Question

.Name 6 pathogenic mechanisms (limit to 2 toxins) that help to promote a pathogen’s ability to produce disease and briefly how the mechanism works.  

Answer 1

Pathogenic mechanisms that help to promote a pathogen's ability to cause disease:

Pathogenic mechanism	Example of Pathogen	Mechanism of action
1. Adhesion	P. aeruginosa, E.coil, Neisseria species and V.cholera etc.	Expression of adhesins by certain pathogens help in their attachment to the cell surface of the mucosal tract and hence, help in shielding from host defences. Adherence helps in proliferation, host cell invasion, and activation of various host cell signalling cascades, contributing to the infection.
2. Biofilm formation	Staphylococcus aureus, Haemophilus influenza etc.	Biofilm formation helps the bacteria in attaching to the surface of the host cells and protect themselves from host defences including the antibiotic infection.
3. Lytic enzyme formation	Helicobacter pylori	H. pylori secretes urease that neutralizes the acidic lining of the stomach and causes the mucin layer to liquify, resulting in the invasion of the epithelial layer of the stomach.
4. Toxins eg- Diptheria toxin, A-B toxins etc.	P. aeruginosa, Corynebacterium diptheria etc.	These toxins are the enzymes that disrupt the host's signaling pathways and structural integrity of the cells to invade and cause infection.
5. Antibiotic resistance	MRSA (methicillin-resistant S. aureus) etc.	Due to the horizontal transfer between resistant bacteria and the susceptible one, antibiotic resistance spreads. This results in the ineffectiveness of any antibiotic used to counteract with the disease and hence, results in the vast-scale infection.
6. Capsule formation	Streptococcus pneumonia, Neisseria meningitidis, Pseudomonas aeruginosa etc.	This is a mechanism used by bacteria to evade clearence by the immune system cells. The capsular bacteria are protected from phagocytosis by not allowing opsonising antibodies to be recognized by macrophages and neutrophils.