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Visualising How Salmonella Genes Are Regulated

27th September, 2016

In a collaboration with scientists at the University of Liverpool, Dr Aoife Colgan and Assistant Professor Carsten Kröger (both of the Department of Microbiology, Trinity College Dublin) have determined the roles of the important regulatory systems that allow the human pathogen Salmonella Typhimurium to cause disease.

We know that bacterial pathogens kill millions of people each year, and that bacteria carry “virulence” genes that allow them to cause disease. During infection of humans with Salmonella, the switching on and off of these virulence genes is carefully regulated to ensure expression at the “right time and right place”, but how is this process controlled?

Scientists based at the University of Liverpool and Trinity College Dublin have determined the roles of the important regulatory systems that allow the human pathogen Salmonella Typhimurium to cause disease. The team led by Professor Jay Hinton used the latest RNA-seq technology to study mutant bacteria that are unable to regulate key virulence processes, and defined the regulatory proteins that control expression of Salmonella coding genes and small RNAs during infection.

The lead author of the study, Dr. Aoife Colgan said “by using mutants of a single Salmonella strain that lack 18 different regulatory systems, we have generated a unique set of data. I am excited that the results are now available to all researchers at SalComRegulon, that my work can now be used to gain new insight into the process of Salmonella infection, and perhaps inspire new therapies”.

Professor Hinton said that he hoped that the data would contribute to our understanding of Salmonella-induced gastroenteritis, and to the lab’s current research on a lethal disease in Africa called invasive non-typhoidal Salmonellosis. The study is published in the open-access PLoS Genetics journal, and can be accessed here.

Salmonella facts:
• Worldwide, Salmonella kills more than 1 million people each year.
• Symptoms of salmonellosis (food poisoning caused by Salmonella) are fever, headache, abdominal pain, diarrhoea, nausea and vomiting, and are usually self-limiting after a week. In some cases, particularly in the young and very elderly, dehydration can become severe and life threatening.
• Salmonella Typhimurium is found in a broad range of animals, birds and reptiles, as well as the environment. Take care during the barbecue season - the bacterium causes food poisoning in humans mainly through the consumption of raw or undercooked contaminated food of animal origin - including poultry, eggs, meat, and milk, and also salad vegetables.


The Salmonella Typhimurium 4/74 microprocessor. This cartoon highlights the interconnection of regulatory systems and important gene switches that integrate various environmental stimuli. Illustration by Liza Wolfson. Courtesy of Jay Hinton.