Term
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Definition
| corynebacterium, mycobacterium, nocardia (branching). gram pos, non-motile, cat pos, rod-like to filamentous morphology |
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Term
| mycobacterium staining, growth, cell wall |
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Definition
| acid fast, slow growers (7-8 weeks before calling culture neg), very lipid natured cell wall- resistance to drying acid and alkaline conditions (why TB can often lie dormant) |
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Term
| Mycobacterium leperae found where, 2 forms, treatment, what countries, incubation, affect on body |
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Definition
| can't be cultured but can grow in the foot pads of armadillos. causes leprosy/Hansen's disease (disease of rural poor). 2 forms- tuberculoid form (intense cell mediated response, very few bacteria in tissues, noncaesating granulomas) and leperoid form (no cellular immune response, lots of bacteria present, skin lesions-face, elbows, buttocks, knees, wrists, saddle nose). treat w rifampin or dapsone 6-12 months. it is an obligate intracellular parasite. seen in India, Brazil, Bangladesh, Indonesia, still seen in US too. incubation of 3-5 years, can cause nerve damage (loss of peripheral sensation), muscle atrophy, contractions |
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Term
| Mycobacterium tuberculosis |
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Definition
| causative agent of TB, can disrupt the phagosomal membranes of alveolar macrophages (bypass these macrophages that clean up cellular debris in lungs and instead divide inside them), then cytokine release and later immune response |
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Term
| Mycobacterium host response/pathophys |
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Definition
| host responds w cell-mediated immune response- delayed hypersensitivity -> granulomatous lesions/tubercle w core of rounded macrophages surrounded by outer giant cells w fibrous outer layer -> cheesy necrosis due to drying phagocytes releasing toxins (caseating granuloma) -> calcification |
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Term
| Mycobacterium TB spread, contraction, incidence |
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Definition
| spread by airborne droplets which must penetrate deep into the respiratory tract, increased development of MDR TB since AIDS epidemic. Inc in TB in late 80s/early 90s bc of AIDS epidemic but drop in cases since |
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Term
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Definition
| clinically- prolonged productive cough, acid fast stain and culture of sputum, can do PPD, if high index of suspicion sputum MTB PCR |
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Term
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Definition
| prevention- treatment and quarantine of cases, aggressive antibiotic therapy (isoniazid, rifampin, ethambutol, pyrazinamide and others) |
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Term
| what causes delayed type hypersensitivity in TB? |
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Definition
| giant macrophage cell granuloma |
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Term
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Definition
| can liquify tissues and spread throughout lungs (miliary disease), or to brain, joints, kidneys, multiple organs |
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Term
| what determines pathogenicity of mycobacteria |
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Definition
| exposure (coughing), infection (organism taken in and multiples in macrophages), disease (organism prevents macrophage from fusing w lysosomes and acidification, organism doesn't get destroyed, is able to get into lymphatic system and spread to remote sites) |
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Term
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Definition
| advancing age, alcoholism, HIV infection, malnutrition, anything that decreases your immune status, immunosuppressive drugs, chronic steroids, leukemia, lymphoma |
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Term
| how MTB gets coughed into environment |
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Definition
| granuloma ruptures into the airway and all the bacteria are released and get coughed up |
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Term
| classic signs and symptoms of TB reactivation |
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Definition
| fever, night sweats, weight loss |
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Term
| other organism that can cause tuberculosis |
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Definition
| Mycobacterium bovis- get from unpasturized milk (carried by cows) can get chronic disease (weight loss, fever, night sweats) |
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Term
| 2 types of TB and symptoms |
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Definition
Pulmonary TB- chronic cough, hemoptysis, blood-tinged sputum, cavitary or infiltrate lesions in the lungs
Extrapulmonary TB- other organs and sites, lymph nodes, pleural space, genitourinary bones, adrenal glands. more common in pts who are immunocompromised (HIV/AIDS) |
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Term
| groups that are particularly susceptible to mortality from TB |
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Definition
| groups w/o a long history of urbanization- Native Americans, Eskimos |
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Term
| miliary TB symptoms and CXR, sputum and AFB smears |
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Definition
| may not have a cough, bc it has spread- hepatomegaly, splenomegaly, lymphadenophathy. CXR has snowstorm pattern, sputum and AFB smears are usually neg |
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Term
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Definition
| Tuberculin skin test, PPD, use purified protein derivative injected intradermally, look for classic delayed hypersensitivity response- induration after 48 hrs, may see some redness but not interested in that. can cross react w ppl who have had BCG vaccine or ppl who are infected w an atypical mycobacterium. can get false neg from anything that dec's immune response (malnutrition, other infections, immunosuppressive drugs), degree of pos or neg depends on pt, can be 5mm to 10 mm |
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Term
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Definition
| interferon release whole blood assay, detects latent and active TB (doesn't distinguish), pts w MTB have lymphs that recognize this Ag and this recognition is detected bc interferon is produced, 2 Ag's- ESAT-6 and CFP-10, uses enzyme or fluorescent marker, pos if one or both Ags are pos. prob bc there is an intermittent inability to detect infection |
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Term
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Definition
| may see fluid, granulomatous lesion |
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Term
| big difference between quantiferon gold and PPD |
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Definition
| quantiferon gold has a pos control, PPD does not |
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Term
| gold standard for diagnosis of acute TB |
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Definition
| grow on Lowenstein-Jensen Media |
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Term
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Definition
| detect radioactive materials before you see the colony, nucleic acid probes (species differentiation), DNA probes + PCR |
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Term
| Acid Fast staining for mycobacterium |
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Definition
| presumptive positive, other organisms can stain pos too, confirm with culture |
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Term
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Definition
| Idea is that you get exposed to M. bovis so then you will be able to mount an immune response against MTB. Variable effectiveness, not used in US |
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Term
| Protocol for pts in hospital w AFB pos sputums |
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Definition
| place on respiratory isolation, private negative pressure rooms |
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Term
| Mycobacterium avium intracellular complex |
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Definition
| MAC/MAI, M.avium and M. intracellulare, cause disseminated and GI disease, seen in HIV pts, like to grow in bone marrow, prophylax for this in HIV pts if CD4 count gets really low |
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Term
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Definition
| pulmonary infections similar to tuberculosis |
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Term
| M. abscessus and M. fortuitum |
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Definition
– “Rapid-growers”
– Cause postoperative wound infections and venous access line infections |
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Term
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Definition
| causes soft tissue infections following contact with fish tanks, fish, or salt water |
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