Anaerobic Bacteria (lecture) Flashcards
Strict anaerobic (lack catalase and superoxide dismutase), G +, spore forming rod - what is the genus?
Clostridia
Bacteroides has both cat and superoxide dismutase
Actinomyces is Gram ______ (+/-) ________ (aerobic/anaerobic), ________ (non-sporeforming/spore forming), ________ (cocci, rod).
G +, anaerobic, non-sporeforming, rod
Propionibacterium is ________ (aerobic/anaerobic), ________ (non-sporeforming/spore forming), ________ (cocci, rod), Gram (+/-).
anaerobic, non-sporeforming, rod, G +
Baceroides and Fusobacterium are ________ (aerobic/anaerobic), ________ (non-sporeforming/spore forming), ________ (cocci, rod), Gram (+/-).
anaerobic, non-sporeforming, rod, G -
What is the only anaerobe bacteria mentioned in class that is catalase and superoxide dismutase positive (is not a strict anaerobe)?
Bacteroides
What is the virulence factor of Clostridia?
Toxin formation
Remember that botulism must be preformed
What is the most common source of anaerobic infections?
One’s own flora
How is polymicrobial infection of both anaerobic and aerobic infection of a wound beneficial to anaerobes?
Aerobes may use up all of the O2, resulting in an ideal environment for anaerobes
What is the most common source of anaerobic infections above the waist?
Dental carries
What is the most common source of anaerobic infections below the waist?
GI/GU flora
What are the three most commonly used antibiotics used for above the waist anaerobic infections?
Metronidazole (interferes with nucleic acid production)
Augmentin (amox/clav acid)
Clindamycin (target 50s subunit)
What bacteria genus is most associated with gas gangrene?
Clostridia
Clostridia is confirmed. On gram stain, it is found to have a polar clearing (looks like a tennis racket). What is the likely species? What if it were to have a central clearing (as in a propeller)?
tetani is tennis racket like
botulinum is propeller like
What characteristic of Clostridium contributes most to its ability to cause gas gangrene?
The high metabolic rate causes gas formation.
Diabetic with severe gas gangrene and blue and black discoloration of his foot. What is the most significant virulence factor of the likely causal organism?
Lecithinase kills cells and lyses RBCs.
What is the term used when a bacteria goes from a spore to its active form?
germination
Man with poor dentition presents with significant submandibular swelling and purulent discharge that has grainy contents coming out of the swollen area. What is expected on gram stain?
Actinomyces: Long, G + rods that form chains
What is the most common causal organism of acne and its staining pattern?
Propionibacterium: Anaerobic, G + rods (does NOT grow in BILE vs. bacteroides)
Note: also common in PROSTHETIC related infections
Woman with poor dentition present with abdominal pain. One of the organisms identified on staining show G - rods that are very long and skinny (looks like strings). What is the likely organism identified?
Fusobacterium nucleatum
Abdominal abscess is found to have G - rods that are aerotolerant and catalase +. What is the main virulence factor of the likely causative organism? What consideration must be made with regard to Abx prescription?
Bacteroides: Its polysaccharide capsule helps it avoid phagocytosis. It makes B-lactamase (no PCNs)
