Study of the abundance and diversity of pipolins in Staphylococcus spp. and characterisation of their gene transfer and antibiotic resistance potential

Details

Supervisors

Gillis, Annika

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en sciences agronomiques, à finalité spécialisée

Abstract

The discovery of a new family B polymerase called primer-independent polymerase B (piPolB) in different phyla has paved the way to a wide range of research opportunities. Indeed, piPolB has de novo synthesis capacity and is encoded in diversified mobile genetic elements called pipolins. This study evaluates the abundance and the diversity of these pipolins in Staphylococcus spp. and characterise their gene transfer and antimicrobial resistance potential. Screenings in Staphylococcus spp. strains from the “Food and Environmental Microbiology (MIAE)” laboratory collection were performed to evaluate the pipolins' occurrence. Subsequently, bioinformatics analyses including genome sequencing and assembly, mapping to references, sequence alignments and protein structure comparisons were performed to investigate pipolins' distribution, diversity, and their potential role in antimicrobial resistance potential. Further, the transformation of a genetic construct into different competent cells is performed to generate in a future work a piPolB knock-out mutant in a pipolin-harbouring Staphylococcus epidermidis strains. The findings of this study offer a substantial contribution to the field by uncovering a novel pipolin, named pGala-11.8, in a Staphylococcus cohnii strain from the MIAE collection, and illustrating the extensive genetic diversity and hardly limited distribution of pipolins in the genus Staphylococcus. Additionally, this work highlights the structural similarities among specific piPolBs in various pipolins, supporting the idea of a shared origin and horizontal gene transfer. Furthermore, the successful development of a genetic construction and its transformation in Staphylococcus cells represent a significant advancement and is promising future to generate piPolB knock-out mutants in pipolin-harbouring Staphylococcus strains These outcomes establish a robust basis for future investigations into Staphylococcus strains containing pipolins. The constraints encountered in this study have paved the way for identifying novel avenues for research. Specifically, it is crucial to search for additional pipolins, delve deeper into the characterisation of their distinct genes, investigate protein-protein interactions within them, and explore their potential roles in antimicrobial resistance in Staphylococcus spp. Furthermore, conducting the piPolB knock-out will enable various experiments that will provide insights into the functions of piPolBs within pipolins and allow to investigate a potential link with antimicrobial resistance. Overall, this master’s thesis marks in molecular microbiology offers valuable insights into the prevalence, distribution, composition, structure, and transfer mechanisms of pipolins across various Staphylococcus species. This study promotes additional exploration of the intricacies of pipolins within the genus Staphylococcus and, more broadly, across other bacterial phyla.