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Role of NADase activity in necrotizing soft tissue infection

Gessa, Arianna (2021) MOBM02 20211
Degree Projects in Molecular Biology
Popular Abstract
The flesh-eating bacterium and inflammation run amok

Streptococcus pyogenes is a bacterium that can infect humans and cause a wide range of symptoms, from the common strep throat to life-threatening infections. In rare cases, when this bacterium pushes its way down into our deeper skin layers, like in necrotizing skin and soft-tissue infection (NSTI), the destruction of the local tissue sometimes becomes so bad that whole limbs have to be amputated to stop the spread of disease. The reason that S. pyogenes is sometimes referred to as as a “flesh-eating” bacterium, is that the infection gnaws away at our tissue. Interestingly, our very own immune cells – called on to clear to the infection – contributes to such tissue degradation!... (More)
The flesh-eating bacterium and inflammation run amok

Streptococcus pyogenes is a bacterium that can infect humans and cause a wide range of symptoms, from the common strep throat to life-threatening infections. In rare cases, when this bacterium pushes its way down into our deeper skin layers, like in necrotizing skin and soft-tissue infection (NSTI), the destruction of the local tissue sometimes becomes so bad that whole limbs have to be amputated to stop the spread of disease. The reason that S. pyogenes is sometimes referred to as as a “flesh-eating” bacterium, is that the infection gnaws away at our tissue. Interestingly, our very own immune cells – called on to clear to the infection – contributes to such tissue degradation! Indeed, the bacterium produces an arsenal of proteins, called virulence factors, that work as drugs on our immune cells and make them go bonkers. The hyped-up immune cells can then cause an exaggerated inflammatory response, which unfortunately may end up killing the very human that these cells intended to protect.

To study this kind of infection in humans, the world’s largest NSTI patient cohort study, called INFECT, took place between 2013-2017. In our studies we have evaluated, for 53 of these NSTI patient bacterial isolates, if the activity of one important virulence factor called the NAD+ glycohydrolase (NADase), may impact on the outcome of disease.

Strikingly we found that all of the S. pyogenes NSTI isolates produces an active NADase and that the higher the activity of this bacterial virulence factor was, the more likely it was that the patient ended up with a life-threatening inflammatory response called sepsis.



Master’s Degree Project in Molecular Microbiology/ 30 C Department of Biology, Lund University

Supervisor: Fredric Carlsson Co-supervisor: Elin Movert
Microbiology Group/Department of Biology (Less)
Please use this url to cite or link to this publication:
author
Gessa, Arianna
supervisor
organization
course
MOBM02 20211
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9060865
date added to LUP
2021-07-05 11:08:19
date last changed
2021-07-05 11:08:19
@misc{9060865,
  author       = {{Gessa, Arianna}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Role of NADase activity in necrotizing soft tissue infection}},
  year         = {{2021}},
}