Elena Hacker

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B5 Analysis of virulence factors of Corynebacterium diphtheriae

Principal investigator
Andreas Burkovski

Mentor
Anja Lührmann

PhD exam: 07.03.2016

Characterization of Corynebacterium ulcerans virulence factors

Corynebacterium ulcerans is a pathogenic species of the genus Corynebacterium and closely related to the human pathogen Corynebacterium diphtheriae and the veterinary pathogen Corynebacterium pseudotuberculosis. C. ulcerans is mainly associated with mastitis in cattle, non-human primates and other animals and is also known as commensal in various domestic and wild animals. However, during the last decade, human infections associated with C. ulcerans appear to be increasing in various countries and can most often be ascribed to zoonotic transmission. Besides respiratory diphtheria-like illness, C. ulcerans can also cause extrapharyngeal infections in humans, including severe pulmonary infections. Diphtheria caused by C. ulcerans occurs due to the fact that this species may harbor lysogenic β-corynephages coding for the diphtheria toxin. Besides the diphtheria toxin, there are additional factors contributing to the virulence of this bacterium, like a dermonecrotic toxin with similarity to phospholipase D from C. pseudotuberculosis and a Shiga-like toxin. Only recently, the complete genome sequence of two C. ulcerans strains, named BR-AD22 and 809, was determined. Aim of this thesis is to characterize virulence mechanisms of these two bacterial strains. For this purpose, insertion mutagenesis studies will be carried out in order to analyze the contribution of these virulence factors to the pathogenicity of the bacterium. The ability of mutants compared to the wild type strains to adhere to eukaryotic cells as well as to invade into them will be investigated.

Figure: Scanning electron microscopy C. ulcerans adhered to D562 cell, human pharyngeal carcinoma cells.

 

Publications

Hacker, E., Ott, L., Schulze-Luehrmann, J., Lührmann, A., Wiesmann, V., Wittenberg, T., & Burkovski, A. (2015). The killing of macrophages by Corynebacterium ulcerans. Virulence 2015 Dec 2:1-11, doi: 10.1080/21505594.2015.1125068. [Epub ahead of print]

Antunes, C. A., Clark, L., Wanuske, M. T., Hacker, E., Ott, L., Simpson-Louredo L., , das Gracas de Luna M., Hirata, R., Jr., Mattos-Guaraldi, A. L., Hodgkin J., & Burkovski, A. (2015). Caenorhabditis elegans star formation and negative chemotaxis induced by infection with corynebacteria. Microbiology 2015 Oct 20. doi: 10.1099/mic.0.000201. [Epub ahead of print]

Hacker, E., Ott, L., Hasselt, K., Mattos-Guaraldi, A. L., Tauch, A. & Burkovski, A. (2015). Colonization of human epithelial cell lines by Corynebacterium ulcerans from human and animal sources. Microbiology 161, 1582-1591.

Antunes, C. A., Sanches Dos Santos, L., Hacker, E., Köhler, S., Bösl, K., Ott, L., de Luna, M., Hirata, R., Jr., Azevedo, V. A., Mattos-Guaraldi, A. L. & Burkovski, A. (2015). Characterization of DIP0733, a multi-functional virulence factor of Corynebacterium diphtheriae. Microbiology 161, 639-647.

 

Presentations

October 2015 2nd International SFB 796 Conference: Mechanisms of microbial host cell manipulation: From plants to humans, Erlangen, Germany
”Interaction of Corynebacterium ulcerans with macrophages”
Poster
     
July 2015 7th Annual Retreat, Erlangen School of Molecular Communication, Schloss Hirschberg, Beilngries, Germany
”Interaction of Corynebacterium ulcerans with host cells”
Talk
     
October 2014 66. Jahrestagung der Deutschen Gesellschaft für Hygiene und Mikrobiologie (DGHM) e.V., Dresden, Germany
”Interaction of Corynebacterium ulcerans with macrophages”
Poster
     
July 2014

6th Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
” Interaction of Corynebacterium ulcerans with macrophages”

Talk
     
July 2013 5th Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
Interaction of Corynebacterium ulcerans with macrophages
Talk
     
March 2013 Vereinigung für allgemeine und Angewandte Mikrobiologie, Bremen Germany
Interaction of Corynebacterium ulcerans with macrophages
Poster
     
September 2012 64. Jahrestagung der Deutschen Gesellschaft für Hygiene und Mikrobiologie e.V., Hamburg, Germany
Characterization of virulence factors of Corynebacterium ulcerans
Poster
     
July 2012 4th Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
Virulence of Corynebacterium ulcerans
Poster
     
October 2011 First International SFB 796 Conference: Mechanisms of viral host cell manipulations: from plants to humans, Bamberg, Germany
Characterization of virulence factors of Corynebacterium ulcerans
Poster
     
July 2011 3rd Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
Characterization of virulence factors of Corynebacterium ulcerans
Poster