Bacterial Polysaccharide Research

Bacterial Polysaccharides Research group at QUT is led by Dr Johanna Kenyon

What we do:

Our work focuses on important sugary structures on the bacterial cell surface, known as capsular polysaccharides (CPS) and lipooligosaccharides (LOS). These structures provide a protective barrier surrounding the cell, shielding bacteria from the host immune response and external assaults in harsh environments. Capsular polysaccharides are also primary targets for promising therapeutic strategies (e.g. bacteriophage and immunotherapies) for treating otherwise untreatable multidrug-resistant infections.

The overall aim of our research is to increase fundamental understandings on the genetics that drive CPS and LOS synthesis in Gram-negative bacteria, with a particular focus on the WHO critical priority bacterial pathogen, Acinetobacter baumannii. Our goal is to translate these new understandings into useable information for researchers, clinicians, and public health laboratories to ultimately improve approaches to clinical surveillance and targeted design of non-antibiotic therapeutics.

Understanding polysaccharide evolution

One of our primary research focuses is generating new knowledge on how genes affect the structure of polysaccharides on the bacterial cell surface, and how genetic differences correlate with bacterial survival in hostile environments. We use comparative genomics, modern mutagenesis technologies, imaging techniques and phenotypic assays to study polysaccharide heterogeneity and evolution in A. baumannii. We further collaborate with researchers at the University of Sydney, Australia, and the Russian Academy of Sciences, Moscow, Russia, to combine genome sequencing data with structural chemistry to better understand the complex pathways leading to polysaccharide biosynthesis.

Transmission electron microscopy image of A. baumannii cell. Image courtesy of Johanna Kenyon (QUT, Australia).

Leading the international database for CPS and LOS gene typing in A. baumannii

Closely related bacterial isolates can produce different forms of CPS and/or LOS structures, and the type can be predicted using whole genome sequence data. The type of CPS produced can influence pathogenicity and is an important determinant for lytic bacteriophage and monoclonal antibodies that are currently being explored as new therapeutics.

Our team developed and continues to maintain the international databases for A. baumannii CPS and LOS typing. Researchers, clinicians, public health professionals, and hospital infection control units seeking to type A. baumannii strains are welcome to access the database at Kaptive , Kaptive-Web  and PathogenWatch . Users seeking inclusion of their sequences in the typing schemes are directed to the submission portal  or can contact Dr Kenyon’s team for assistance.

Developing an open-access biobank

The Bacterial Polysaccharides Research team is currently establishing a strain bank that will hold A. baumannii strains representative of each CPS and LOS type. Researchers wanting to examine specific strains, test pharmaceutical targets, or evaluate potential phage therapies can contact Dr Kenyon.

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