Parinussa, Maikel (2021) The isolation and exploration of novel Aggregatibacter actinomycetemcomitans bacteriophages. thesis, Dentistry.
Full text available on request.Abstract
Aggregatibacter actinomycetemcomitans is closely associated with the aetiology of local juvenile periodontitis (LJP). LJP often requires antibiotic therapy. However, the increasing development of antibiotic resistance is a major drawback and a big challenge to global health. As a result, renewed interest in bacteriophage therapy is growing. Bacteriophages, also referred to as phages, are viruses that reproduce in prokaryotes resulting in lysis of the host cell which is necessary for phage therapy. Unfortunately, little is known about phages with activity against A. actinomycetemcomitans (Aa-phages). Further research is necessary to utilize the development of potential future application of phage therapy. Therefore, the aim of this study is to assess whether LJP patients harbour Aa-phages, determine the efficacy of Aa-phages in reducing A. actinomycetemcomitans growth and explore the relationship with the presence and colony morphology of A. actinomycetemcomitans. In this pilot study, saliva and subgingival samples of 16 LJP patients were examined for Aa-phages and A. actinomycetemcomitans through soft overlay assays. Furthermore, 11 stock strain cultures and one clinical isolate were analysed for Aa-phages through spot assays. If Aa-phages were detected, its effectiveness in reducing A. actinomycetemcomitans growth would be examined. Using the assays, the relationships between Aa-phages and both the presence of A. actinomycetemcomitans and colony morphology would be assessed. A. actinomycetemcomitans was isolated from one patient sample. No Aa-phages were detected in neither the patient samples nor the stock strain cultures. As a consequence, it was not possible to assess the efficiency of Aa-phages in reducing A. actinomycetemcomitans growth. It was also not possible to reliably determine the relation of Aa-phages with neither the prevalence of A. actinomycetemcomitans nor the colony morphology. However, plaques were found indicating bacteriocin-like substances. Therefore, the relationship between bacteriocin-like substances and colony morphology was assessed. Fisher’s exact test showed a statistically significant association between the susceptibility for these substances and colony morphology (ρ > .001). The complications experienced during Aa-phages isolation and the lack of detected Aa-phages indicate the need for evidence-based standardisation in phage isolation protocols. Furthermore, colony morphology should be taken into consideration when selecting strains for new research on bacteriocin-like substances.
| Item Type: | Thesis (UNSPECIFIED) |
|---|---|
| Supervisor name: | Harmsen, Dr. Ir. H.J.M and Siebers, Drs. T. J. H and Tjakkes, Dr. G.H.E. |
| Faculty: | Medical Sciences |
| Date Deposited: | 21 Feb 2023 13:04 |
| Last Modified: | 24 Feb 2023 14:18 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/3446 |
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