NEWS Listeria bacterium found in food, which can infect people and cause temporary gastro-intestinal distress, is a serious health risk for pregnant women and for people with compromised immune systems. According to a dissertation from Umeå University, the bacterium, which sometimes causes the lethal illness listeriosis, reacts to light by activating defence mechanisms.
Listeria monocytogenes, named after the British surgeon Joseph Lister, is ubiquitous in nature but can sometimes spread to food, especially to unpasteurised dairy products and charcuterie. The Listeria bacterium can grow in food stored in the fridge, and if contaminated food is consumed without being properly heated, the bacterium can cause infection.
Researchers have now discovered a new property in Listeria; namely that the bacterium activates protective mechanisms when exposed to light. This discovery can, in future, be used by the food industry to prevent the spread of Listeria.
In the dissertation, doctoral student Christopher Andersson also describes the discovery of two new molecules that combat the pathogenicity of the Listeria bacterium. The researchers also studied how the molecules can be used to prevent the bacterium from causing disease.
For healthy individuals, the Listeria bacterium usually causes no extreme harm apart from a few days of stomach problems. For individuals with a compromised immune system or for pregnant women, however, the bacterium can be very dangerous. If a bacterial infection spreads to the brain it can progress to “listeriosis”, which has a mortality rate of 20–30 percent. If a pregnant woman is infected, the bacteria can spread to the foetus and cause miscarriage.
“Hopefully, this new knowledge on how light and these small molecules affect the bacterium can, in future, be used to prevent the spread of Listeria and help treat listeriosis,” says Christopher Andersson, doctoral student at the Department of Molecular Biology at Umeå University and author of the dissertation.
Read a digital publication of the dissertation
On Thursday 4 February, Christopher Andersson, Department of Molecular Biology at Umeå University, defends his dissertation entitled: Regulatory pathways and virulence inhibition in Listeria monocytogenes. Opponent: Professor Claude Parsot, Unite de Pathogenie Microbienne Moleculaire, Institute Pasteur, Paris. Head supervisor: Professor Jörgen Johansson, Department of Molecular Biology at Umeå University.
The public defence of the dissertation takes place at 09:00 in the auditorium (Stora hörsalen), KB3B1, main entrance, floor 1, in the KBC Building at Umeå University.
Christopher Andersson, Department of Molecular BiologyPhone: +46 90-785 6739
Email: christopher.andersson@umu.se
Bild: Scanning electron micrograph of Listeria monocytogenes (Wikipedia).
Editor: Anna Lawrence