Microbial Pathogenicity-32

Question 1

Important microbial pathogens examples are

3

Answer 1

Virus- H1N1 influenza virus, ss RNA, enveloped

Fungi- Trichophyton spp

Prions- Kuru

Question 2

Important microbial pathogens examples are

3

Answer 2

Helminths- Anclyostoma duodenale Hook worm

Protozoa- Plasmodium spp Malaria parasites

Bacteria- Bacillus Anthracis (Gram positive endospore forming rod shaped bacterium).

Question 3

Gram positive bacteria have

Answer 3

thick cells walls and consists of peptidoglycan which traps and retains crystal violet stain.

Question 4

Gram negative bacteria have

Answer 4

cell walls with 2 layers, a thin peptidoglycan layer and thick outer membrane which contains polysaccharides bonded to lipids.

Question 5

Koch’s postulates are

Answer 5

outlines/Guidelines to demonstrate a specific pathogen cause specific disease symptoms

Question 6

Koch’s Postulates outline

4 steps

Answer 6

1. ) Pathogen is present in individual with disease
2. ) Sample of microorganism from disease host can grow in pure culture
3. ) Sample of pure culture cause same disease when injected into healthy host.
4. ) Microorganism is recovered from infected host

Question 7

Key stages of Microbial Pathogenesis are

4

Answer 7

Adherence to host cells (Skin or Mucosa),
Invasion of host tissues (Epithelium),
Replication within host tissues (Colonize and growth production of virulence factors),
Disease causing damage to host tissues (pathology)

Question 8

Adherence to host cells

Answer 8

Skin or Mucosa

Question 9

Invasion of host tissues

Answer 9

Epithelium

Question 10

Replication within host tissues

Answer 10

Colonize and growth production of virulence factors

Question 11

Disease causing damage to host tissues

Answer 11

pathology

Question 12

List the broad classes of bacterial virulence factors and provide examples for each

Adherance to host cells

Answer 12

Adhesions such as Fimbriae-Attachment pilus bind to host cells eg Neisseria Gonorrhoeae.

Question 13

List the broad classes of bacterial virulence factors and provide examples for each

Invasion of host tissues

Answer 13

Motility factors,
Flagella move through mucus eg Helicobacter pylori.

Internalin-related proteins (InlB) eg Listeria monocytogenes

Question 14

List the broad classes of bacterial virulence factors and provide examples for each

Replication within host tissues

Answer 14

Siderophores (bind iron) Yersinia pestis eg siderophore yersiniabactin solubilizes metal bound to host proteins and transports back to bacteria.

Capsules (resist phagocytosis) eg Streptococcus pneumoniae.

Question 15

List the broad classes of bacterial virulence factors and provide examples for each

Disease causing damage to host tissues (pathology)

Answer 15

Toxic virulence factors. Endotoxins cause inflammation Exotoxins can be fatal.

Question 16

Exotoxins are..

3 types

Answer 16

produced in living bacteria and released into surrounding medium.

Cytotoxins
Neurotoxins
Enterotoxins

Question 17

Cytotoxins

Answer 17

Streptolysin made by bacteria Streptococcus pyrogenes cause complete lysis of RBC (Beta Hemolysis).

Question 18

Neurotoxins

Answer 18

Botulinum made by bacteria Clostridium botulinum, cause paralysis

Question 19

Enterotoxins

Answer 19

shiga toxin made by bacteria shigella dysenteriae cause severe dysentery.

Question 20

Endotoxins are

Answer 20

lipopolysaccharides (LPS) in outer membrane of Gram negative Bacteria and elicit strong immune responses.
Eg Neisseria Gonorrhoeae cause inflamation

Question 21

Effects of Endotoxin lipid A are

Answer 21

Fever, Blood clotting, Inflammation and Shock