Clostridiia Flashcards
Two Major Bacterial Disease Mechanisms
- Toxin Mediated
- no organisms required
- ex botulism or Staph A. Food poisoning - Invasion
- bacterial tissue invasion
- overactive inflammation
Types of Toxin Mediated Disease
- Pre-Formed Toxin
-Bacteria colonize external environment (like food)
-produce toxins
-toxins enter person (i.e. Ingestion)
Example: Botulism - Bacterial Invasion
- ingestion of microorganisms-
- colonization in gut
- toxin secreted while organism is in body
Clostridium (General Facts)
Obligate Anaerobe
Gram Positive Rods
SPORES
Catalase Negative
Oxidase Negative
Many species
Where is C. Tetani Found? And other epi
Found in SOIL
One serological type
Very rare- usually non-immunized ind
60% fatality :0
What is Tetanus Toxin and how does it work?
Neurotoxin with A and B subunits
Inhibit release of n.transmitter GLYCINE and GABA
What does Tetanus cause?
- > SPASTIC PARALYSIS
- convulsive contractions
What are the clinical syndromes of Tetanus?
Violent muscle spasms (predominantly flexor muscles)
If involves respiratory muscles can lead to respiratory failure
Aspiration if pharyngeal muscles involved
Tetanus pertinent negatives?
NO FEVER
NO SENSORY DEFICIT
How do clinicians diagnose Tetanus?
Mostly clinically
Organisms rarely seen in wound site
Treat Tetanus
*Human Tetanus immunoglobulin
Penicillin plus wound cleaning
How are we gonna prevent Mr. Tetanus?
Immunize with TOXOID
-3 doses in first 6 months of life
Booster every 10 years
Clostridium spore location
Tetani: TERMINAL SPORE (diagnostic)
Botulinum: Subterminal oval spore
Botulism epi
Very low incidence
Found in soil
Spores very resistant to heat and chemicals
Can grow in CANNED FOOD
Can infect wounds
What is Botulism Toxin?
HEAT LABILE protease
But resists acid
Extremely POTENT
7 types
How does Botulism Toxin cause disease?
Absorbed by intestines
Carried via blood to peripheral nerve synapses
Enters NERVE CELLS by receptor mediated endocytosis
BLOCKS ACETYLCHOLINE RELEASE into synapse
How does botulism manifest clinically?
18-36 hr incubation
Weakness or FLACCID PARALYSIS
SYMMETRICAL
Dilated pupils, dry throat
May affect respiration
What are the Pertinent negatives for botulism?
NO FEVER
NORMAL MENTAL STATUS
NO SENSORY DEFICIT
How do we diagnose Botulism?
Clinical
Usually can’t culture (preformed toxin)
Detect toxin in serum
Detect source toxin in food
What other disease look like botulism?
Myasthenia Gravis
Gillian Barre Syndrome
-ascending paralysis
Prevention
No vaccine
COOK CANNED FOOD
What is Infant Botulism?
1-8 months of age
Honey common source
Babies eat bacteria and toxin formed in the gut
Subtle symptoms (constipation, weak head control)
How do you treat Botulism?
Early: remove toxin from stomach
ANTITOXIN
-toxin specific, remember there’s different types
Clostridium Difficile EPI
Common cause of antibiotic resistant diarrhea
Found in GI tract of some health individuals (esp those in hospital)
How does C. Diff cause disease?
When normal flora is suppressed (i.e. Antibiotic therapy)
-> C. Diff able to colonize and grow
Produces exotoxins
What are the toxins produced by C. DIff?
Exotoxin A:
- enterotoxin
- binds to gut receptor
EXOTOXIN B:
- cytotoxin
- damages colonic mucosa ->bleeding
- leads to PSEUDOMEMBRANE
How does C. Diff manifest?
Diarrhea
Pseudomembrane - Yellow/white plaque
PMN in stool
Blood in stool
How do we Diagnose C. Diff?
History of antibiotic use
Exotoxin B in stool
ELISA for toxins
Stool culture doesn’t mean disease
How do you treat C. Diff?
Stop offending antibiotics
Treat with METRONIDAZOLE or VANCOUVER
What in the world is Clostridium Perfringens?
Causes GAS GANGRENE
Hallmark tissue necrosis
Found in soil and Gi
What are the two manifestations of C. Perf?
- Gas Gangrene
- Invasive rapidly progressing
- requires surgery to treat - Self limiting diarrhea
How does Gas Gangrene happen?
Tissue infection
Anaerobic environment
Toxins necrose tissue
Releases gas (H2 and CO2)
What are the important C. Perf toxins?
ALPHA TOXIN - lecithinase
-damages host cell membrane
Collagenase and Hyaluronidase
-break down extracellular protein matrix
How does C. Perf poison us through food?
Growth in food
Ingest bacteria
Pre-synthesized enteroxtins released
How does Gas Gangrene Manifest?
Dependent on anatomy and location of infection
Cellulitis
necrotizing cellulitis
Necrotizing fasciitis
What does C. Perf food poisoning look like?
Ab cramps
Watery diarrhea within 8-24 hours
Clinical diagnosis for C. Perf?
Crepitus (from gas)
Discoloration and edema
Special culture
How would you treat gangrene?
SURGERY and wound cleaning
Penicillin to kill all that remains
Hyperbaric oxygen if available
