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Mycobacteria characteristics:
- Obligate Aerobes
- Slender rod shaped
- Non-motile
- Non-sporulating
- Ubiquitous organism that can be found in humans and animals
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Unique features of Mycoacteria
- Acid Fast (Ziehl-Neelsen)
- Cell wall lipid: mycolic acid
- Resist acids, alkalis and germacide antibiotics
- Pathogens = rough colonies
- Grow and divide slowly
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Acid fast bacteria stain:
pink
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non-acid fast bacteria stain:
blue
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Term for Mycobacterium Tuberculum in acid fast smears is:
Acid fast Bacilli
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Easier method (than acid fast staining) to screen for Mycobacteria:
Auramine stain
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Auramine stained mycobacteria appear:
Glowing yellow rods
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Infections of mycobacteria can often be seen where?
Inside Macrophages in the lymph nodes
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Mycobacteria infect what type of immune cell
macrophages
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Cord Factor characteristics:
- Glycolipid
- Inhibits migration of PMNs
- Small quantiites are lethal in lab animals
- abundant in virulent strains
- absesnse= non-virulent
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Cord factor absesnse =
non-virulent strain
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Cord factor is a:
Glycolipid cell wall component
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Virulence factors for Mycobacteria
- Clumpy in water/ether
- Cord factor
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Gram stain of Mycobacteria
Neither G+ or -
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Mycobacteria taxonomy is based on these characterisitics:
- Colony morphology
- Pigmentation
- Growth Rate
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Characteristics of Mycobacteria in Group I
- Photochromatic - only produce pigemented colonies in lighted conditions
- Slow growth (greater than one week)
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Example of Group I mycobacteria
Mycobacterium kansassi
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Mycobacterium kansassi pigmentation color
yellow orange colonies
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Yellow oragnge colonies of mycobacterium indicated the genus and species:
Mycobacterium kansassi
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Mycobacterium kansassi only produce pigment under what condition?
Presence of light
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Mycobacterium kansassi growth rate is:
slow, greater than one week
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Group II mycobacteria characteristics:
- Slow growth rate (greater than 1 week)
- Scotochromogenic - produce pigement in the absense of light
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Group II Mycobacteria example
Mycobacterium scrofulaceum - produces red orange colonies
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Mycobacterium scrofulaceum produces colonie that are colored:
red-orange
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red orange mycobacteria colonies indicate the species and genus of:
Mycobacterium scrofulaceum
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Mycobacterium scrofulaceum has a gorwth rate that is:
Slow, greater than one week
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Mycobacterium scrofulaceum is in Group:
II
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Mycobacterium kansassi is in the Group:
I
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Mycobacterium Group III characteristics:
- Slow growth rate (greater than 1 week)
- Non-pigmented
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Example of Group III Mycobacterium:
Mycobacterium avium-intracellulare
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What color are teh colonies of Mycobacterium avium-intracellulare
Buff colored
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Mycobacterium avium-intracellulare is a member of mycobacterium Group:
III
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Group IV Mycobacterium characteristics:
Fast growth rates
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An example of Mycobacterium Group IV is:
Mycobacterium Fortuitum-chelonae
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Mycobacterium Fortuitum-chelonae is a member of what mycobacterial Group:
IV
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Mycobacterium fortuitum-chelonae is what color:
Non-pigmented
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Mycobacterium fotuitum-chelonae has a growth rate of:
fast (less than one week)
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MOTT stands for:
Mycobacterium other than M. Tuberculosis
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MOTT is a classification of what type of mycobacterium?
Those other than M. tuberculosis
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Characteristics of the disease tuberculosis are:
- Found worldwide
- Communicable disease
- Spread by droplet nuclei
- Primary lesion-tubercle or lymph node lesion
- Primary complex
- Caseation/secondary lesion
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Tubercule foci are medically significant because they can:
harbour bacteria for years until teh host immune defenses are comprimised.
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Droplet nuclei are transmitted through the:
Air
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Droplet nuclei are created by
speaking, singing, coughing of infecetd individual
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Droplet nuclei are transferred by contact (true/false)
False
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Droplet Nuclei land where:
The Lungs
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Another term for Miliary tuberculosis is:
Disseminated tuberculosis
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Disseminated/Miliary tuberculosis is different from normal tuberculosis in that:
- The infection is not localized to the Lungs
- Many organs are effected
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Miliary/disseminated tuberculosis can result from:
Breaking of bacterial pockets into blood stream and traveling around the body.
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Previously exposed individuals (to M. Tuberculosis) develop what immune response:
Delayed type hypersensitivity
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What is the basis for TB skin tests
Delayed type hypersensitivity that develops after TB exposure.
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The immune response to TB is:
Cell mediated immune reaction or T cell response
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The Mantoux test is for:
TB
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The Mantoux test is administered where:
Intradermally
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The Mantoux skin test needs to incubate for:
48-72 hours
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After receiving a Mantoux test, an induration of 0-5mm indicates:
Negative for TB
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After receiving a Mantoux test, an induration of 5-9 mm indicates:
Indeterminate previous TB
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After receiving a Mantoux test, an induration of 10mm or more indicates:
Positive for TB
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A positive TB test can be determined by:
An induration of greater than 10mm
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An indeterminate TB test is determined by:
An induration of 5-9mm
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A negative TB test can be determined by:
An induration of 0-5mm
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A TB test is also called
A Mantoux test
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The Mantoux test divides the population into how many groups?
