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Flashcards in Micro 2 Deck (21):
1

Haemophilus influenza morphology, transmission, growth

--gram (-) coccoid rods
--aerosol transmission
--most invasive disease caused by capsular type B
--produces IgA protease
--growth on chocolate agar requires factor V (NAD+) and factor X (hematin). Can also be grown with s. aureus, which provides factor V

2

What does Haemophilus influenza cause?

haEMOPhilus influenza causes:

Epiglottitis ("cherry red" in children)
Meningitis
Otitis media
Pneumonia

Nontypeable strains cause mucosal infections: otitis media, conjunctivitis, bronchitis

**H. influenza does *not* cause the flu

3

How do you treat Haemophilus influenza?

Treat mucosal infections with: amoxicillin +/- clavulanate
Treat meningitis with ceftriaxone; rifampin as prophylaxis in close contacts

4

Is there a vaccine for H. influenza?

Yes. It contains type B polysaccharide conjugated to diphtheria toxoid or other protein.

This vaccine is given between 2 and 18 months of age

5

What do we see for H. influenza on radiographic image?

Thickening of the epiglottis (*"thumbprint sign" on lateral neck radiograph

6

What are two gram (+) that form long, branching filaments that resemble fungi?

Actinomyces Israelii
Nocardia

7

Characteristics of Actinomyces israelii

--anaerobic
--not acid fast
--normal oral flora
--treat with penicillin
--causes oral/facial abscesses that drain through the sinus tracts, forms yellow "sulfur granules"

8

Characteristics of Nocardia

--aerobic
--acid fast
--found in soil
--treat with sulfonamides
--causes pulmonary infections in immunocompromised and cutaneous infections after trauma in immunocompetent

9

IgA protease

Enzyme that cleaves IgA

Secreted by:

Streptococcus pneumoniae
Haemophilus Influenzae
Neisseria meningitidis
Neisseria gonorrhoeae

10

Protein A

Binds Fc region of IgG and prevents opsonization by phagocytosis.

Expressed by S. aureus

11

M protein

Helps prevent phagocytosis.

Expressed by group A streptococci

12

Microbe that produces a blue-green pigment

Pseudomonas aeruginosa

"aerugella" is green

13

Microbe that produces yellow pigment

S. aureus

aureus is latin for gold

14

Microbe that produces red pigment

Serratia marcescens

think: marachino cherries

15

Microbe that forms yellow "sulfur" granules, which are composed of filaments of bacteria

Actinomyces israelii

think: Israel has yello sand

16

Which bugs are urease positive?

CHuck norris hates PUNKSS

Cryptococcus
Helicobater pylori

Proteus
Ureaplasma
Nocardia
Klebsiella
Staphylococcus epidermidis
Staphylococcus saprophyticus

17

The significance of catalase positive organisms

Catalase degrades hydrogen peroxide before it can be converted to microbicidal products (halide radicals) by myeloperoxidase.

People with chronic granulomatous disease have recurrent infections with catalase (+) organisms

18

What is chronic granulomatous disease (brief definition)

NADPH oxidase deficiency

19

What are some catalase positive organisms that are common in chronic granulomatous disease?

Peudomonas
Listeria monocytogenes
Aspergillus
Candida
E. Coli
S. aureus
Serratia marsescens
Nocardia

20

Clinical significance of encapsulated bacteria

These bacteria's capsule serves as an antiphagocytic virulence factor. They are opsonized, and then cleared by the spleen.

People without a spleen have a decreased opsonizing ability and are at increased risk for severe infections by encapsulated bacteria.

You should give S. pneumoniae, H. influenzae, and N. meningitidis vaccines.

21

What are examples of encapsulated bacteria?

SHiNE SKiS

Streptococcus pneumoniae
Haemophilus influenzaw
Neisseria meningitidis
E. Coli

Salmonella
Klebsiella
group b Strep