Gram Positive/Negative Anaerobes

Question 1

Clostridium perfringens diseases

Answer 1

• Gas gangrene
• Food poisoning
• Intra-abdominal infection

Question 2

Clostridium tetani diseases

Answer 2

Tetanus

Question 3

Clostridium botulinum diseases

Answer 3

Botulism

Question 4

Clostridium difficile diseases

Answer 4

Nosocomial GI infection

Question 5

Propionobacterium acnes diseases

Answer 5

Acne

Infection of prosthetics

Question 6

Actinomyces diseases

Answer 6

Abscess formation

Question 7

Peptostreptococcus diseases

Answer 7

Mixed contiguous infections

Question 8

What are the spore forming Gram positive anaerobes?

Answer 8

Clostridium

Question 9

What are the non-spore forming Gram positive anaerobes?

Answer 9

P. acnes
Actinomyces
Peptostreptococcus

Question 10

What are the Gram negative anaerobes?

Answer 10

Bacteriodes
Fusobacterium
Prevotella
Porphyromonas

Question 11

Bacteroides fragilis diseases

Answer 11

Abscess formation with mixed infection

Question 12

Fusobacterium nucleatum diseases

Answer 12

Pneumonia or lung abscess with potent endotoxin

Liver abscess

Question 13

Fusobacterium necrophorum diseases

Answer 13

Metastatic infection that is due to high virulence because of its endotoxin

Question 14

Prevotella diseases

Answer 14

Female GU tract infections
Oral and GI tract infections

Often causes mixed infections

Question 15

Porphyromonas diseases

Answer 15

Oral and periodontal infections

Question 16

What anaerobes cause mixed infections?

Answer 16

Bacteroides fragilis
Prevotella

C. perfringens
Peptostreptococcus

Question 17

What is the best antibiotic for anaerobic Bacteroides infection?

Answer 17

Metronidazole

Question 18

What is the main toxin of C. perfringens and what is its function?

Answer 18

Alpha Toxin.

It lyses inflammatory cells and protects C. perfringens
from attack by WBCs which leads to gas gangrene where no live WBCs can be found in the blisters.

Question 19

What is the onset of gas gangrene?

Answer 19

Rapid onset

Question 20

How does C. perfringens cause gas gangrene?

Answer 20

Effects of the exotoxins released:
– necrosis of muscle and skin 
– tense edema
– bullae formation
– gas formation

Question 21

How does C. perfringens cause food poisoning?

Answer 21

Spores contaminate food which is ingested and enterotoxin produced following germination of large numbers of organisms leads to disease 8-24 hrs later

Question 22

How is C. tetani spread?

Answer 22

– puncture wounds

– burns

Question 23

How does C. tetani cause tetanus?

Answer 23

Releases tetanospasmin, a neurotoxin that blocks postsynaptic inhibition spinal motor reflexes (GABA) leading to spasmotic contractions

Question 24

What does C. tetani look like under the Gram stain?

Answer 24

Tennis rackets

Question 25

What is the manifestation of C. tetani infection?

Answer 25

Axonal transport of toxin with variable manifestations that develops into generalized tetanus preceded most commonly by trismus

Question 26

What is a frequent source of C. botulinum infection?

Answer 26

Home canning of fruits/vegetables/fish

Question 27

What causes botulism?

Answer 27

Preformed toxin with spore contamination. It does not require spore germination.

Question 28

What are some manifestations of botulism?

Answer 28

Descending paralysis (flaccid) - 1st symptoms are lack of eye movement

Question 29

What is the major mechanism for C. difficile infection?

Answer 29

Patients in hospitals on antibiotics

Question 30

What is megacolon?

Answer 30

Megacolon - colon can enlarge and dilate leading to | perforation that could kill patient

Question 31

How does C. difficile cause its disease?

Answer 31

It produces and enterotoxin and a cytotoxin

Question 32

What does C. septicum cause?

Answer 32

Nontraumatic myonecrosis and bacteremia

Question 33

What does C. sordellii cause?

Answer 33

Fatal toxic shock syndrome following medical | abortions and natural child birth

Question 34

What infection is Actinomyces associated with?

Answer 34

Slow growing- abscess forming in cervicofacial, thoracic, pelvic, intraabominal locations

Question 35

What infection is Propionobacterium acnes associated with?

Answer 35

Acne | Prosthetic Devices

Question 36

What is Peptostreptococcus associated with?

Answer 36

Often found among mixed infections like brain, intraabdominal, lung

Question 37

What is the hallmark of B. fragilis infection?

Answer 37

Abscess formation – Inflammatory response to infection – Encapsulated “pus”

Question 38

What are the main virulence factors of B. fragilis?

Answer 38

- Polysaccharide Capsule | - O2 Tolerance

Question 39

What is the function of the B. fragilis toxin?

Answer 39

Nothing. It is defective.

Question 40

How does B. fragilis infection normally occur?

Answer 40

Stool infection of a wound

Question 41

What are the characteristics of Prevotella?

Answer 41

– Non-motile – Non-encapsulated – Strict anaerobe

Question 42

What infections do P. bivia and P. disiens cause?

Answer 42

Female genital tract infections

Question 43

What infections does P. melaninogenica cause?

Answer 43

Oralcavity, urogenital, GI tract

Question 44

What is the best antibiotic for Fusobacterium infection?

Answer 44

Metronidazole

Question 45

What is the best antibiotic for Peptostreptococcus infection?

Answer 45

Penicillin

Question 46

What infections does Porphyromonas cause?

Answer 46

Mixed or single oral, periodontal infections

Question 47

What infections does Fusobacterium nucleatum cause?

Answer 47

* aspiration pneumonia, lung abscess, empyema, chronic otitis media, sinusitis, brain abscess * liver abscess

Question 48

What is the main virulence factor of Fusobacterium?

Answer 48

High virulence toxin

Question 49

What infections does Fusobacterium necrophorum cause?

Answer 49

* Lemierre’s syndrome/ post anginal sepsis | * widespread metastatic infection