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Flashcards in Anaerobic Bacteria Deck (13):

Why are most anaerobic infections actually polymicrobial (mixed)?

Strict anaerobes cannot use O2 because they do not have catalase (except bacteriodes) or superoxide dismutase and are unable to break down H2O2 to prevent damage from superoxide


What are the types of anaerobic infections?

Toxin mediated where the preformed toxin is ingested (Botulism)
Toxin formed in Vivo (C. Diff, C. Perfringes, C. Tetani)


What changes in physiology lead to deep tissue anaerobe infections?

Deep infections with endogenous anaerobes most commonly occur due to decreased vascular support and perfusion. On all mucocutaenous surfaces anaerobes predominate. Low O2 tension, warmth, moisture and substrate allow for opportunistic infection.


What source of anaerobes is most important to consider in the treatment of war wounds?

Exogenous sources like dirt, spores, or foreign bodies


What are the most likely sites of anaerobic infection?

Oral cavity, skin, GI system, GU tract


What does foul smelling pus in an infection indicate?

Anaerobic infection


How do you treat "above the waist" anaerobic infections?

Penicillin G, they should be susceptible to most Abx


What are the major species of Clostridia that cause human disease?

C. Difficile
C. Botulinum
C. Perfringens
C. Tetani

C. Perfringens is the most common cause of invasive clostridial infection
All are gram positive toxin forming rods


What is the virulence factor in invasive clostridial infection?

Lecithinase: a phospholipid that kills cells and hemolyzes RBCs in vitro and in vivo leading to dead tissue without the presence of PMNs


What organism should you think of when you hear "lumpy jaw" and sulfur granules?

Actinomyces: a gram positive, non spore forming rod.
Macrocolonies under microscope sometimes look like grains of sand. The abcess gives a granular feel and therefore a lumpy jaw.
Actinomyces is associate with poor oral hygeine or after invasive dental surgery.


What bacteria causes Acne?

Proprionobacterium: an anaerobic gram positive rod that does not form spores.


What do you know about Bacteriodes?

Facultative anaerobe
Gram negative rod
Causes mixed infection
Antiphagocytic due to it's polysaccharide capsule
May cause liver abscesses
Produces beta-lactamases (don't use penicillin)


What do you know about Fusobacterium?

Anaerobic, non-spore forming, gram negative rod
Long and filamentous on microscopy
Plays a role in periodontal disease
Linked to colorectal cancer