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15 Cards in this Set
- Front
- Back
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What are Mycoplasma?
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The Mycoplasmataceae are the tiniest free living organisms capable of self replication. They are smaller than some large viruses.
They lacl a peptidoglycan cell wall. Their cell membrane is packed with sterols(like cholesterol). They can contort into a broad range of shapes. they are not considered rods or cocci. |
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Are antibiotics effective against them?
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They lack a cell wall (penicillin, cephalosporin), as well as the effectiveness of the antiribosomal antibiotics erythromycin and tetracycline.
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List 2 pathogenic species of Mycoplasma.
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1. M. pneumoniae
2. Ureaplasma urealyticum |
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What is M. pneumoniae?
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It causes a mild, self limited bronchitis and pneumonia. It is the #1 cause of bacterial pneumonia in teenagers and adolescentsa.
It attaches to respiratory epithelial cells with the help of protein P1(adhesin virulence factor). |
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What are some of the symptoms?
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After a 2-3 week incubation period, there is a gradual onset of fever, sore throat malaise and a dry hacking cough. it is commonly called walking pneumonia, because patients really dont feel ill.
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List 4 diagnostic tests for M. pneumoniae.
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1. Cold agglutinins test
2. Complement fixation 3. Sputum culture 4. Mycoplasma DNA probe |
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What is the Cold agglutinins test?
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Certain antigens present on human RBCs are identical to antigens of the M. pneumoniae membrane glycolipids. Antibodies to these M. pneumoniae antigens cross react with human RBC antigens and agglutinate the RBCs at 4C. These antibodies are thus called cold agglutinins.
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How soon do these antibodies develop?
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They develo by the first or second week of the M. pneumoniae infection, and will decline in number over several months.
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Can this test be performed at the bedside?
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Yes. Put the patients blood in a non clotting tube. After placing this tube on ice, the blood will clump together if the patient has developed the cold agglutinin antibodies.
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Regarding the above bedside procedure, what will happen if you lift the tube out of the ice?
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The blood will unclump as it warms in the palm of your hand.
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Can M. pneumoniae and U. urealyticum be grown on artificial medium?
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Yes. These media however, must be rich in cholesterol and contain nucleic acids(purines and pyrimadines).
after 2-3 weeks, they will assume a fried egg appearance. |
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Why is Ureaplasma, not called Mycoplasma?
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Ureaplasma loves to thrive in urine, and produces urease to break down urea(urealytic). It is referred sometimes as T-strain Mycoplasma, as it produces Tiny colonies when cultured.
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Is U. urealyticum found naturally?
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It is part of the normal flora in 60% of healthy sexually active women and commonly infects the lower urinary tract, causing urethritis.
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List 2 other bacteria that cause urethritis.
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1. Neisseria gonorrhea
2. Chlamydia trachomatis. |
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How is U. urealyticum identified?
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It is identified by its ability to metabolize urea into ammonia and CO2.
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