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18 Cards in this Set
- Front
- Back
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Acid fast organisms
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Mycobacterium spp, Nocardia spp
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Cell wall variants
1. no cell wall 2. defective cell wall 3. poorly staining cell wall |
1. mycoplasma, ureaplasma
2. chlamydia 3. rickettsia, ehrlichia, legionella |
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Spirochetes
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Treponema, Borrelia, Leptospira
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Mycobacterium
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-waxy cell walls
-retain various dyes after destaining with acid alcohols (acid fast) -long chain fatty acids in cell wall: barrier to nutrients -cause chronic, slowly progressive infections |
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Mycobacterium tuberculosis
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-tuberculosis: chronic respiratory infection which may spread via blood to kidneys, CNS, skin etc.
-seen in malnutritioned and immunosupressed people in US -transmission occurs person to person -usually lag between infection and disease -not all infected idividuals develop clinical disease -identify with PPD skin test checking Th cells |
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Mycobacteria other than tuberculosis (MOTT)
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-opportunistic pathogens
-most common are M. avium complex (N) and M. kansasii (P): produce chronic respiratory and disseminated infections in immunosuppressed pts -M fortuitum (R): causes post surgical infections |
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different categories of MOTT based on growth characteristics
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1. scotochromogens: always pigmented
2. photochromogens: pigmented after exposure to light 3. non-photochromogens: not pigmented 4. rapidy growing: grow in a few days in vitro |
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Mycoplasm pneumoniae
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-common cause of respiratory infections (pharyngitis, bronchitis, pneumonia)
-no cell wall (can't treat w/ B-lactam antibiotics) -Tx with macrolides (erythromycin) or fluoroquinolones (levofloxacin) |
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Normal flora of female genital tract
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Ureaplasma urealyticum and Mycoplasma hominis
-occasionally produce infections in that area and in newborns |
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Chlamydia
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-cell wall defective organisms
-weird life cycle -B-lactam antibiotics don't work, because there is little PG in cell wall -Tx: doxycline, quinolones, azithromycin |
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Chlamydia life cycle
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-can't make ATP so they're obligate intracellular pathogens
-infectious stage: elementary body that is metabolically inert -once inside cells, convert to reticulate body and start replicate -eventually convert bac to EB, lyse cell, and are released |
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Chlamydia trachomatis
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-one of the most common STDs in the US
-urethritis and cervicitis -often asymptomatic in females -may progress to PID, infertility, ectopic pregnancy -blindness (trachoma) in poor hygiene nations |
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Chlamydia pneumoniae
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-common cause of respiratory infections (bronchitis, pneumonia)
-diagnosis requires cell culture (rarely done) or culture independent methods (DFA, ELISA, PCR) |
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Rickettsiaceae
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-obligate intracellular parasites
-R. rickettsii: rocky mountain spotted fever -Coxiella burnetti: Q fever -Rickettsia spp: typhus -ehrlichosis -stain poorly with gram stain -transmitted to humans via arthropod vector -diagnosed serologically |
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Rocky Mountain Spotted Fever
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caused by R. rickettsii
-not seen in rocky mts. -transmitted to humans via ticks -infectes endothelial cells producing characteristic rash -may spread to lungs |
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Legionella
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Pulmonary pathogens
-many species, many serotypes -L. pneumonia serotype 1 is most common -survive in aquatic environments (hot water tanks, cooling towers, etc) -infections develop as a result of environmental exposure (occur in clusters) |
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Treponema pallidum
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-spirochete
-causes syphilis (transmitted sexually) -hard, painless chancre at site of inoculum that can prduce skin and mucosal lesions (secondary) or neurosyphilis and cardiovascular syphillis (tertiary) -diagnosed by serology (RPR and MHA-TP) -TX: penicillin or cephalosporin |
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Borrelia burdorferi
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-Lyme disease (zoonotic infection transmitted via ticks)
-produces lesion (erythema chronicum migrans) at site of inoculum that spreads to joints and CNS |
