Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2018

Guided missile strikes: Receptor targeting by a novel flagellatropic bacteriophage. (#148)

Rhys Dunstan 1 2 , Derek Pickard 2 , Josh Hardy 3 , Rhys Grinter 1 , David Goulding 2 , Claire Cormie 2 , Fasseli Coulibaly 3 , Gordon Dougan 2 , Trevor Lithgow 1
  1. Infection & Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton 3800, VIC, Australia
  2. Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, United Kingdom
  3. Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800 , Vic, Australia

Bacteriophages, or phages, are viruses that specifically infect bacteria. The interactions between phages and their bacterial hosts are widespread in nature and are often very complex - many of which influence the ability of a phage to replicate inside its bacterial host. Due to the increased interest in utilising phages as therapeutic tools to combat antibiotic resistant bacterial infections, it is necessary to gain a better understanding of their basic biology, specifically how they target and infect their bacterial hosts. We have isolated a novel bacteriophage, YSD1, capable of infecting a variety of different bacterial species.  The genome of YSD1 has been sequenced showing that it is most similar to the Chi sub-family of bacteriophages and its structure has also been solved using single-particle cryo-electron microscopy. Using a Salmonella Typhi host, we determined the infection kinetics of YSD1, discovering that it requires functional flagella for infection. Immuno-gold labelling of specific phage structural proteins revealed that YSD1_29 forms the tail fibres that target the bacterial flagella and that infection can be neutralised when YSD1 is pre-incubated with antibodies targeting these tail fibres. Finally, we show that a small subset of Salmonella strains expressing specific flagella serotypes are resistant to YSD1 suggesting that the exposed variable regions of the flagella surface are critical for phage recognition. This work provides a greater understanding of the interactions between a flagellatropic bacteriophage and its Salmonella host and could give insight into the targeting of other flagellated bacterial species by their respective phages.