Anaerobes

Question 1

T/F The endogenous anaerobes are sporulators

Answer 1

FALSE The exogenous anaerobes are sporulators

Question 2

How does actinomyces appear on gram stain?

Answer 2

Gram positive filamentous rod

Question 3

Actinomyces is commonly found in what four areas in the body?

Answer 3

• Oral cavity
• Respiratory tract
• GU tract
• GI tract

Question 4

When the mucosa is disrupted, actinomyces causes _____ lesions

Answer 4

Granulomatous lesions

Question 5

What is the treatment for Actinomyces infection?

Answer 5

Beta-lactams + debridement

Question 6

How do Propionobacterium on gram stain?

Answer 6

Gram positive bacilli

Question 7

What three disorders do Propionobacterium cause?

Answer 7

• Acne
• Infection of prosthetics
• Endopthalmitis

Question 8

What are the treatment options for Propionobacterium infection?

Answer 8

• Benzoyl Peroxide
• Oral erythromycin or clindamycin
• Retinoic acid

Question 9

How Bacteriodes appear on gram stain?

Answer 9

Gram negative bacilli (some pleomorphism)

Question 10

Bacteriodes are normal flora of the GI tract, but are also _____ pathogens, primatily in the _____

Answer 10

Opportunistic pathogens of the peritoneal cavity

Question 11

T/F Bacteriodes are resistant to many different antibiotics

Answer 11

TRUE

Including Beta-lactams, aminoglycosides, many developing resistance to erythromycin and tetracycline

Question 12

What are the clinical signs of an anaerobic infxn

Answer 12

• Foul-smelling discharge
  
  • Due to short chain FA metabolism products
• Gas in tissues
  
  • Production of CO2 and H2
  • Rotten eggs smell

Question 13

T/F The spores of exogenous anaerobes cause disease

Answer 13

FALSE

The spores must germinate and form vegetative cells to cause disease. This requires an anaerobic environment

Question 14

How does Clostridium tetani appear on gram stain?

Answer 14

Gram positive rods with terminal endospores (tennis rackets)

Question 15

What are the two toxins produced by C. tetani?

Answer 15

• Tetanolysin
  
  • Hemolysin, no role in pathogenesis
• Tetanospasmin (Tetanus Toxin)
  
  • Spasmogenic, causes classical symptoms of tetanus

Question 16

Tetanospasmin (Tetanus Toxin) inhibits the release of the neurotransmitters _____ and _____. What does this cause?

Answer 16

• Blocks release of GABA and glycine
  
  • Prevents relaxation of mm.
    
    • Muscle rigidity, convulsions, spastic paralysis

Question 17

What is the pattern of paralysis in tetanus?

Answer 17

Descending, spastic paralysis

Question 18

What are the treatment options for tetanus?

Answer 18

• 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

Question 19

What kind of vaccine is available for tetanus?

Answer 19

Toxoid vaccine

Question 20

What are the three forms of disease caused by C. botulinum?

Answer 20

• Food poisoning
  
  • Ingestion of preformed toxin
• Wound botulism
  
  • Infection of wound with spores
• Infant botulism
  
  • Germination of ingested spores

Question 21

Botulism is caused by _____ produced by C. botulinum

Answer 21

Neurotoxin

Question 23

What substance produced by C. botulinum is known as the most toxic substance on earth?

Answer 23

Toxin H

Question 24

C. botulinum toxin, in contrast to C. tetani toxin, causes _____ paralysis

Answer 24

Flaccid paralysis (Spastic caused by C. tetani toxin)

Question 25

The symptoms of of foodborne botulism present 12-36 hours after ingestion. What are they?

Answer 25

* Weakness/dizziness * Vision changes * Dry mouth * Abdominal pain * No fever * Bilateral flaccid paralysis

Question 26

What are the treatment options for C. botulinum disease?

Answer 26

* Passive immunization * Supportive care (ventilator)

Question 27

The type A strain of C. perfringens can cause what two diseases?

Answer 27

Gas gangrene and food poisoning

Question 28

\_\_\_\_\_\_ 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.

Answer 28

Gas gangrene

Question 29

Muscle infected with Gas gangrene (C. perfringens) show what four characteristics?

Answer 29

* Discoloration (purple mottling) * Edema * Foul smelling exudate * Gas bubbles * From anaerobic fermentation

Question 30

What is the treatment for C. perfringens gas gangrene?

Answer 30

Debridement, exposure of exposed area to oxygen

Question 31

What is the most common cause of food poisoning in the USA? What kind of food is this organism found in

Answer 31

* C. perfringens * Meat/meat products

Question 32

T/F C. perfringens food poisoning lasts only 24 hours

Answer 32

TRUE Watery diarrhea, cramps, abdominal pain (and rarely fever/nausea/vomiting) last only 24 hours in C. perfringens food poisoning

Question 33

T/F C. difficile is an anaerobe that is a true pathogen

Answer 33

FALSE C. difficile is a member of your normal flora

Question 34

How is C. difficile infection acquired?

Answer 34

Broad spectrum antibiotic use kills normal flora, allowing C. diff overgrowth

Question 35

What are the two toxins produced by C. diff. responsible for disease? What do they do?

Answer 35

* Enterotoxin (A) * Neutrophil chemoattractant * Destroys tight junctions, creates permeability (cytopathic * Cytotoxin (B) * Cytopathic

Question 36

T/F: C. diff. spores can persist in a room for weeks to months, and can survive temperatures and disinfectant

Answer 36

TRUE

Question 37

What is the most reliable method of diagnosis for C. diff. infection?

Answer 37

PCR for toxins in stool

Question 38

What are the treatment options for C. difficile infection?

Answer 38

* Stop use of abx * Metronidazole (Moderate disease) * Vancomycin (Severe disease) * Fecal transplant has been shown to be successful