Anaerobes Flashcards
T/F The endogenous anaerobes are sporulators
FALSE The exogenous anaerobes are sporulators
How does actinomyces appear on gram stain?
Gram positive filamentous rod
Actinomyces is commonly found in what four areas in the body?
- Oral cavity
- Respiratory tract
- GU tract
- GI tract
When the mucosa is disrupted, actinomyces causes _____ lesions
Granulomatous lesions
What is the treatment for Actinomyces infection?
Beta-lactams + debridement
How do Propionobacterium on gram stain?
Gram positive bacilli
What three disorders do Propionobacterium cause?
- Acne
- Infection of prosthetics
- Endopthalmitis
What are the treatment options for Propionobacterium infection?
- Benzoyl Peroxide
- Oral erythromycin or clindamycin
- Retinoic acid
How Bacteriodes appear on gram stain?
Gram negative bacilli (some pleomorphism)
Bacteriodes are normal flora of the GI tract, but are also _____ pathogens, primatily in the _____
Opportunistic pathogens of the peritoneal cavity
T/F Bacteriodes are resistant to many different antibiotics
TRUE
Including Beta-lactams, aminoglycosides, many developing resistance to erythromycin and tetracycline
What are the clinical signs of an anaerobic infxn
- Foul-smelling discharge
- Due to short chain FA metabolism products
- Gas in tissues
- Production of CO2 and H2
- Rotten eggs smell
T/F The spores of exogenous anaerobes cause disease
FALSE
The spores must germinate and form vegetative cells to cause disease. This requires an anaerobic environment
How does Clostridium tetani appear on gram stain?
Gram positive rods with terminal endospores (tennis rackets)
What are the two toxins produced by C. tetani?
- Tetanolysin
- Hemolysin, no role in pathogenesis
- Tetanospasmin (Tetanus Toxin)
- Spasmogenic, causes classical symptoms of tetanus
Tetanospasmin (Tetanus Toxin) inhibits the release of the neurotransmitters _____ and _____. What does this cause?
- Blocks release of GABA and glycine
- Prevents relaxation of mm.
- Muscle rigidity, convulsions, spastic paralysis
- Prevents relaxation of mm.
What is the pattern of paralysis in tetanus?
Descending, spastic paralysis
What are the treatment options for tetanus?
- Local debridement
- Supportive measures
- Penicillin or metronidazole to kill bacteria, but may not improve prognosis
- Passive immunity with human IG to neutralize toxin if not vaccinated
What kind of vaccine is available for tetanus?
Toxoid vaccine
What are the three forms of disease caused by C. botulinum?
- Food poisoning
- Ingestion of preformed toxin
- Wound botulism
- Infection of wound with spores
- Infant botulism
- Germination of ingested spores
Botulism is caused by _____ produced by C. botulinum
Neurotoxin
What substance produced by C. botulinum is known as the most toxic substance on earth?
Toxin H
C. botulinum toxin, in contrast to C. tetani toxin, causes _____ paralysis
Flaccid paralysis (Spastic caused by C. tetani toxin)
The symptoms of of foodborne botulism present 12-36 hours after ingestion. What are they?
- Weakness/dizziness
- Vision changes
- Dry mouth
- Abdominal pain
- No fever
- Bilateral flaccid paralysis
What are the treatment options for C. botulinum disease?
- Passive immunization
- Supportive care (ventilator)
The type A strain of C. perfringens can cause what two diseases?
Gas gangrene and food poisoning
______ is an acute disease with poor prognosis caused by C perfringens. It is associated with war wounds, which impairs blood flow to the area, providing an anaerobic environment for the organism.
Gas gangrene
Muscle infected with Gas gangrene (C. perfringens) show what four characteristics?
- Discoloration (purple mottling)
- Edema
- Foul smelling exudate
- Gas bubbles
- From anaerobic fermentation
What is the treatment for C. perfringens gas gangrene?
Debridement, exposure of exposed area to oxygen
What is the most common cause of food poisoning in the USA? What kind of food is this organism found in
- C. perfringens
- Meat/meat products
T/F C. perfringens food poisoning lasts only 24 hours
TRUE
Watery diarrhea, cramps, abdominal pain (and rarely fever/nausea/vomiting) last only 24 hours in C. perfringens food poisoning
T/F C. difficile is an anaerobe that is a true pathogen
FALSE
C. difficile is a member of your normal flora
How is C. difficile infection acquired?
Broad spectrum antibiotic use kills normal flora, allowing C. diff overgrowth
What are the two toxins produced by C. diff. responsible for disease? What do they do?
- Enterotoxin (A)
- Neutrophil chemoattractant
- Destroys tight junctions, creates permeability (cytopathic
- Cytotoxin (B)
- Cytopathic
T/F: C. diff. spores can persist in a room for weeks to months, and can survive temperatures and disinfectant
TRUE
What is the most reliable method of diagnosis for C. diff. infection?
PCR for toxins in stool
What are the treatment options for C. difficile infection?
- Stop use of abx
- Metronidazole (Moderate disease)
- Vancomycin (Severe disease)
- Fecal transplant has been shown to be successful
