Scriptiebank overzicht

The environmental microbiome plays a well-established role in influencing human health. While bacterial communities associated with hospital sinks have been extensively documented due to their relevance in infection control, the microbiome of sinks in non-clinical, domestic settings remains comparatively underexplored.
Therefore, the ongoing POEMBAKterie project in our research group aims to characterise the microbial composition of household kitchen sinks in Antwerp. In this thesis, a citizen science approach was employed to collect household kitchen sink samples and associated household metadata as part of the POEMBAKterie project.
Full-length 16S rRNA gene sequencing was performed to characterise bacterial community composition at high taxonomic resolution. In addition, cultivation-based methods using selective media were applied to detect viable opportunistic bacteria, with a focus on the detection of Escherichia coli. Sequencing data were analysed to assess
bacterial community composition, alpha and beta diversity and differences between sample types and households.
Sequencing revealed diverse microbial communities dominated by the phyla Pseudomonadota, Actinomycetota, Bacillota and Bacteroidota, consistent with previously described built-environment microbiomes. At the genus level, taxa such as Microbacterium, Acinetobacter, Paracoccus, Pseudomonas, Moraxella and Stenotrophomonas were most abundant, many of which have previously been associated with water systems, food-related environments, and human microbiota. Significant differences in bacterial community composition were observed between sample types, although substantial overlap and within-group variability were present. In contrast, variation between household locations was limited, likely due to the small sample size. Potential opportunistic bacterial taxa, including E. coli, were detected through both sequencing and cultivation-based approaches. However, overlap between the two methods was only partial, highlighting methodological differences related to viability assessment and methodological sensitivity. Importantly, the presence of these taxa alone is insufficient to infer pathogenicity or infection risk.
Overall, these findings indicate that kitchen sinks represent complex microbial ecosystems shaped by multiple environmental and human inputs and demonstrate the value of combining sequencing and cultivation to characterise both microbial diversity and viability.

Mijn scriptie richt zich op het optimaliseren van forensische DNA-databanken, specifiek hoe DNA-matches beter kunnen worden beoordeeld in gevallen waar de overeenkomst niet volledig duidelijk is, oftewel de ‘grijze zone’. Er werd onderzocht of de toepassing van likelihood ratios (LR) als een alternatieve methode gebruikt kan worden om de betrouwbaarheid van DNA-matches te verbeteren.

In deze studie verricht men genetisch onderzoek op het Heideblauwtje in Vlaanderen. Dit onderzoek kadert binnen het behoud van de biodiversiteit en van bedreigde soorten in Vlaanderen.