L20_Anaerobic Bacteria Flashcards
What do Obligate anaerobes use pyruvate for?
As an electron acceptor to re-oxidize coenzymes used in glycolysis
What are the two common sources of anaerobic infection?
- Normal Flora
2. Soil(spores)
What is a tell tale sign of anaerobic bacteria?
Abscess that fills will bacteria and dead neutrophils, swells, becomes painful, PUS
What are two common routes that anaerobes form the soil enter the body?
- A puncture wound
2. Vacuum-packed foods
Why shouldn’t you let a baby eat honey?
There can be spores in the honey (botulism) that the undeveloped immune system of the baby will not kill. The spores can germinate within the gut and fuck your kid up!
How can gas chromatography help identify anaerobes?
It can help identify the organic acids or alcohols being produced by the anaerobes fermentation pathways (sometimes you can run pus directly)
What are three laboratory tests that can be used to help identify anaerobes?
Gram Stain, Chemical testing, GC
Is there a lot of pressure for Anaerobes to develop antibiotic resistance? Why?
No. Because they are usually environmentally sourced.
How is an abscess from an anaerobic infection generally treated?
Surgery - drain and debride, followed by antibiotics.
How is a toxigenic disease caused by anaerobes generally treated?
Antitoxin administration. In many cases no antibiotic is needed because the is no active culture of the bug, just the exotoxin (i.e. botulism)
Name an antibiotic specific for anaerobic bacteria.
metronidazole
What are the four major genera of anaerobic bacteria. How do each Gram stain, what is the shape of all of them, which form spores.
Clostridium (Gram + and spore forming), Bacteroides (Gram -), Prevotella (Gram -), Actinomyces (Gram +) All are Rod shaped
What general category do Bacteroides and Prevotella fall under?
GNAB or ANGB (Gram negative anaerobic bacteria)
What do all infectious environmental anaerobes have in common?
Spore forming capabilities
How do all anaerobes cause disease
Exotoxins
What type of waste products products are produced by anaerobic bacteria?
organic acids, alcohols, or even solvents
Name a couple enzymes that obligate anaerobes lack which cause them to be intolerant to oxygen.
Catalase, oxygen dimutase
What type of precautions must be taken with a liquid culture of anaerobes to ensure proper growth?
liquid media filled all the way to the top, tightly stoppered, treated with reducing agents, not shaken
How can an anaerobic plate be streaked and grown?
In a culture jar.
What type of toxins does tetanus and botulism release?
neurotoxins
What type of virulences factors does gas gangrene and abscess formation depend on?
tissue-degrading enzymes
What is the best way to prevent tetanus?
Tetanus Vaccines (DTap)
Describe how tetanus toxin works
Large subunit carries small subunit to presynaptic motor nueron. The large subunit opens a pore in the neuron and inserts the small subunit. The small subunit travels by retrograde axonal transport back towards central nervous system (2-14 days). The small subunit acts as a protease and cleave synaptobrevin which causes loss of central inhibitory activity on motor and autonomic neurons.
What bacteria causes pseudomembranous colitis?
C. difficile
What can cause pseumembranous colitis?
recent course of antibiotics or cancer chemo that suppress other normal flora and allow C. difficile to overgrow.
How does C. Difficile effect the host?
Mainly exotoxin B disrupts sytoskeleton by depolymerizing actin and killing surrounding cells.
What are some options to treat pseudomembranous colitis?
Withdraw initial antibiotic that cause imbalance. Administer anaerobic specific antibiotics like metronidazole or vancomycin.
