Virulence

Question 1

Microbiome

Answer 1

Applied to an entire community of microbes, but can also refer to the DNA associated to a community. Many are mutaulistic with the host and some are opportunistic. There more bacterial cells than mammalian in humans. There are over 10 thousand microbe species in humans. Endogenous microbes are part of the normal flora. Exogenous microbes are not normally part of the flora.

Question 2

Carrying Staphyloccocus

Answer 2

This gram positive microbe has been carried by most people at some point. They are Endogenous, meaning they do not need to be transmitted.

Question 3

Opportunistic pathogen

Answer 3

An organism that causes infection when the oppportunity (change in natural immunity) arises. Usually does not pose a threat. Can threaten an immunocomprimised individual.

Question 4

Virulence

Answer 4

The capacity of an organism to cause damage to a host. LD50 is the lethal dose of the organism needed per ml to kill 50% of hosts. ID50 is the infection dose of the organism needed to infect 50% of hosts.

Staph aureus is hard to measure virulence due to only being suited to infecting humans.

Question 5

Virulence Factors

Answer 5

Component of a microbe that contribute to disease mechanism. Do not all exist in all models and are not essential for survival

Adhesin - Allows binding to host tissue.

Invasin - allows entry into cells or tissue. They can break down adhesin junctions to enter tissue.

Impedim - Allows the pathogen to avoid host immunity.

Aggressin - Causes damage to the host, challenging immunity. For example, destroying immune cells.

Modulin - Induces damage indirectly, altering immune response.

Question 6

Gram negative pathogens

Answer 6

Escherichia, Klebsellia, Enerobacter, Pseudomonas, Bacteriodes, Salmonella, Shigella, Haemophilus

Question 7

Gram positive pathogens

Answer 7

Staphylococcus, Streptococcus, Enterococcus,
Clostridiodes (clostridium)