Question

1. Name 2 colonization factors that allow N. meingitidis the ability to colonize the nasopharynx.
2. What mechanisms do Staphlococcus aureus possess that help with resistance to the host immune system?

Answer 1

The 2 colonization factors that allow N.meningitidis the ability to colonizw the nasopharynx are :

1. The bacteria expresses a number of surface and secreted proteins such as adhesins( e.g pili mostly bacterial type IV pili (Tfp) and opacity proteins)t hat bind to molecules in the nasopharynx. Some other proteins are lactoferrin- and transferrin-binding proteins that anable the bacteria to acquire iron which is a a crucial growth factor required during the process of colonization and disease.
2. The bacteria expresses two distinct porins i.e PorA and PorB both of which are β-barrel proteins,which associate into trimers in the bacterial outer membrane so that there can occur diffusion of small hydrophilic nutrients diffuse into the cell.

The mechanisms that Staphlococcus aureus possess that help with resistance to the host immune system are as follows:

• The bacteria secretes different immune evasion molecules such as proteases that function to cleave the components of the host innate immune system, thereby disrupting the integrity of extracellular matrix and intercellular connections of different tissues.
• The bacteria also secretes proteins that function in the activation of the host zymogens that go on to target specific defense components of the host itself.
• Some secreted proteins inhibit the anti-bacterial function of immune cells such as neutrophils or complement system proteases thus increasing the chances of survival of Sa.aureus in the host.