Two
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Downfalls of Mantoux TB test:
false positives due to allergic reaction
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The Mantoux test is performed by injecting:
PPD
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PPD stands for
Purified Protein Dervivative
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Flase positive of Mantoux test can be verified or dismissed using what other test?
Quantiferon Gold test
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Which test for Tb has the most specificity?
Quantiferon Gold test
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Quantiferon Gold test detects:
Release of IFN-g in whole blood when incubated with 2 synthetic peptides represnting proteins of TB
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A huge induration after a TB test indicates:
Allergic reaction
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After seeing a huge induration after a PPD TB test, you should perform what other test?
Quantiferon Gold test
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Which TB test detects INF-g:
Quantiferon Gold test
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Treatment of TB is:
Chemotherapy
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TB treatment regimen last how many months:
6
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Treatment of TB in the first 2 months is with:
isoniazid, rifampin, pyrazinamide
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At what point and for how long is a TB patient administered isoniazid, rifampin and pyrazinamide?
The first 2 months of treatment
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After the first two months these drugs are used to treat TB for 4 months:
isonazid and rifampin
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The two drugs that are used to treat TB for the first 6 months are:
isonazid and rifampin
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isonazid and rifampin are used to treat Tb during which treatment stages?
The first 6 months
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pyrazinamide is used to treat TB suring what treatment period?
The first 2 months
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Quantiferon Gold TB test is positive when
ESAT-6-nil or CFP-10-nil are greater than or equal to 0.35 IU/mL and 50% nil
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The majority of TB cases need treatment (true/flase)?
False
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The majority of TB cases are self limiting (true/false)
True
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Developing coutries are seeing an increase or decrease in TB infections?
Increase
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Most TB hosts know that they have been infected (True/Flase)
Flase
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Most common Mycobacterium (other than M. tuberculosis) to cause infection:
Mycobacterium avium-intracellulare
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Treatment issues with non-M. tuberculosis infections
Many are antibiotic resistant and so hard to treat.
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Mycobacterium infection often seen in HIV patients:
Mycobacterium avium-intracellulare
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Types of infections caused by non-M. tuberculosis mycobacterium:
pulmonary or disseminated
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Tuberculosis in Europe
HIV patients have developed resistant tuberculosis strains which have entered the population in Geneva
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Tuberculosis cases in the U.S. reached a peak of what number in 1992
+26000
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What year did Tuberculosis recently peak above 26,000 cases in the U.S.?
1992
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Tuberculosis cases are currently declining or increasing in the U.S.?
Decreasing
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U.S. TB cases are at about what number per year?
14000
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Mycobacterium Leprae is also known as:
Hansen's Disease
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Leprosy is a highly contagious disease (True/Flase)?
False
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How many cases of Leprosy are there worldwide?
15 million
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Aquisition of Leprosy requires:
Frequent and Prolonged conact
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Hansen's Disease is caused by:
Mycobacterium Leprae
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Mycobacterium Leprae causes what disease
Lesprosy or Hansen's Disease
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Mycobacterium Leprae resovoirs are:
- Mouse footpad
- 9 banded armadillo
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Characteristics of Tuburculoid Leprosy
Anaesthetic Macules with Hypopigmentation
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Two major forms of leprosy
Lepromatus and Tuberculoid
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The severe form of leprosy is called:
Lepromatous Leprosy
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Lepromatous Leprosy is characterized by:
Disfigurement and loss of periphreal nerve function and lepromas
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Lepromas are:
Granulomatous thickenings
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In leprosy the acid fast bacilli invade what parts of the body preferentially?
Cooler parts
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Leprosmas can be defined discretely as:
Diffuse skin infiltrations of bacterial nodules of varying size.
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What stain is used for mycobacteria?
•Acid-fast (Ziehl-Neelsen)
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What is unique about the cell wall of mycobacteria?
- thicker
- Hydrophobic
- Waxy
- Mycolic Acid/Mycolates
cell wall consists of the hydrophobic mycolate layer and a peptidoglycan layer held together by arabinogalactan (polysaccharide)
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What is cord factor?
- A virulence factor:
- Glycolipid
- Inhibits migration of PMN’s
- Small quantities lethal in lab animals
- Aundant in virulent strains
- Asence = non-virulent
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What are photochromogens? Example?
- When light is needed to produce colony pigments.
- e.g. Mycobacterium kansassi which turn yellow orange in light
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What is a primary lesion?
Changes in DNA due to mutagens. Manifests as a process of the pathological process (pustules/nodules)
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What is a Secondary lesion?
occurs due to the evolution of a disease or due to primary lesions (scales/scabs)
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What is PPD?
purified protein derivative
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What mycobacterium infects HIV patients at a high rate?
Mycobacterium avium-intracellare
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