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 CF and Pseudomona  



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Author8 Posts
  #1

What is the mechanism of action by which Pseudomona affects pts w/Cystic Fibrosis?

Sorry guys, don't have an exact answer on this. Please give ur opionions. Will appreciate them!




  #2

pseudomonas aeruginosa colonizes and infects immunocompromized pts .
it cant infect healthy people coz has weak invasive ability.
in immunocompromized pts , it releases various toxins like exotoxin A which inhibits protein synthesis.
In CF pts it colonizes lungs and causes chronic pneumonia which progressively destroys lungs


  #3

Hmm, how about the slimy capsule mash? I was thinking probably the slimy capsule has something to do with it. Maybe b/c the extra mucous creates a perfect environment for the slimy pseudomona. :?

By the way, u're right. Pseudomona inhibits protein synthesis by blocking EF2; same mechanism as diptheria.


  #4

yeah u r right dat slimy capsule is antiphagocytic and helps in adhesion..


  #5

not to mention the trend of increasing antibiotic resistance & that trying to treat it with a cephalosporin probably means the pt ends up getting c diff...


  #6

Apparently, P. aeruginosa binds more effectively to mucin from people with CF.


  #7

I just think in CF patients the decreased clearance of mucus from the respiratory airways creates a more friendly environnement to P.aeruginosa allowing them to multiply and making it harder for defense mechanisms to reach the bacteria e do an effective job. Resistance to antibiotics does not make a bacteria more able to cause a disease, just makes it harder to cure the disease. The mucus of CF patients is completely like that of normal people just more concentrated, so that does not imply greater affinity for the mucin. CF patients aren't immunocompromised and all other virulence factors are the same because is the same agent we're talking about. Pseudomonas affects the CF patients using the same way it would affect anybody, just more easily.


  #8

Well, decreased mucociliary clearance is definitely an important factor.

www.ncbi.nlm.nih.gov/entrez...bstract&list_uids=11121762

This article cites enhanced binding to epithelial cells (and mucin - though this latter one seems a bit more controversial); the mucin is more highly sulfated and has a higher sialic acid content in CF patients.





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