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Flashcards in Test q's Deck (132)
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1

How does meningococci enter the blood?

from the pharynx- via pilus-mediated adherence to and penetration of the mucosal epithelium

2

What is n meningitidis' virulence factor?

- sex pilus
- produces an IgA protease that facilitates survival by destroying antibodies

3

sputum gram stain shows many neutrophils but few or no organisms

Legionella pneumonia

4

very high fever in a smoker with diarrhea, confusion, and cough

Legionella pneumonia

5

Why cant legionella gram stain?

bc they have unique lipopolysaccharide chains on the outer membrane that inhibit gram staining

6

What is staph aureus' virulence factor that is bound to the peptidoglycan wall?

Protein A: binds to the Fc portion of IgG at the complement binding site thus preventing activation of complement
= decreased opsonization

7

What substance is SECRETED by staph?

Hemolysin: can produce hemolysis and destruction of neutrophils, macs, and platelets

8

Which bacteria have the ability to take up free DNA from the environment (transformation)

Strep pneumo
H influ
Neisseria meningitidis

9

What bacteria are responsible for secondary bacterial pneumonia?

1. Strep pneumo
2. Staph aureus
3. H influenzae

10

What organism has a lipooligosaccharide

N meningitidis

11

What is significant about N meningitidis' LOS?

1. It correlates with the outcome of the disease
2. It causes sepsis by induction of inflammatory response (interacts with toll like receptor 4)
3. Cause of cutaneous petechiae and hemorrhagic bullae
4. Causes Waterhouse-Friderichsen syndrome

12

What is the major virulence factor of Group A strep?

Protein M: inhibits phagocytosis and inactivates complement

13

Streptolysin O MOA?

- found on group A strep- strep pyogenes
- lyses erythrocytes and PMNs but does not convey resistance to phagocytosis

14

budding yeast with a thick capsule

Cryptococcus

15

What does the DPT vaccine target?

the binding component (B subunit) of Diptheria's exotoxin
- antibody binding prevents the exotoxin from attaching to host cell membrane and preventing disease

16

In a pt with bronchial asthma and CBC with eosinophilia, what do you suspect?

- Aspergillus
- Allergic Bronchopulmonary Aspergillus
- seen in steroid dependent asthmatics

17

How does typhoid fever cause death?

- causes inflammation within Peyer's patches leading to intestinal hemorrhage and gut perforation
- polymicrobial peritonitis and sepsis

18

Pt presents with abdominal cramping, low fever, constipation and salmon colored rose spots on the abdomen, plus hepatosplenomegaly

Salmonella typhi

19

What do the different HIV structural genes encode:
1. Gag
2. Pol
3. Env

1. Gag = nucleocapsid proteins p24 & p7
2. Pol = reverse transciptase
3. Env = envelope glycoproteins ie gp120 and gp41

20

What is the only gram + bug with an endotoxin?

Listeria

21

Stain with carbolfuschin = what bugs?

Acid fast stain = Ziehl neelsen: Nocardia and Mycobacteria

22

Giemsa stain?

1. Chlamydia
2. Borrelia
3. Rickettsia
4. Trypanosomes
5. Plasmodium

23

mucicarmine = ?

Cryptococus, stains the thick polysaccharid capsule red

24

Catalase positive organisms?

PLACESS:
pseudomonas
listeria
aspergillus
candida
e coli
s aureus
serratia

25

What are the conjugated vaccines and why are they conjugated?

for capsular antigens- a protein is conjugated to the polysaccharide antigen to promote T cell activation and subsequent class switching- a polysaccharide antigen alone cannot be presented to T cells (only IgM would be produced)
ex) H influenza type B and Meningococcal

26

What are the urease positive bugs?

1. Cryptococcus
2. H pylori
3. Proteus
4. Ureaplasma
5. Nocardia
6. Klebsiella
7. Staph epidermidis
8. Staph saprophyticus

27

Protein A: who has it and what does it do?

Staph aureus
- Binds to Fc portion of Ig, prevents opsonization and phagocytosis

28

IgA protease: who has it and what does it do?

- enzyme that cleaves IgA in hinge region, secreted by SHiN: s pneumo, h influ, neisseria
- used to colonize resp mucosa

29

M protein: who has it and what does it d?

- Group A strep
- prevents phagocytosis

30

How do ST and SLT from shigella and EHEC cause HUS?

their exotoxins: binding to 60S ribosome and enhances cytokine release