Lecture 16 Flashcards
Shape and stain of clostridium
GramPos rods with rounded ends
In pairs or short chains (shorter than bacillus though)
How does clostridium survive
Endospores
Clostridium O2 needs
Anaerobic
C. botulinum clinical manifestation
18-24 hour incubation
Bilateral CN palsy with progressive descending flaccid paralysis
Death via heart and diaphragm involvement
Floppy baby syndrome (honey)-botulism inhabits the gut before other native flora can
Main ways. C. botulism is spread
Home canned foods
Infected wounds
Black tar heroin
How does C. botulism cause illness
From phage conversion
B part binds motor end plates
A part blocks release of acetylcholine –> flaccid paralysis
C. botulism treatment
Heptavalent antitoxin
Administered early
No antibiotics because it’s an intoxication
C. tetani clinical manifestation
4 days-4 weeks incubation
Rigid paralysis first of jaws then back
Eventually death with respiration impairment
C. tetani pathogenesis
AB toxin, plasmid encoded
Tetanospasm for retrograde transport to CNS
Binds irreversibly to inhibitory neurons
Prevents GABA release
C. tetani control
Tetanus immunoglobulin
Antitoxin works only if given early enough
Early trach
Muscle relaxants
Metronidazole to reduce bacterial population
Clostridium perfringens causes what?
Gas gangrene
1-3 days until infected wound begins suppurating
Can also be a food poisoning
Commonly from traumatic tissue injury if anaerobic tissue conditions are present
Clostridium perfringens pathogenesis
Extracellular enzyme destroys tissues
Lecithinase
Hyaluronidase, collegenase
Some produce enterotoxin (diarrhea like B. cereus)
What is main way tetanus is now spread in US
IV drug use
Tattoos
Why does C. perferingens cause gas in tissues?
Gas from fermentation of destructed tissues
Compresses blood flow and creates more necrosis
C. perfringen control
Prompt surgical debridement
Metronidazole, PCN, clindamycin
C. diff causes
Usually after 4-10 days of broad spectrum oral antibiotic use
Also with excessive PPI
What does the inside of bowel look like with C diff?
Leukocytes penetrate CT layer and forms a gray, white, yellow pseudomembrane (pseudomembrane colitis)
What is main spread of C diff
Nosocomial
C diff pathogenesis
2 toxins:
Enterotoxin (toxin A)-fluid accumulation
Cytotoxin (toxin B)-kills gut epithelium
C diff control
Stop previous Abx if you can
Fecal transplant form healthy donor
Vanc, metronidazole
Fidaxomycin
Actinomyces israelii shape and stain
G+, branching, fragmenting filaments
ONLY ONE THAT’S A FILAMENT
Actinomyces israelii O2 requirement
Facultative anaerobe
Actinomyces israelii clinical manifestations
Swollen, pyogenic draining abscess (lumpy jaw)
Can manifest in face, lungs, abdomen, skin
Sulfur granules in collected pus
Actinomyces israelii is found where?
Part of normal mouth and gut flora
Oral-from tooth extraction or poor hygiene
Lungs-aspiration
Abdomen-perforation
Actinomyces israelii mainly affects who?
Immunocompromised PTs
Actinomyces israelii control
Surgical drainage if possible
PenG for 6-12 months
Tetra or other if PT is allergic
Prophylactic if PT has recurring infection
Nocardia asteroides stain?
Looks like actinomycete morphology
Also has short mycolic acids so partially acid-fast
Nocardia asteroides O2 requirement
Aerobic
Nocardia asteroides lives were
Surface soil
Nocardia asteroides clinical manifestations
Lobar pneumonia in alcoholics of immunocompromised
Abscess formation in lung
May spread to CNS and brain (meningitis, brain abscess)
Also on foot from soil
Nocardia asteroides control
SxT
Aeromonas and Plesiomonas shape and stain
GramNeg rod
Aeromonas and Plesiomonas O2 requirement
Anaerobe
Aeromonas and Plesiomonas is found where?
Aquatic environment
Aeromonas and Plesiomonas clinical manifestation
Cholera-type (watery) diarrhea
Dysentery type-blood and mucous
Also cellulitis and myonecrosis
Aeromonas and Plesiomonas transfer
Infected sea food
Fish hook
Scuba equipment (biofilms)
Aeromonas and Plesiomonas pathogenesis
LPS, PG
ACT toxin-lyses cells and ↑ cAMP
Pili for attachment to gut epithelium
Aeromonas and Plesiomonas treatment
Avoid undercooked seafood
Diarrhea-usually self limiting
Immunocompromised and wound cellulitis Tx with SxT, clinda
