Molecular epidemiology and pathogenesis of Enterococci
Thursday 16 April 2009
Project
Enterococci are ubiquitous in nature and can be found in soil, water, food, animals and humans. In humans enterococci are natural inhabitants of the gastro-intestinal tract and as such belong to the complex community of bacteria that constitutes the microbiota of the large intestine. Apart from being harmless commensals inhabiting the digestive tract enterococci emerged as the second to third most important nosocomial pathogens the last three decades, with Enterococcus faecium being the Enterococcus species that acquired most antibiotic resistance determinants. Using multilocus sequence typing we demonstrated that hospital associated E. faecium are genotypically distinct from community-associated E. faecium from humans and animals. Using a sequence-based phylogeny we aim to determine the rate of molecular evolution and infer the age of hospital-associated E. faecium. Knowledge on the evolutionary dynamics will also provide an estimate on the number of ecologically distinct populations, within E. faecium. The identification of distinct enterococcal subpopulations is a critical step to understand the genomics and epidemiology of enterococci.
In a second project we aim to use functional genomics-based techniques to provide an explanation to the success of E. faecium in the hospital environment. Using a combination of targeted insertional inactivation of putative virulence genes, analysis of gene expression profile using DNA microarrays under different conditions that mimic infection or colonization by E. faecium and determination of the proteome and secretome in combination with several in vitro (biofilm formation and binding to cell lines and extracellular matrix molecules) and in vivo (experimental infections and colonization in mice) assays, we aim to identify the full repertoire of E. faecium virulence determinants to gain insight in the pathogenesis of E. faecium infections.
Techniques
Molecular biology: i.e. DNA cloning, Conjugation, mutagenesis, PCR including real-time PCR, Sequencing, Southern blotting, Northern blotting; protein purification; flow cytometry; ELISA; gel electrophoreses; Western blotting, adhesion assays to extracellular matrix proteins and cell lines
Duration
6 or 9 months
Contact
Dr. R. Willems, tel. 088 75 576 30, R.Willems@umcutrecht.nl
Dr. H.Snippe, tel. 088 75 576 28, H.Snippe@umcutrecht.nl
More info
Website UMC Utrecht - Medical Microbiology
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