Flashcards in Special Culture/features of bacteria Deck (17)
Which media does H. influenza grow on?
Chocolate agar with factors NAD+ and hematin
Which media does M. tuberculosis grow on?
Which media does M. pneumonia grow on?
Eaton agar--requires cholesterol
Lactose-fermenting enterics media?
Pink colonies on MacConkey agar
3 obligate aerobe bacteria
Nagging Pests Must Breathe
2. Pseudomonas aeruginosa
3. Mycobacterium tuberculosis--this is why TB is often found in the apices of the lungs where the PO2 is highest
3 obligate anaerobe bacteria
Anaerobes *Can't *Breath *Air
What makes anaerobes obligate?
General clinical characteristics of obligate anaerobes
Which antibiotics are ineffective towards obligate anaerobes?
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
Two obligate intracellular bugs
Rickettsia and chlamydia --this is why they don't gram stain very well
Facultative intracellular bacteria (8)
*Some *Nasty *Bugs *May *Live *Facultative**LY
Encapsulated bacteria (7)
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?
Haemophilus influenza type B
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
"you need PLACESS for your *cats"
How does catalase work?
Which patients are at risk for infection from catalase-positive organisms?
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
Encapsulated bacteria vaccines:
how do they work? for what purpose? why can't a polysaccharide antigen be used alone?
3 examples: "Past Medical History"
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
Pigment producing bacteria:
Actinomyces israelli is YELLOW
S. aureus is GOLD
pseudomonas is BLUE-GREEN
Serratia marcescens is RED
Protein A virulence factor
Binds Fc region on IgG.
Prevents opsonization and phagocytosis
Expressed by S. aureus
Secreted by? (4) SHiNe
Enzyme that cleaves IgA
Secreted by S. pneumoniae, HiB, and Neisseria (SHiN) in order to colonize the respiratory mucosa