Meet the Scientists: Dr. Kathryn Holt

We began our research into the dysentery-causing bacteria Shigella with local expert Kat Holt.

The Holt group at the University of Melbourne are the next generation of microbiologists – a laboratory full of computer nerds, who sequence whole genomes of different disease-causing bacteria. But unlike traditional genome-sequencing approaches, their approach is to sequence and compare whole populations of clinical isolates from different locations, focusing on differences in the genetic differences in their transmission, antibiotic resistance, detection and more.

In our meeting, Kat told us about how so few Shigella can cause an infection and the important role of nutrition in preventing Shigella from infecting and causing dysentery. She also described the Shigella invasion plasmid (a plasmid is a mobile set of genes in circular form, separate from the genome), and the role this massive set of genes play in gaining entry through our defenses and into our intestinal epithelium (the cells lining our gut), and how they take advantage of our immune system to spread throughout our large intestine in a dysentery infection.

Kat also told us about her amazing work in discovering the changing infections of different Shigella species (such as Shigella sonnei) around Earth over the last century and implications this has for the millions of people still infected by Shigella each year and the role that clean water supplies can have in preventing dysentery.

Kat also rightly emphasised that the endogenous (native) human intestinal biota (particularly our resident bacteria) would play a large role in trying to fight off any Shigella bacteria in our gut…something we will surely work into our story!