Question

1.A capsule allows the bacteria to escape the host immune response by:

Killing specific T cells.

Activating the complement pathway.

Prevent phagocytosis.

Both a and c.

2.Fimbriae on Uropathogenic E. coli is considered which mechanism of penetrating host defenses?

Capsules.

Cell wall components.

Enzymes.

Antigenic variations.

3. Hyaluronidase secreted by Streptococci function by:

Clot formation.

Degrading collagen.

Degrading polysaccharide.

All of the above.

Answer 1

1. Prevent phagocytosis.

Capsules protect the bacterial cells by saving them from phagocytosis by WBC. The possible mechanism of this may be that capsules make bacterial surface components more slippery.

2. Antigenic variations.

Antigenic variations refers to the mechanism by which a bacteria alters its cellular surface structures with respect to the environment. This is done to survive in various environment or to avoid detection by the host's immune system, which is accomplished by random genetic rearrangements in pathogens.

3. Degrading polysaccharide

Clot formation is done by Coagulase enzyme in some bacteria and Collagenase in bacteria degrade collagen to facilitate spreading in host tissues. Hyaluronidase also help bacteria to spread through host tissues by degrading polysaccharides that hold animal cells together.