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47 Cards in this Set
- Front
- Back
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Morphology of Actinomycetales?
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G+, catalase positive, aerobic
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What is MAC? (attack)
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Mycobacterium avium intracellulare complex
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Where is MAC (attack) and Nocardia found?
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found in soil, water, decaying vegetation
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What are the 3 Acid fast bacteria with mycolic acid in their cell walls?
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Mycobacterium
Nocardia Corynebacterium |
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What are the two most common causes of infection by nontuberculous mycobacteria?
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MAC (attack)
Mycobacterium kansasii |
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What is the most common mycobacterial infection in AIDS pts?
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DMAC (daddy)
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What is the morphology of Actinomyces israelii?
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Anaerobic, G+, rod
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How do you differentiate between M. avium and M. intracellulare?
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DNA/RNA probes
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What is the morphology of M. avium and M. intracellulare?
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Gram Positive, Aerobic bacilli
Very acid fast |
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How fast does MAC grow?
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slow- 10-12 hour doubling time
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What aer the most common sources of MAC?
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cigarettes
Homes and hospitals |
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What temp does MAC grow best in?
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41C
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Where does MAC grow best?
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intraceullular growth
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What actually causes damage in MAC infections?
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host response to infection
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What is MAC resistant to?
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This is resistant to disinfection, NOT killed by chlorination
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How does MAC get in the body?
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inhalation or ingestion with food/water (hot water/showers)
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Does MAC get transmitted person to person?
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NO way jose
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Where is MAC distributed?
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worldwide !
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Who can get pulmonary MAC?
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everyone, NON HIV, HIV, immunosuppressed or not!
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What are MAC infections usually due to?
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primary/new infections
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How does the initial infection of MAC occur?
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This invades across the mucosa of the lungs or GI
Infects Resting macrophages spreads to submucosa and lymphatics |
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Where can MAC travel in AIDS pts?
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Liver, spleen, Bone, all over!
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What kind of MAC do immunocompetent people, with underlying lung disease- get?
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Pulmonary MAC
(fibrocavity disease, Fibronodular disease) |
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What is fibrocavity disease? who gets it? what part of lung?
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pulmonary MAC-
upper lobe disease in elderly male smokers. difficult to diagnose MAC recovered from sputum |
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What is fibronodular disease? who gets it? what part of lung?
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Fastidious elderly women +50 years. NON smoker. Who suppresses cough reflex
Middle/Lingular lobe Called Lady Windermeres syndrome |
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Why usually gets Lymphadenitis from MAC? where?
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kids 1-4 years old
usually involves unilateral cervical lymph nodes |
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Who usually gets DMAC? signs?
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AIDS pts with CD4 of less than 50 cells/micro liter
FUO, diarrhea, dyspena, upper right quadrant pain |
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Where does DMAC go in the body?
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this is not contained by granulomas, so it spreads to any organ or tissue.
causes enlarged and dysfunctional organs |
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is MAC/DMAC reportable?
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NO! unless its for AIDS pts
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How do you diagnose MAC?
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you must r/o fungals
presentation must be consistent with nontubercular mycobacterium Sterile site isolation is significant |
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How do you treat MAC?
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3 drug therapy (for both HIV and normal people)
Macrolides + ethanbutol and rifabutin |
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How long do you treat MAC for?
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1 year minimum or until 12 months after sputum is negative for MAC
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What kind of chemoprophylatcitc is given for HIV pts against MAC?
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clarithromycin, azithromycin
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Where is nocardia found in the world?
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worldwide, in the soil
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What is the morphology of nocardia?
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Acid Fast
Gram Positive Aerobic form Branched hyphae in tissues and cultures Catalase + |
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What is the colony morphology of nocardia?
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Dry to waxy
White to orange distinct growth patterns @ 35-45C |
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How do you identify nocardia?
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16s rRNA-based PCR
and Restriction Fragment Length Polymorphism |
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What are the virulence factors of nocardia?
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intracellular growth
disease comes from host response resistant to disinfection |
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Where does nocardia usually come from?
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exogenous infection from SOIL.
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Who usually gets nocardia?
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immunocompromised pts in hospitals
OR pts with underlying pulmonary conditions |
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Where is nocardia most prominent ?
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the dry warm climates of the southwest.
the dry dusty windy conditions facilitate the aerosolization |
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Are infections transmitted from person to person?
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NO they are not
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What are the 3 greatest risks for developing Nocardiosis?
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T-cell deficiencies
Chronic pulmonary diseases Bronchopulmonary infections |
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What are the signs of Nocardiosis?
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similar to pyogenic, but develops slowly
dyspnea, fever Cavitation/spread to pleura Dissemination into CNS or subcue tissues (brain abscess?) |
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How do you diagnose Nocardiosis?
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Gram stain (G+)
Acid fast stain (ziehl-neelsen stain) Decoloried by 1% H2SO4 means it is weak acid fast Culture Slow 1 week |
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What medium do you grow Nocardia on?
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Selective BCYE
or Modified Thayer-Martin |
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What is the drug of choice for Nocardiosis?
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Trimethoprim, sulfamthoxazole (TMP/SMX)
use 2-3 antibiotics for 3-6 weeks (IV if needed) |
