Clostridium Flashcards
Name the most clinically relevant spp of Clostridium
C difficile
C perfringens
C tetani
C botulinum
C sordelii
C septicum
How do you get C tetani introduced into the body?
Through puncture wounds (from dirty nails/needles/barbed wire)
Contaminated surgical procedures (**infected umbilical stump after unsterile delivery**)
Disease caused by C tetani is mediated by the germination of spores, resulting in release of ___
tetanospasmin (tetanus toxin)
Tetanus toxin consists of two subunits, the __ subunit which binds motor neurons and facilitates retrograde transport to the spinal cord/brain stem, and the __ subunit which has proteolytic activity and cleaves GABA and Glycine (thereby inhibiting these inhibitory signals)
Tetanus toxin consists of two subunits, the B subunit which binds motor neurons and facilitates retrograde transport to the spinal cord/brain stem, and the A subunit which has proteolytic activity and cleaves GABA and Glycine (thereby inhibiting these inhibitory signals)
**in the Sketchy video: this is the scissors that are being pulled up by the monkey are the toxin with its proteolytic activity, and the people wearing GG suites - inhibition of gaba and glycine**
The action of the tetanus toxin leads to ___ (spastic/flaccid) paralysis
The action of the tetanus toxin leads to spastic paralysis
2 distinguishing features of tetanus are ___ and ___ (aka eveil smile)
The disease can also present with an arched back - contractions of back muscles - in a condition known as ___
2 distinguishing features of tetanus are lockjaw and risus sardonicus (aka evil smile)
The disease can also present with an arched back - contractions of back muscles - in a condition known as opisthotonos
Other forms of tetanus include: ___ which is localized to the spore inoculation site, cephalic tetanus and __ tetanus
Localized
Cephalic (Cranial nerve involvement: dysphagia, dysphonia, risus sardonicus)
Neonatal: (Trismus, inability to nurse, rigidity, apnea)
How do you Dx tetanus?
Mainly from H and P
(culture only useful if bacteria are cultured from the wound. the toxn don’t got no detectable antibodies)
How do you treat tetanus?
Clean or debride wound
Intramuscular tetanus immunoglobulin (antitoxin)
Tetanus vaccine at a different site
Maintain airway, treat hemodynamic instability, administer sedatives, muscle relaxants
Rx drug: Metronidazole (preferred) or penicillin
Unlike tetanus, the botulinim toxin targets the ___ at the NMJ >> affects peripheral voluntary and autonomic cholinergic receptors >> results in ___ (spastic/flaccid)
Unlike tetanus, the botulinim toxin targets the ACh receptors at the NMJ >> affects peripheral voluntary and autonomic cholinergic receptors >> results in flaccid paralysis
What kind of toxin (heat labile or otherwise) is C botulinim toxin?
Botulinum toxin is heat labile, but resistant to degradation by enzymes of GI tract
There are generally 4 catgories of Botulism. Name them.
Foodborne botulism
Infant botulism
Wound botulism
Inhalational botulism
___ botulism results from ingestion of pre-formed toxin from improper canning/preservation
Foodborne
**note that the toxin is already in the improperly canned food**
Infants can also get foodborne botulism by ingesting ___. This typically occurs following exposure to ___. Signs include poor feeding , hypotonia, drooling and ptosis
Infants can also get foodborne botulism by ingesting spores. This typically occurs following exposure to wild honey or other home-canned foods. Signs include poor feeding , hypotonia, drooling and ptosis
Wound botulism results from ___
What are the implications of black tar heroin use in wound botulism?
Wound botulism results from contamination of wound or otherdead tissue by spores
Black tar heroin: basically heroin mixed with come extra stuff to preserve it during transport from wherever. When the heroin is prepared, the cooking doesn’t kill the C botulinum spores which can germinate later. Skin popping creates an anaerobic env for the spores to grow and produce toxin resulting in manifestation of disease
Inhalation botulism can result from __
Aerosolized Botulinum toxin
The main clinical features of botulinum toxin involve cranial neuropathies with ___ progressing to ___
Cranial neuropathies >> symmetric, descending paralysis >> respiratory failure
How would you Dx C botulinum infection?
