Should you care what your favourite pathogen likes to eat? – Insights into the role of metabolism for virulence of Haemophilus influenzae strains

TITLE:  Should you care what your favourite pathogen likes to eat? – Insights into the role of metabolism for virulence of Haemophilus influenzae strains   

SPEAKER:  Prof. Ulrike Kappler

ABSTRACT: Respiratory tract infections with Haemophilus influenzae are extremely common in patients suffering from chronic lung diseases, and are characterized by high rates of recurrence and persistence. While the role of surface proteins and virulence factors such as biofilms in host-pathogen interactions are well understood, the high genetic variability between strains has so far prevented the identification of suitable vaccine candidates for non-typeable, unencapsulated strains of H. influenzae. In contrast, how energy-generating metabolic processes contribute to virulence and persistence of H. influenzae in the host, is comparatively unexplored. However, these processes are essential for bacterial survival and growth, and are even more critical for bacteria that, like H. influenzae, have only a single known natural niche. This presentation will explore the adaptation of H. influenzae metabolism to survival in the human respiratory tract, the role of niche-specific growth substrates for virulence, and why generating energy by ‘respiration-assisted fermentation’ can enhance survival in the host. Lastly, we will look at how H. influenzae metabolism shapes its environmental niche, the human respiratory epithelia, using immunomodulatory molecules that reduce the immune response to H. influenzae infections.

BIOGRAPHY: I am a professor in microbiology and biochemistry at The University of Queensland (UQ) and my time is equally divided between research and teaching. My research interests are in bacterial metabolism and physiology, and understanding how specific enzymes and metabolic pathways underpin survival of bacteria in diverse environments. A significant part of my work centres on bacterial sulfur metabolism, where my lab has investigated mechanisms of energy generation, detoxification of reactive sulfur species and repair of damage to sulfur-containing biomolecules. After extensive work in this area using extremophiles as well as soil and marine bacteria, we started to investigate the role of sulfoxide reduction for virulence in bacterial pathogens, and this has now developed into an extensive program of research on the physiology and pathogenesis of the human respiratory pathogen Haemophilus influenzae. Current focus areas are the role of H. influenzae metabolism for host-pathogen interactions, as well as molecular defences against antimicrobials produced by the human immune system, where sulfoxide formation on sulfur-containing biomolecules is a common type of damage.