Prof. Dr. Annelies Zinkernagel


The era of antibiotic therapy has greatly reduced morbidity and mortality caused by infectious diseases. However, continuous emergence of resistant bacterial pathogens represents great challenges to human medicine. Against essentially every antibiotic ever developed, resistance has developed. We therefore need alternative approaches to combat such infections. Virulence factors allow bacteria to infect, i.e. to invade into and to persist within the human host. In-depth knowledge of the bacterial virulence factors should help to find ways to specifically neutralize them and render bacteria ‘disarmed’ and thus ‘avirulent’.

Bacterial virulence factors
To circumvent the human immune system, pathogens express a wide array of virulence factors. A better understanding of how these virulence factors work, how they are influenced by the environment as well as whether the presence of antibiotics modulates their activity and expression, is of great importance to fine-tune the therapy against bacterial infections in the best possible way. In particular considering the worldwide increase in antibiotic resistant bacteria, both Gram-positive (e.g. Staphylococci) as well as Gram-negative (e.g. Pseudomonas), requires the establishment of new treatment.

Bacterial persistence in humans
Relapse rates of Staphylococcus aureus infections are high despite in vitro effective antibiotic treatment. The ability of Staphylococcus aureus to persist within host cells protects bacteria from the host immune system as well as from extracellular active antibiotics. Aiming to reduce relapse rates, we are investigating the underlying mechanism of bacterial persistence and aim to optimize current treatment strategies.

Biofilm: Pathogenesis, Diagnosis and Therapy
Many chronic infections are caused by the presence of a bacterial biofilm. A biofilm is an agglomerate of microorgansims, which can attach to biotic or abiotic surfaces and to each other, and are embedded in a matrix. The matrix enables the microorganisms to protect themselves from both the immune system and from the action of antibiotics. We are studying microorganisms sampled directly from biofilms by looking at their pathogenicity and behavior in various milieux, thereby searching for better diagnosis and treatment options for biofilm infections.