Special Culture/features of bacteria

Question 1

Which media does H. influenza grow on?

Answer 1

Chocolate agar with factors NAD+ and hematin

Question 2

Which media does M. tuberculosis grow on?

Answer 2

Lowenstein-Jensen agar

Question 3

Which media does M. pneumonia grow on?

Answer 3

Eaton agar–requires cholesterol

Question 4

Lactose-fermenting enterics media?

Answer 4

Pink colonies on MacConkey agar

Question 5

3 obligate aerobe bacteria

Nagging Pests Must Breathe

Answer 5

1. Nocardia
2. Pseudomonas aeruginosa
3. Mycobacterium tuberculosis–this is why TB is often found in the apices of the lungs where the PO2 is highest

Question 6

3 obligate anaerobe bacteria

Anaerobes *Can’t *Breath *Air

Answer 6

1. Clostridium
2. Bacteroides
3. Actinomyces

Question 7

What makes anaerobes obligate?
General clinical characteristics of obligate anaerobes
Which antibiotics are ineffective towards obligate anaerobes?

Answer 7

1. Obligate anaerobes lack catalase and/or superoxide dismutase and are thus susceptible to oxidative damage.
2. Generally foul-smelling, difficult to culture, and produce gas (CO2 and H2) in tissue
3. Aminoglycosides (aminO2glycosides) require oxygen to enter into bacterial cell

Question 8

Two obligate intracellular bugs

Answer 8

Rickettsia and chlamydia –this is why they don’t gram stain very well

Question 9

Facultative intracellular bacteria (8)

*Some *Nasty *Bugs *May *Live *Facultative**LY

Answer 9

Salmonella
Neisseria
Brucella
Mycobacterium
Listeria
Francisella
Legionella
Yersina pestis

Question 10

Encapsulated bacteria (7)
***SHiNE SKiS
How does the capsule assist the bacteria?
How can the capsule be used in vaccines?
How are encapsulated bacteria cleared by body?
Who is at risk for infection from encapsulated bacteria?

Answer 10

Streptococcus pneumoniae 
Haemophilus influenza type B
Neisseria meningitidis
E. Coli
Salmonella 
Klebsiella pneumoniae
Group B Strep

1. Capsule serves as an antiphagocytic virulence factor
2. Capsule + protein conjugate serves as an antigen in vaccines
3. Opsonized and cleared by spleen
4. Asplenic patients are at risk for severe infections from encapsulated organisms

Question 11

Catalase-positive organisms
“you need PLACESS for your *cats”
How does catalase work?
Which patients are at risk for infection from catalase-positive organisms?

Answer 11

Pseudomonas
Listeria
Aspergillus
Candida 
E. Coli
Staph aureus
Serratia

Catalase degrades H2O2 before it is converted to microbicidal products by the enzyme myeloperoxidase.
People with CHRONIC GRANULOMATOUS DISEASE (NADPH peroxidase deficiency) have recurrent infections with catalase + organisms

Question 12

Encapsulated bacteria vaccines:
how do they work? for what purpose? why can’t a polysaccharide antigen be used alone?
3 examples: “Past Medical History”

Answer 12

1. Some vaccines contain a polysaccharide capsule conjugated to a carrier protein
2. This enhances immunogenicity by promoting T-cell activation and subsequent class switching
3. Polysaccharide antigen alone cannot be presented to T-cells
   Examples: Penumococcal vaccine, H. influenza type B vaccine, Meiningococcal vaccine

Question 13

Urease-positive bugs

“CHUNKSS”

Answer 13

Cryptococcus
H. pylori
Ureaplasma
Nocardia
Klebsiella
Staph epidermis
Staph saprophyticus

Question 14

Pigment producing bacteria:
Actinomyces israelii
S. aureus
Pseudomonas aeruginosa
Serratia marcescens

Answer 14

Actinomyces israelli is YELLOW
S. aureus is GOLD
pseudomonas is BLUE-GREEN
Serratia marcescens is RED

Question 15

Protein A virulence factor

Answer 15

Binds Fc region on IgG.
Prevents opsonization and phagocytosis
Expressed by S. aureus

Question 16

IgA protease

Secreted by? (4) SHiNe

Answer 16

Enzyme that cleaves IgA

Secreted by S. pneumoniae, HiB, and Neisseria (SHiN) in order to colonize the respiratory mucosa

Question 17

M protein

Answer 17

Helps prevent phagocytosis.

Expressed by Group A Streptococci