Microbial pathogenesis

Question 1

Which type of bacteria have Fimbriae - type 1 pili?

Answer 1

Gram negatives

Question 2

Which type of bacteria have CAPSULES?

Answer 2

Gram positives and gram negatives

Question 3

What are 3 nonspecific host defenses that fight bacteria

Answer 3

1. Physical barrier - deny access
2. Complement system - attack and break down cell walls
3. Phagocytes - remove debris and pathogens

Question 4

How do bacteria survive complement?

Answer 4

1. Surface proteins that inhibit or bind complement components
2. Capsules and biofilms mask activating substances

Question 5

How do bacteria survive phagocytosis?

Answer 5

1. capsules and biofilms
2. Exotoxins (leukocidins) - lyse WBCs
3. Intracellular survival

Question 6

Give examples of how bacteria survive intracellularly

Answer 6

1. Inhibit fusion of the lysosome to the phagosome
2. Escape into cytoplasm
3. resist lysosomal enzymes
4. inhibit oxidative pathway in once phagocytosed

Question 7

Strep Pyogenes characteristics in terms of creating an immune system divergence

Answer 7

Has super antigens!

Question 8

One of the mechanisms of evasion of proteolysis of and inactivation of secretory antibodies

Answer 8

expressin proteases

Question 9

How does Protein A prevent opsonization?

Answer 9

Binds to Fc portion of IgG - e.g. in Staph Aureus

Question 10

Group A strep pharyngitis can cause 2 automimmune conditions - ?

Answer 10

1. rheumatic fever

2. Glomerulonephritis

Question 11

LPS is considered what type of toxin

Answer 11

Endotoxin - part of the cell wall of gram negatives

Question 12

Strep Pyogenes - e.g. of Exotoxin

Answer 12

Streprokinase + Hyauronidase + Hemolysins

Question 13

Staph aureus exotoxins

Answer 13

Dnase + HYaluronidase + Leukocidins + Hemolysins

Question 14

Tetanus toxin properties

Answer 14

1. CNS effect
2. uses retrograde transport - to spinal cord
3. Inhibits release of inhibitory GABA - leads to constant contraction
4. Ongoing positive extensor and flexor response

Question 15

Tetanus causes - clinical manifestations

Answer 15

1. Risus Sardonicus

2. Opisthotonus

Question 16

Botulism toxin properties

Answer 16

1. PNS effect - Peripheral!!!
2. Exposure through contaminated foods
3. Carried to NMJunctions
4. OPPOSITE OF TETANUS - prevents PRESYNAPTIC release of Acetylcholine -
5. leads to Descending Paralysis and Respiratory Arrest
   - floppy baby syndrome

Question 17

Molecularly what does Botulinim Neurotoxin do?

Answer 17

Cleaves SNARE proteins - prevents vesicle attachment and release of Ach

Question 18

Consequences of low levels of Gram negative LPS

Answer 18

• results in fever and vasodilation

Question 19

Consequences of HiGH levels of Gram negative LPS

Answer 19

• alarming cytokine response
• SEPTIC SHOCK
  Intravascular Coagulation

Question 20

An example of an opportunistic pathogen

Answer 20

Coag negative Staph

Question 21

An example of a true pathogen

Answer 21

Shigella - 10 bacteria cause infection

Question 22

Which bacteria are part of the skin normal flora?

Answer 22

1. Staph (gram positive cocci)
2. Corynebact (Gram + bacilli)
3. Bacillus sp.. (Gram + bacilli)

Question 23

Which bacteria are part of the normal orpharynx bacteria?

Answer 23

ALL AEROBES - dental or head and neck abscesses

1. Streptococcus (gram positive aerobic cocci)
2. Nisseria (gram negative aerobic cocci)
3. Haemophilus ( (gram negative aerobic coccobacill))
4. candida

Question 24

Which bacteria are part of the normal intestinal flora

Answer 24

1. Enterococcus sp (UTI) (Gram + aerobic cocci)
2. Clostridium sp.
3. Candida sp.
4. Enteric bacilli, enterobacteriaceae (UTI)
   - E coli, klebsiella
5. Bacteroides (think abscess)

Question 25

Which bacteria are part of the normal vaginal flora

Answer 25

1. Viridans group strep
2. Peptostrep
3. Lactobacillus
4. candida

Question 26

Ecoli and Bacteroides synthesize which vitamin

Answer 26

K

Question 27

pneumonia epidemic

Answer 27

• respiratory viruses
  M. pneumoniae
  Legionella