Anaerobic Bacteria - LECTURE ONLY Flashcards Preview

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What are some important anaerobic non-spore forming gram positive rods?

Actinomyces and Propionibacterium


Actinomyces are known to be common causes of infection in what body area?

Cervico-facial (after dental surgery or POOR ORAL HYGIENE)
Also mentioned thoracic and abdominal areas (like old IUDs causing infection)


This bug is known to cause "teenage pizza face syndrome"

Propionibacterium! (species acnes)
May also cause infection of prostheses


What are some Anaerobic Gram negative non-spore-forming rods?

Focus on Bacteroides, Fusobacterium: others are Porphyromonas Prevotella, Tannerella


Bacteroids fragilis is a predominant organism in what parts of the human body?

In the human gut and female GU tract!


Why is bacteroides fragilis such a problem for us? (3 reasons here)

It tends to make internal abscesses
It also has a capsule which is anti-phagocytic
Makes B-lactamases!


In what substance can B. fragilis grow that can help us diagnose an infection by this bug?

Bile! Can help in lab diagnosis


Where can we find Fusobacterium nucleatum in the human body?

Common oral bug, often a cause of periodontal disease
Commonly recovered from different monomicrobial and mixed infections in humans and animals


What human disease is associated with Fusobacterium?

Human Colorectal Cancer
Note: Uncertain at this time, but even if it is not a CAUSE, it may be used in the future as a biomarker for possible cancer


When you hear anaerobic, gram positive rod that forms spores, this should pop in your head IMMEDIATELY (damn it)

Clostridium perfringens (or at least clostridium)


Why do we care that Clostridia make spores?

They are NOT killed by alcohol, must wash hands to get them off
Spores are known to get into traumatic wounds


What enzyme does C. perfringens make that helps it perform the stormy fermentation

Lecithinase, which is a phospholipase that kills cells and hemolyzes RBCs in vitro AND IN VIVO (very unusual to prove this)
Note: there are other virulence factors, but this was the only one she mentioned in lecture


What does lecithinase lead to in the human body?

Dead tissue! Causes significant muscle necrosis WITHOUT PMNs (will appear reddish blue to black)


What is stormy fermentation?

When C. perfringens is placed into a tube with some milk and culture media, the lecithinase will ferment the milk rapidly (Irish Car Bomb style) and makes gas, causing it to bubble (stormy aspect)


What is a common pathogenesis of C. perfringens? (How an infection comes about and progresses)

1) Traumatic wound is contaminated by dirt or in surgery
2) Spores germinate and organism multiplies under conditions of LOW OXIDATION REDUCTION POTENTIAL (they hit this point a few times)
3) Exotoxins are made (i.e. lecithinase)
4) Necrosis of tissue leading to deeper penetration


How rapidly does C. perfringens infection spread?

RAPIDLY, need to deal with this without much delay


Are anaerobic infections often mixed or single infections?

They are often mixed! For example, if there is some E. coli around, the E. coli can use up the oxygen so that the anaerobes may live and spread!


What are some other notable diseases caused by clostridia species? (6 listed here)

Botulism, tetanus, GAS GANGRENE, food poisoning, C. difficile associated disease (CDAD) (whatever that is), and (drum roll please) pseudomembranous colitis!


What is one common site for anaerobic infections (hint: I am thinking in the head here)

Sinuses! Close proximity to dentition (lots of anaerobes there) and O2 concentration can be reduced by obstruction (allergies, cold, etc)


What species causes an infection that often drains with grainy or sand like material? May also be referred to as "sulfur granules"

Actinomyces! This is a bit of a weirdo because it is often a cause of monospecies infections!