B6-088 Gangrene Flashcards
catalase positive cocci in clusters
staphylococcus
beta hemolytic cocci in chains
S. pyogenes (GAS)
S. agalactiae (GBS)
anaerobic gram positive bacilli [3]
clostridium
actinomyces
propionibacterium
anaerobic gram negative bacilli [4]
bacteriodes
fusobacterium
prevotella
prophyromonas
GAS diseases of skin [3]
impetigo
erysipelas/cellulitis
necrotizing fasciitis
systemic diseases caused by GAS [4]
bacteremia
rheumatic fever
acute glomerulonephritis
streptococcal TSS
raised, bright red plaques with sharply defined borders
erysipelas
allows typing of GAS into different strains
M protein
what virulence factor of GAS helps the bacteria to “hide” from immune system?
hyaluronic acid capsule
toxin that causes GAS to form a superantigen (causes Scarlet fever and TSS)
Spe
Streptococcus pyrogenic exotoxin
GAS virulence factor that helps the bacteria spread in tissues
can sometimes be inactivated or mutated
hyaluronidase
GAS virulence factor that activates plasminogen to dissolve clots
streptokinase
DOC for cellulitis caused by GAS [2]
penicillin, ceftriaxone
DOC for TSS caused by GAS
penicillin + clindamycin
to suppress toxin production via 50S ribosome inhibition
cause 80% of skin/soft tissue infections
causes septic shock with high mortality
staphylococcus
SSSS is caused by toxins […] and […]
ETA and ETB
sudden fever followed by headache, sore throat, diffuse red rash and skin desquamation
can progress to shock within 48 hrs
TSS (staphy)
opsonizes bacteria and enhances phagocytosis
C3b
catalase +
coagulase +
beta hemolytic
mannitol fermentation +
S. aureus
catalase +
coagulase -
ALP +
urease +
novobiocin susceptible
S. epidermis
catalase +
coagulase -
ALP -
urease +
novobiocin resistant
S. saprophyticus
exogenous anaerobe
spore former
clostridium
places of heavy bacterial flora [2]
gingival crevice
colon
aerobes or facultative anaerobes can colonize and deplete the oxygen, providing and opportunity for […] to colonize
anaerobes
foul odor
sulfur granules
necrosis/abscess
previous antibiotic therapy
are all clues for [..]
anaerobic infection
most common anaerobe isolated from human infection
B. fragilis
bile resistant
bile-esculin agaar
B. fragilis
2nd most common anaerobic bacteria causing infections
normally cause orofacial and pleuropulmonary infections [2]
prevotella
prophyromonas
how to distinguish between prevotella and prophyromonas?
prevotella is saccharolytic (glucose fermentor)
prophyromonas is asaccharolytic
bacteriodes is penicillin […]
resistant
prophyromonas is vancomycin […]
sensitive
prevotella is vancomycin […]
resistant
[prevotella or prophyromonas]
growth on KV BAP
prevotella
is vanc resistant
[prevotella or prophyromonas]
no growth on KV BAP
prophyromonas
DOC for gram-negative anaerobes [2]
metronidazole
carbapenem
DOC for P. acnes
benzoyl peroxide/erythromycin
causes “lumpy jaw” abscesses
actinomycosis
forms abscesses with sulfur granules
forms molar tooth colonies
actinomycosis
treatment for actinomycosis
debridement + penicillin
part of a group of bacteria that causes displacement of normal bacterial flora
fishy odor on Whiff test
clue cells
mobiluncus
causes botulism
C. botulinum
causes pseudomembranous colitis
C. difficle
causes gas gangrene
C. perfringens
causes tetanus
C. tetani
major toxins of C. botulinum
A, B, E, F
major toxin of C. perfringens causing gas gangrene
alpha toxin
major toxin of C. tetani
tetanospasmin
inhibits nerve impulses causing flaccid paralysis
C. botulinum toxin
resistant to penicillin and associated with intraabdominal abscesses
bacteriodes
gram-negative
VancR
ferment glucose
sensitive to penicillin
prevotella
how does the presence of bacteriodes support the growth of penicillin susceptible bacteria?
bacteriodes secretes beta-lacatamase
**need a beta-lactamase inhibitor like amoxicillin-clavulanate
gram negative and grows in pairs (diplococcus)
N. gonorrhoeae
TSS is caused by
TSST-1 (superantigen)
main toxin of C. perfringens
alpha-toxin
does phospholipid hydrolysis causing cell lysis and tissue destruction
SNAP-25 is affected by […] toxin
botulinum toxin
VAMP is affected by […] toxin
tetanus
what organ systems does nocardiosis affect?
skin
lungs
central nervous system
