Micro 5 - Other Gram Positive Bacteria Flashcards
(37 cards)
What type of bacteria is Corynebacterium diptheriae?
G(+) rod.
What is the mechanism of the Diphtheria toxin?
ADP ribosylator of EF-2 (elongation factor).
Which bacterial toxin have a similar toxin that inactivates EF-2?
Diphtheria toxin and Exotoxin A (pseudomonas).
What does Diphtheria toxin target?
Damages nerve cells and heart cells. Causes pseudomembranouse pharyngitis (if scraped, bleeds profusely): spreads to respiratory system, causing the “bull neck” diphtheria.
How is diagnosis of Diphtheria made?
Growth of G(+) rods on culture and proof of toxin production.
What is the treatment for Diphtheria?
Antibiotic (Erythromycin, penicillin) to kill the bacteria and antitoxin to inactive the toxin. And vaccine because natural infection does not induce immunity.
Which G(+) rods produces spores? Which G(-) produces spores?
Bacillus spp. And Clostridium spp. Coxiella burnetii is the G(-) that produces spores and causes Q fever.
What is the mechanism of tetanospasmin (tetanus toxin)?
Blocks release of inhibitory neurotransmitters, increasing firing of motor neurons. Causes trismus (lockjaw).
What is the mechanism of action of botulinum toxin?
Produces heat labile toxin that inhibits ACh at NMJ. Causes flaccid paralysis. Honey may contain spores.
What is the mechanism of alpha toxin produced by Clostridium perfringens?
Alpha toxin is a phospholipase that causes gas gangrene and myonecrosis.
What does Clostridium difficile cause?
Pseudomembranous colitis.
What are the 4 main types of Clostridium?
Clostridium tetani, botulinum, difficile, perfringens.
Which G(+) rod that produces spores is anaerobic? Which one is aerobic?
Anaerobic are the clostridium species, and the aerobic are bacillus.
What are the three components of the anthrax toxin?
Edema factor, lethal factor, protective antigen.
What are the three different presentations of anthrax? Which one is the most common?
Cutaneous, Inhalation and GI. Cutaneous is the most common.
What is the clinical presentation of Cutaneous anthrax?
Occurs when spores enters skin. Starts with a small papule that evolves into a large, painless ulcer with central necrosis. There can be significant area of edema around the ulcer due to toxin production.
What is the pathophysiology of inhalation anthrax?
AKA Wool sorter’s disease, aerosolized spores enter the respiratory system and are phagocytosed in alveoli then taken to mediastinal lymph nodes. Bacteria can then enter the bloodstream causing widespread infection, sepsis and death.
What do we see in CXR in inhalation of anthrax?
Mediastinal widening.
What are three obligate anaerobes?
Clostridium tetani, actinomyces, and bacteroides.
What two antibiotics are effective for anaerobes?
Metronidazole, Clindamycin.
What is the pathophysiology of Listeria monocytogenes infection?
It enters thru the GI tract and penetrates intestinal mucosa. It is then taken up by monocytes, and reside there (they are facultative intracellular organisms). If it infects a pregnant woman, it can cross the placenta, resulting in fetal loss or newborn sepsis.
In what foods do we find Listeria monocytogenes?
Unpasteurized milk and cheese, and contaminated deli meats.
What three bacteria are especially known for newborn sepsis?
Group B strep, E.coli, Listeria.
What bacteria has branching filaments and can be stained with an acid fast Stain?
Nocardia.