Mainly from H and P
Culture useful if +ve and if you get the bug from implicated food
Toxin can be detected in serum, feces or food
Botulism treatment includes __ or penicillin/metronidazole and ventilatory support
Botulism Rx:
Ventilatory support
Botulinum antitoxin
Metronidazole or penicillin
Botulism can be prevented by ___
maintaining food at an acidic pH or at 4oC or colder (prevent germination of spores)
preformed toxin destroyed by heating to 80oC for 20 minutes
___ is found in the soil and GI tract and produces a double zone of hemolysis on blood agar
C perfringens is found in the soil and GI tract and produces a double zone of hemolysis on blood agar
Which bug is this?
C perfringens
Food poisoning from C perfringens is mainly ass’d with ___
C perfringens infection results in soft tissue infections, including ___ (aka gas gangrene)
Other complications that can arise include ___ and bacteremia
Food poisoning from C perfringens is mainly ass’d with contaminated meat products
C perfringens infection results in soft tissue infections, including myonecrosis (aka gas gangrene - remember the gas coming out of the soldier’s crashed motorcycle)
Other complications that can arise include massive hemolysis (think about the tomatoes in sketchy) and bacteremia
The diarrhea caused by C perfringens food poisoning is due to a __ and is __ (watery/bloody) and usually self limited
The diarrhea caused by C perfringens food poisoning is due to a heat labile enterotoxin (alpha toxin) and is watery and usually self limited
The main manifestation of C perfringens infection besides food poisoning is ___. Patients may present with severe pain progressing to edema, pallor and may have hemorrhagic bullae or subcutaneous emphysema (aka gas)
Another Clostridium bug that can cause a similar infection is ___
The main manifestation of C perfringens infection besides food poisoning is C perfringens myonecrosis. Patients may present with severe pain progressing to edema, pallor and may have hemorrhagic bullae or subcutaneous emphysema (aka gas)
C septicum (note that this is spore mediated, not toxin mediated like perfringens)
How do you Dx C perfringens infection?
Which bug would you think of if the culture has spores vs lacks spores?
How do you treat C perfringens infection?
Dx: microscopy. bugs observed but no RBCs or WBCs
+spores: C septicum
-spores: C perfringens
Rx: Penicillin + Clindamycin for toxin syntheis inhibition, surgical debridement
___ is the most common cause of antibiotic ass’d diarrhea
C difficile
Describe the steps leading to C diff infection
Disruption of normal gut flora (due to antibiotics mostly) >> colonization with C diff >> production of Toxins A and B >> pseudomembranous colitis
The clinical manifestations of C diff infection include ___ diarrhea, and cramping abdominal pain. In its most severe form, C diff infection manifests with __, bowel perforation and even death
The clinical manifestations of C diff infection include profuse watery or green mucoid, foul smelling diarrhea, and cramping abdominal pain. In its most severe form, C diff infection manifests with toxic megacolon, bowel perforation and even death
How do you Dx C diff?
PCR amplifiction of toxin genes
Culture, immunoassays + cytotoxicity assays
(2 step testing: PCR/antigen + toxin immunoassay)
How do you classify severity of C diff infection based on WBCs and creatinine? (what’s mild/moderate vs severe vs fulminant)
Mild-Moderate:
WBC <15,000 cells/mm3
Creatinine <1.5x baseline
–
Severe:
WBC ≥15,000 cells/mm3
Cr > 1.5x baseline
–
Fulminant (infection plus not doing well at all):
Severe CDI PLUS
Hypotension or shock , ileus, megacolon, perforation
Complete the table below for C diff treatment based on disease severity
Remember the Sketchy van and metro train
How do you treat C diff recurrence?
1st time:
If metronidazole used first, use vanc for 10 days
If vanc used first, use it longer (prolonged taper) or switch to fidaxomicin
2nd time:
Vanc taper or fidaxomicin
Fecal transplant
