (NRF) Genetics MSc (Bioinformatics) Unrestricted 2022-02-10T09:16:22Z 2022-02-10T09:16:22Z 2022-04 2021 Dissertation * A2022 http://hdl.handle.net/2263/83759 en © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle UCTD
Antibiotic resistance (ABR)
Antibiotic resistance genes (ARGs)
Multidrug efflux
Genomic islands
Elucidating environmental resistomes using in silico analysis
title Elucidating environmental resistomes using in silico analysis
title_full Elucidating environmental resistomes using in silico analysis
title_fullStr Elucidating environmental resistomes using in silico analysis
title_full_unstemmed Elucidating environmental resistomes using in silico analysis
title_short Elucidating environmental resistomes using in silico analysis
title_sort elucidating environmental resistomes using in silico analysis
topic UCTD
Antibiotic resistance (ABR)
Antibiotic resistance genes (ARGs)
Multidrug efflux
Genomic islands
url http://hdl.handle.net/2263/83759