Sunday, 9 September 2018

Why sepsis from a staph infection causes organ failure


For patients diagnosed with a Staphylococcus aureus infection, often referred to as a staph or MRSA infection, every minute counts. The bacteria create havoc in the body. The immune system goes into overdrive. The heightened immune response can lead to sepsis, which kills 30 to 50 per cent of the people who develop it. In Canada, sepsis is the 12th leading cause of death.

Scientists have known for some time that one of the reasons a staph infection is so deadly is that the bacteria send out a toxin, known as Alpha Toxin (AT), which quickly worsens sepsis. University of Calgary scientists at the Cumming School of Medicine's (CSM) Snyder Institute for Chronic Diseases have discovered the most important target of the toxin and how to neutralize the danger.
Using a process that allows scientists to see what's happening inside living animals, called intravital microscopy, researchers discovered that the toxin causes platelets to respond abnormally in mice. Platelets' primary role is to help stop bleeding in mammals after injury. What's relatively unknown is that platelets also play a role in the body's defenses against bacteria. Normally, platelets coat bacteria to prevent the spread of a microbe throughout the patient. However, during sepsis caused by staph infection, as the amount of toxin in the bloodstream increases, the platelets aggregate to form clumps. Those clumps deposit in the liver and kidneys, causing serious damage and eventually organ failure.

See:

Bas G.J. Surewaard, Ajitha Thanabalasuriar, Zhutian Zheng, Christine Tkaczyk, Taylor S. Cohen, Bart W. Bardoel, Selina K. Jorch, Carsten Deppermann, Juliane Bubeck Wardenburg, Rachelle P. Davis, Craig N. Jenne, Kendall C. Stover, Bret R. Sellman, Paul Kubes. α-Toxin Induces Platelet Aggregation and Liver Injury during Staphylococcus aureus Sepsis. Cell Host & Microbe, 2018; DOI: 10.1016/j.chom.2018.06.017

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

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