Bacterial Infections of Soft Tissue II: Anaerobes

Question 1

What is the Gram stain, Reservoir and Disease caused by C. tetani?

Answer 1

+ rod, soil, tetanus

Question 2

Gram stain, Reservoir, Disease caused by C. botulinum?

Answer 2

+ rod, soil, poorly vacuum-sealed containers, botulism

Question 3

Gram stain, Reservoir, Disease caused by C. perfringens

Answer 3

+ rod, soil (common), normal gut flora, gas gangrene/food poisoning

Question 4

Gram stain, Reservoir, Disease caused by C. difficle

Answer 4

+ rod; normal gut flora; pseudomembranous colitis

Question 5

Gram stain, Reservoir, Disease caused by B. fragilis

Answer 5

• rod; Normal flora of colon; abscess, peritonitis, necrotizing fasciitis, bacteremia, usually below diaphragm

Question 6

Gram stain, Reservoir, Disease caused by P. melaninogenica and B. corrodens

Answer 6

• rods; Normal flora of mouth; Abcess usually above diaphragm

Question 7

Gram stain, Reservoir, Disease caused by A. israelii

Answer 7

+ rods in long filaments; normal flora of mouth; Hard, nontender swelling w/ pus containing sulfur granules

Question 8

C. tetani virulence factors

Answer 8

Protease exotoxin tetanospasmin blocks release of neuromediators

Question 9

C. botulinum virulence factors

Answer 9

Protease exotoxin botulinum neurotoxin blocks release of acetylcholine, C2 toxin depolymerizes actin

Question 10

C. perfringens virulence factors

Answer 10

Alpha toxin (lechithinase), collagenase, hyaluronidase, sialidase, epsilon and theta toxins (which form pores in cell membranes), iota toxin (depolymerizes actin) Note: all break down tissue, Enterotoxin: in small bowel causes diarrhea

Question 11

B. fragilis virulence factors

Answer 11

Capsule, hyaluronidase, collagenase, phospholipase, antibiotic resistance

Question 12

C. difficile virulence factors? Mechanism of action?

Answer 12

Exotoxins A and B; Glucosyltransferases that glucosylate Rho GTPase, leading to depol of actin and a major inflamm response in the gut

Question 13

P. melaninogenica and B. corrodens virulence factors

Answer 13

Hyaluronidase, collagenease, phospholipase

Question 14

Of all these fun bugs, which has a vaccine?

Answer 14

C. Tetani

Question 15

Important procedures when making a Dx of anaerobic organism infection

Answer 15

Sample must be obtained from a normally-sterile source to eliminate confusion with normal flora, Store sample under anaerobic conditions

Question 16

Methods used to make Dx?

Answer 16

Anaerobic culture, Gram stain, Gas chromatography

Question 17

When would you suspect an anaerobic infection?

Answer 17

Deep-tissue trauma, accidents, cancer, surgery, immunosuppression, IV drug use

Question 18

What are the two types of bugs that are Gram + rods?

Answer 18

Clostridia and actinomyces

Question 19

What bugs are part of your normal flora? Which bug is part of the environment and normal flora?

Answer 19

C. diff, Bacterioides, Prevotella, Actinomyces; C. perfringens

Question 20

Describe the action of the proteases of C. botulinum and C. tetani. Describe their clinical presentation. Tx for both infections?

Answer 20

Both neurotoxins have the same activity but opposite clinical effects because of the nerves affected (tetanospasmin -> spasms; botulinum toxin -> flaccid); Primarily antitoxin

Question 21

Lethal condition associated with C. perfringens

Answer 21

Gas gangrene