TB And Non TB Flashcards
Name three types of mycobacteria
Leprae
Tuberculosis complex
Non tuberculosis mycobacteria
Mycobacterial characteristics
+ rods
Nonmotile
No spores
No capsule
Obligate aerobe
Very slow growing (or not at all)
Describe acid fastness
Holds on to RED phenolic dye
Result of MYCOLIC ACIDS
- long chain fatty acids
- most of cell weight
How is M. Tuberculosis spread?
Person to person
Aerosolized droplet nuclei from cough
-can remain in air for hours
What happens to TB once inhaled?
Infects, grows
Ingested by MACS
Stay alive
-> form Granuloma
What are the two types of TB manifestations?
LATENT
- asymptomatic
- non-infectious
ACTIVE
- symptomatic
- infectious
Name some clinical syndromes of TB
GHON lesion
- seen on x-Ray
- healed tissue
CAVITIES
- hole in lung
- contains lots of bacteria
- very infectious
MILIARY
-throughout lung
How does HIV relate to TB?
HIV greatly enhances ability of TB to take hold
TB controlled by CD4 cells
HIV depletes CD4 cells
Latent -> active
Active -> more deadly
How would you diagnose active TB?
ACID FAST BACILLUS smear
- same day results
- LIMITED sensitivity
- LIMITED specificity
CULTURE
- MORE sensitive
- MORE time (2-3 weeks)
- MORE labor
- MORE costs
NUCLEIC ACID AMP
-use tb specific probe
How would you treat active TB?
4 RIPE for 2 months
INH/RIF for 2 months
Beware of resistance
How would you diagnose latent TB?
Tuberculin Skin Test
- delayed hypersensitivity IV
- uses PPD
- 2-10 weeks after initial infection
- measure INDURATION
- cross reaction
INTERFERON GAMMA RELEASE ASSAY (IGRA)
- blood assay
- look for IFN response
How would you prevent TB?
Quick diagnosis and isolation of infected patients
Continuously test high risk individuals (health workers)
Vaccine?
Is there a TB vaccine?
why yes
Uses myco Bovis (cow TB)
Great for kids, ok for adults
Can cross react with PPD but not IGRA
How are mycobacteria doing in the world?
Tuberculosis is pretty popular around the world
Leprae is falling globally
How is Leprae transmitted?
Probably respiratory? Maybe breaks in the skin?
Only infects humans (and armadillos)
NEEDS A HOST
What medium can you use to culture Leprae?
NONE
Can’t be cultured foo
What are the two forms of Hansen’s Disease?
TUBERCULOID
LEPROMATOUS
Main features of tuberculoid Hansen’s?
noncaseating granulomas
Few bacteria
Smear lesions negative
Flat, red, lesions
Positive skin test
Good prognosis
Main features of Lepromatous Hansen’s?
Few granulomas
Lots of bacteria
Positive AFB smears
See large, thick nodules
Antibody mediated
Negative skin test
Bad prognosis
How do you diagnose Hansen’s?
Gross appearance
Histological exam
Acid fast stains
How are nontuberculous mycobacteria transmitte?
NOT person to person
Soil, water, animals
Clinical significance Of NTM?
Often contaminant
Can colonize w/o disease
Opportunistic
Who does NTM hit?
Children
Chronic Lung disease and smokers
Older, tall, thin women?
