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Bacterial virulence factors

The question:
د. رمزي كان فيه سؤال فى امتحان النهارده

mcq: how bacteria invades the tissue
a-exotoxin

b- hyaluronidase
don't remember the rest choices

plz explain the answer thnx.
 
The answer:
بص يا استاذ

اجابة السؤال ده هاتلاقيها في موضوع ده تحت عنوان:
Bacterial virulence factors




A. the ability to adhere to host cells and resist physical removal: By
1. Pili (Fimbria).
2. Adhesins.
3. Capsules.
B. Invasion:
It is the ability of the microorganism to enter host's tissues, multiply there and spread to other tissues
It is one of the main mechanisms by which bacteria can cause disease
This invasion is helped by

1. Invasins:
Some bacteria produce invasins that activate host epithelial cells to phagocytose the bacterial cells.
E.g.: invasins of Shigella, enteroinvasive E. coli and Strept. pneumoniae.
This helps to protect bacteria from other body defenses e.g.: antibodies and complement.

2. Enzymes:
These are produced by many species of bacteria and play an important role in the infectious process, for example:
  • Collagenase and hyaluronidase which break down collagen and hyaluronic acid allowing the bacteria to spread through the tissues, e.g. Strept. pyogenes.
  • Lecithinase which is toxic enzyme that breaks down lecithin of cell membrane, e.g. Clostridium perfringens.

C. the ability to compete for iron and other nutrients.


D. the ability to resist host immune defense.


E. Damage to the host cells by inflammatory response or bacterial toxin.

يبقي زي ماهوا واضح من الكلام اللي فات
ان البكتريا بتعمل غزو للجسم "بتدخل الجسم" باكتر من طريقة
منها انها تطلع انزيمات تقوم بتكسيير الخلايا ومحتوياتها وما يحيط بها لسهيل عملية الدخول



2 التعليقات:

غير معرف يقول...

طب ليه يا دكتور مش exotoin مش هو برضه بيعمل pores in cell membrane؟

Dr. Ramzy يقول...

The answer present here:
http://bacteriastories.blogspot.com/2009/12/exotoxins.html

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