Week 2

Question 1

Define bacterial transformation.

Answer 1

When bacteria take up free floating DNA.

Question 2

Define transduction.

Answer 2

When bacteria get new DNA from a bacteriophage.

Question 3

Define conjugation

Answer 3

When two bacteria hook up to share genetic material.

Question 4

What are axial filaments and what do they do?

Answer 4

Flagella located between the outer and inner membranes of spirochete bacteria that help them move in a snake-like fashion.

Question 5

Are slime-layers covalently attached to bacteria? What about capsules?

Answer 5

Slime layers - no

Capsules - yes

Question 6

What is an endospore?

Answer 6

When gram-positive (only happens with gram +) bacteria go into a dormant state that is resistant to harsh environments.

Question 7

What is the difference between an exotoxin and an endotoxin?

Answer 7

Exotoxins are secreted by live bacteria, endotoxins are released when bacteria die.

Question 8

What do techoic acids and lipotechoic acids do to neutrophils?

Answer 8

They activate neutrophils!

Question 9

Name two ways to differentiate staph from strep.

Answer 9

1. Strep grows in chains (strep ladder), staph grows in clusters.
2. Strep is catalase negative, staph is catalase positive!

Question 10

Is LPS found on gram-negative, or gram-positive bacteria?

Answer 10

Gram-negative!

Question 11

Is LPS an endotoxin?

Answer 11

Yeah

Question 12

Do gram-positive bacteria have a periplasmic space? What is found in the periplasmic space?

Answer 12

No, only gram-negative bacteria have a periplasmic space (space between the inner and outer membranes).

Enzymes are found in the periplasmic space - antibiotics can be degraded here.

Question 13

What is O antigen?

Answer 13

same thing as LPS

Question 14

Which one does not cause tissue damage?

a) ETEC
b) EPEC
c) EAEC
d) EHEC
e) Shigella

Answer 14

a) ETEC

Question 15

Name an arachidonic acid-derived molecule that causes vasodilation.

Answer 15

Prostacyclin - PGI2

Question 16

Name the arachidonic acid-derived molecules that causes vasoconstriction.

Answer 16

Thromboxane A2 (TXA2), LTC4, LTE4, LTD4

Question 17

Name the arachidonic acid-derived molecules that cause increased vascular permeability.

Answer 17

PGD2, PGE2, PGI2, LTC4, LTD4, LTE4

Question 18

Name an arachidonic acid-derived molecule that promotes neutrophil chemotaxis.

Answer 18

Leukotriene B4 - LTB4

Question 19

Name the arachidonic acid-derived molecules that inhibit chemotaxis.

Answer 19

Lipoxin A4 (LXA4) and Lipoxin B4 (LXB4)

Question 20

Describe an uncomplicated case of a UTI.

Answer 20

Non-pregnant female w/ no risk factors - outpatient setting.

Question 21

Should you treat asymptomatic bacteruria?

Answer 21

Only if the patient is pregnant or is about to have a urologic procedure performed with a high risk of bleeding.

Question 22

How does one diagnose C. diff colitis?

Answer 22

PCR for toxin in stool or colonoscopy

Question 23

Name the antibiotics used to treat non-severe as well as severe cases of C. diff colitis.

Answer 23

For non-severe disease: oral vancomycin or oral metronidazole.

For severe disease: oral vancomycin

Poo pills for recurrent, refractory cases

Question 24

Which bugs are associated with atypical pneumonia?

Answer 24

1. Mycoplasma pneumonia
2. Legionella pneumophilia
3. Chlamydophilia pneumoniae

Question 25

Which bugs are associated with typical pneumonia?

Answer 25

1. Strep. pneumoniae | 2. Haemophilus influenzae

Question 26

Which bugs cause bloody diarrhea?

Answer 26

1. Shigella 2. EHEC 3. Campylobacter 4. Non-typhi salmonella 5. Yersinia

Question 27

Which bugs cause watery diarrhea?

Answer 27

1. Vibrio cholerae 2. EPEC 3. ETEC

Question 28

Which bugs cause meningitis in neonates?

Answer 28

1. Streptococcus agalactiae 2. Listeria monocytogenes 3. E. coli

Question 29

Which bugs cause meningitis in young adults?

Answer 29

1. Streptococcus pneumoniae | 2. Nisseiria meningitidis

Question 30

Which bugs cause meningitis in children?

Answer 30

1. Streptococcus pneumoniae 2. Haemophilus influenzae type B 3. Neisseria meningitidis

Question 31

Which bugs cause meningitis in older adults (over 50)?

Answer 31

1. Streptococcus pneumoniae 2. Listeria monocytogenes 3. Neisseria meningitidis

Question 32

Describe the pathogenesis of salmonella enteriditis.

Answer 32

1. It is ingested and goes to the terminal ileum and colon. 2. T3SS injects toxin into M cells, M cells endocytose the bacteria. 3. M cells poop out the bacteria and macrophages take it up. 4. Bacterial replication happens in macrophages and are released. 5. Bacteria enter GI epithelial cells, staying in vacuoles to hide from the immune system. 6. When bacterial LPS leaks into cytosol of GI cells --> immune response, cell death, bloody diarrhea.

Question 33

Name the first line treatments for uncomplicated UTI.

Answer 33

1. Nitrofurantoin 2. Trimethoprim-sulfamethoxazole 3. Fosfomycin -uncomplicated outpatient pyelonephritis: fluoroquinolone

Question 34

Which drugs would you use to treat nosocomial pseudomonas pneumonia?

Answer 34

1. Cephalosporins 2. Piperacillin 3. Carbapenems

Question 35

Which bugs can cause uncomplicated UTI?

Answer 35

1. E. coli 2. Klebsiella 3. Proteus mirabilis 4. Staph saprophyticus

Question 36

Elderly men, endocarditis, colon cancer.

Answer 36

Strep. bovis

Question 37

What is CagA?

Answer 37

Virulence factor of some strains of H. pylori that is associated with more severe symptoms - ulcers and cancer. It is injected by bacteria into GI cells via a T3SS and it inhibits apoptosis and promotes growth --> cancer.

Question 38

What are the two most common causes of ventilator-associated pneumonia?

Answer 38

1. Staph aureus | 2. Pseudomonas