Bacteriology Flashcards
What is the pathophysiology of rheumatic fever?
Strep. pyogenes infection (pharyngitis or scarlet fever) –> anti- M protein Abs cross-react with heart muscle, as well as joint, skin, and brain.
Major Sx of Rheumatic Fever
- Myo- or pericarditis
- Erythema marginatum (rash)
- Arthritis
- Sydenham’s chorea
Culture test for GBS
CAMP test: GBS has a synergistic effect on hemolysis by S. aureus.
Diphtheria toxin: where is it encoded and what is its mechanism of action?
encoded by a β prophage.
inhibits protein synthesis via ADP ribosylation of EF-2.
What are the ABCDEFG’s of Corynebacterium?
ADP ribosylation Beta-prophage Corynebacterium Diphtheriae Elongation Factor-2 Granules (metachromatic - blue and red)
Gram (+) rods
Listeria
Clostridium
Bacillus
Corynebacterium
What is usually the best Tx for meningitis? (at least for Gram (+) cocci)
Cephalosporins
think “cephalus” = head = meningitis
Name all the categories of β-lactam Abx.
Penicillins (ampicillin, amoxicillin)
Cephalosporins (ceftriaxone)
Monobactams (aztreonam)
Carbapenems (Imipenem)
What are the 2 toxins of C. difficile?
Toxin A, enterotoxin, bind brush border
Toxin B, cytotoxin, causes pseudomembranous colitis
black eschar lesion
- causative agent
- virulence factors
- Bacillus anthracis
- lethal factor and edema factor
What is the main treatment for Hansen’s disease?
long-term dapsone
may be used in combo w/ rifampicin and clofazamine
What do dapsone and sulfonamide Abx have in common?
Both inhibit the production of dihydrofolinic acid in bacteria.
What are the differences between lepromatous and tuberculoid types of Hansen’s disease?
Lepromatous - diffuse skin lesions, low cell-mediated immunity, Th2 response
Tuberculoid - few skin lesions, high cell-mediated immunity, Th1 response
