Card Set Information
Choclate agar with factors V and X
Tellurite plate, Loffler's media
MacConkeys agar - pink colonies
Lactose fermenting enterics
Charcoal yeast extract buffered with cysteine
Why are aminoglycosides ineffective against Clostrridium, bacteroides, and actinomyces?
These anaerobes and aminoglycosides require O2 to enter into bacterial cells.
What are the facultative intracellular bugs?
Some Nasty Bugs May Live FacultativeLy
What are the encapsulated bacteria?
Haemophilus influenzae type B
group B strep
Positive Quellung reaction
Urease positive bugs
Protein A MOA and organism
Binds Fc region of Ig. Prevents opsonization and phagocytosis
IgA protease MOA and organism
Cleaves IgA in order to colonize respiratory mucosa
H. Influenza type B
M protein MOA and organism
Group A streptococcus
What are the ADP ribosylating A-B toxins
- inactivates elongation factor
- ADP ribosylation of G protein stimulates adenylyl cyclase
: increase pumping of Cl- into gut and decrease Na+ absorption.
- Heat labile toxin stimulates Gs protein -> Adenylate cyclase
- Increases cAMP by inhibiting Ga1
Toxin of Clostridium perfringens
- a lecithinase that acts as a phospholipase to cleave cell membranes and causes gas gangrene.
Toxin of shigella
- cleaves host cell rRNA (inactivates 60S ribosome)
- enhances cytokine release causing hemolytic uremic syndrome
Group B streptococci, B-hemolytic
causes pneumonia, meningitis, and sepsis
Pregnant women + get intrapartum penicillin prophylaxis
Enterococci (Group D strep)
Normal colonic flora that are penicillin G resistant and cause UTI and subacute endocarditis
Grow in 6.5% NaCl and bile
Diphtheria toxin exotoxin encoded by B-prophage - inhibits protein synthesis via ADP ribosylation of EF-2
DX: via tellurite agar -> metachromatic granules
4 types of Clostridia
1. C. tetani- tetanospasmin causes spastic paralysis
2. C. botulinum- preformed heat-labile toxin that inhibits ACh release at NMJ
3. C. perfringens- a toxin(lecithinase) causes myonecrosis and hemolysis
4. C. difficile- AB toxin destroys cytoskeletal structure of enterocytes, causing pseudomembranous colitis.
gram positive rod
weakly acid fast and aerobic
causes pulmonary infection in immunocompromised patients
What does primary infection with Mycobacterium tuberculosis lead to
Ghon complex (hilar nodes/ ghon focus)
healing by fibrosis
progressive lung disease
Preallergic lymphatic or hematogenous dissemination -> dormant tubercle bacilli in several organs -> reactivation in adult life (CNS, Pott's, lymphadenitis, renal, GI)