Bacterial Infections of Soft Tissue II: Anaerobes Flashcards
What is the Gram stain, Reservoir and Disease caused by C. tetani?
+ rod, soil, tetanus
Gram stain, Reservoir, Disease caused by C. botulinum?
+ rod, soil, poorly vacuum-sealed containers, botulism
Gram stain, Reservoir, Disease caused by C. perfringens
+ rod, soil (common), normal gut flora, gas gangrene/food poisoning
Gram stain, Reservoir, Disease caused by C. difficle
+ rod; normal gut flora; pseudomembranous colitis
Gram stain, Reservoir, Disease caused by B. fragilis
- rod; Normal flora of colon; abscess, peritonitis, necrotizing fasciitis, bacteremia, usually below diaphragm
Gram stain, Reservoir, Disease caused by P. melaninogenica and B. corrodens
- rods; Normal flora of mouth; Abcess usually above diaphragm
Gram stain, Reservoir, Disease caused by A. israelii
+ rods in long filaments; normal flora of mouth; Hard, nontender swelling w/ pus containing sulfur granules
C. tetani virulence factors
Protease exotoxin tetanospasmin blocks release of neuromediators
C. botulinum virulence factors
Protease exotoxin botulinum neurotoxin blocks release of acetylcholine, C2 toxin depolymerizes actin
C. perfringens virulence factors
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
B. fragilis virulence factors
Capsule, hyaluronidase, collagenase, phospholipase, antibiotic resistance
C. difficile virulence factors? Mechanism of action?
Exotoxins A and B; Glucosyltransferases that glucosylate Rho GTPase, leading to depol of actin and a major inflamm response in the gut
P. melaninogenica and B. corrodens virulence factors
Hyaluronidase, collagenease, phospholipase
Of all these fun bugs, which has a vaccine?
C. Tetani
Important procedures when making a Dx of anaerobic organism infection
Sample must be obtained from a normally-sterile source to eliminate confusion with normal flora, Store sample under anaerobic conditions
Methods used to make Dx?
Anaerobic culture, Gram stain, Gas chromatography
When would you suspect an anaerobic infection?
Deep-tissue trauma, accidents, cancer, surgery, immunosuppression, IV drug use
What are the two types of bugs that are Gram + rods?
Clostridia and actinomyces
What bugs are part of your normal flora? Which bug is part of the environment and normal flora?
C. diff, Bacterioides, Prevotella, Actinomyces; C. perfringens
Describe the action of the proteases of C. botulinum and C. tetani. Describe their clinical presentation. Tx for both infections?
Both neurotoxins have the same activity but opposite clinical effects because of the nerves affected (tetanospasmin -> spasms; botulinum toxin -> flaccid); Primarily antitoxin
Lethal condition associated with C. perfringens
Gas gangrene
