Infection
Biology / Bacterial pathogenesis
Our group is not only interested in the metabolism of soil microbes and its regulation for industrial applications but also active in understanding how pathogenic bacteria are able to infect and make a living (persist) in the human host and in clinical environments. A couple of years ago we have started to unravel the life style of Acinetobacter baumannii, an emerging pathogenic bacterium. Although A. baumannii infections have been sporadically reported over the decades it has now set up to conquer the world. It already ranks among the top 10 threads of bacterial pathogens. It is able to grow in the eukaryotic cell, to move on solid surfaces, it adheres to surfaces and can survive for a long time on dry surfaces, prerequisites for a survival in the hospital environment. Moreover, it can take up DNA from the environment, integarte the new DNA into its genome and gain new features. Among those are its multidrug resistance. A. baumannii belongs to the group of ESKAPE organisms that escape antibiotic treatment. The drastic increase in A. baumannii infections has led the German Science Foundation (Deutsche Forschungsgemeinschaft) to install an interdisciplinary group of researchers headed by Prof. Volker Müller to unravel the molecular basis of infection and persistence of A. baumannii with the aim to find ways to combat this threatening pathogen (For information on the research unit see http://www.bio.uni-frankfurt.de/51172482/ForschergruppeFOR2251)
In our project we will unravel the molecular basis of the extreme desiccation resistance of A. baumannii. We have used biochemical, genetic and molecular techniques to establish that a non-pathogenic twin of A. baumannii, Acinetobacter baylyi, accumulates compatible solutes to prevent water loss under dry stress. Among those are glycine betaine, glutamate and mannitol. We have identified the genes encoding the enzymes involved in solute accumulation. These genes are also present in A. baumannii and we are under way to delete the genes and study the phenotype of the mutants with respect to their ability to survive dry stress, but we will also study their capabilities to infect and persist in human cells. This will be done in cell cultures and eukaryotic model organisms like Galleria mellonella. In addition we will sequence the genomes of strains obtained from infected patients. By bioinformatics analyses followed by functional genome analyses new virulence traits will be identified.
Cellular adaptation of A. baylyi to low water activities. TCA, citric acid cycle; MtlD, mannitol-1-phosphatase.