Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2013

Shewanella algae an emerging pathogen: Insights form multiple comparative ‘omics’ analyses (#254)

Piklu Roy Chowdhury 1 2 , Jacqueline Melvold 1 , Hatch W Stokes 1 , Karl A Hassan 3 , Liam D Elbourne 3 , Aaron Darling 1 , Ian T Paulsen 3 , Steven P Djordjevic 1 , Ian G Charles 1
  1. The ithree institute, University of Technology Sydney, Sydney, NSW 2007, Australia
  2. New South Whales Department of Primary Industries, PMB 8, Cambden, NSW 2570, Australia
  3. Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, Australia
Shewanella algae is known for its ability to alter the ionization state of toxic chemicals and is therefore important in bioremediation, however it is also gradually emerging as a human pathogen. It is frequently isolated from different infection sites and is capable of causing a range of diseases from soft tissue infections to bacteremia. Members belonging to the genus Shewanella are genetically very diverse, which complicates molecular taxonomy but more importantly suggests the likelihood of lateral gene transfer (LGT) playing a major role in shaping the representative genomes. The role of LGT is perhaps not surprising, given the ability of S. algae to survive in diverse habitats including fresh and salt water, spoilt food, sewage and different parts of the human body. The ability to survive in a range of habitats also exposes S. algae to a wider gene pool, contributed by multiple organisms, further increasing the potential for LTG. Our group recently recovered a S. algae isolate, SA1, from Sydney on bacteriological growth media formulated for the selection of Vibrio cholerae. We characterized the genome of SA1, (the first S. algae genome to be sequenced) and carried out a comparative genomic analysis with other members of the genus Shewanella. This analysis revealed a myriad of ‘S. algae-specific’ genes encoding putative virulence factors. Proteomic analysis of SA1 lysates grown on LB-agar, horse blood-agar and TCSB-agar showed that many putative virulence factors were expressed only when SA1 was grown in the presence of bile salts or blood - suggesting that gene expression was regulated to suit a specific lifestyle choice. A detailed analysis of our proteomic and genomic data of SA1 suggests that this marine microorganism carries the requisite genetic repertoire important for an emerging pathogen.