Gram Indeterminate Bacteria Flashcards
acid fast bacilli
mycobacterium tuberculosis
why is mycobacterium tuberculosis acid fast?
retains stain d/t high mycolic acid content in cells
virculence factors: mycobacterium tuberculosis
cord factor
activates macrophages
sulfatides
cord factor
serpintine cord appearance in virulent M. tuberculosis
what are the affects of macrophage activation by M. tuberculosis?
granuloma formation
release of TNF-a
sulfatides
surface glycolipids that inhibit phagolysosome fusion
enable survival and intracellular replication in macrophages
How is M. tuberculosis transmitted?
inhaled respiratory droplet
TB patients should be placed in ____________ for containment
negative pressure isolation
TB replicates in
macrophages
Activation of macrophages by TB induces __________ by cord factor
phagocytosis
TB survives due to failure of _________________ due to sulfatides
phagolysosome fusion
TB forms granulomas with ___________ necrosis
caseous
TB forms caseous granulomas composed of
activated macrophages and Th1 cells
**Langhan’s cells may also be seen
Granulomas form to
contain the bacterial infection
Risk factors for TB
immunocompromised, prisoners, immigrants, healthcare workers
Symptoms: TB
weight loss, fever, night sweats, cough, hemoptysis
Where is the Gohn complex seen in primary tuberculosis?
lower lung
Gohn focus
granulomatous focal lesion seen in TB
TB replicates in
alveolar macrophages
Primary TB may be eliminated but bacteria often survive in
large caseating granulomas
Gohn complex
Gohn focus + lymph node
Gohn complex is seen as ________ on CXR
focal lesion and hilar adenopathy
Primary TB: inhaled droplets of bacteria are phagocytosed by
alveolar macrophages
Latent TB will present with a [positive/negative] PPD skin test
positive
latent TB is contained in
granulomas with calcification
Patients with latent TB are __________ and have ________ CXR
asymptomatic; unremarkable
Secondary tuberculosis is seen in ___________ patients
immunocompromised
elderly, AIDS, steroid use, biologic drugs
Secondary tuberculosis is due to
failure of granulomas to contain bacterial spread
secondary TB is seen on CXR as
cavitary lesions in upper lung
miliary TB
dissemination and seeding of TB causing little focuses resembling millet seed
what is it called when TB spreads to vertebrae?
Potts disease
milliary TB can cause
Potts, meningitis, pericarditis, mediastinitis, skin lesions, hepatic lesions
laboratory tests TB
PCR, PPD skin test, IGRA
PPD
purified protein derivative
The TB PPD skin test tests for
prior exposure and cell mediated immunity
immunocompromised patients can present with a _______ PPD skin test
false negative
positive PPD skin test diameter for patients with no risk factors
> 15 mm
positive PPD skin test diameter for patients with risk factors
> 10 mm
positive PPD skin test diameter for immunocompromised patients or recent contact
> 5 mm
positive PPD skin tests require a _____ to confirm
CXR
IGRA
measures amount of IFN-gamma released by T cells when exposed to antigens
IGRA tests for
prior exposure and cell mediated immunity
IGRA is ________ over PPD
preferred
Bacille Calmmette Geurin vaccination can cause false positive
Treatment for TB
RIPE
1st line: Rifampin, Isoniazid
no cell wall
mycoplasma pneumoniae
grown on eaton agar
mycoplasma pneumoniae
cell wall contains cholesterol
mycoplasma pneumoniae
transmission: mycoplasma pneumoniae
droplet
occurs in young (<30) individuals living in close contact
mycoplasma pneumoniae
CXR looks worse than patient presentation would suggest
mycoplasma pneumoniae
symptoms: mycoplasma pneumoniae
slow onset: fever, headache, nonproductive cough
CXR: mycoplasma pneumoniae
pathy/diffuse interstitial infiltrate
atypical pneumonia
IgM antibodies agglutinate RBCs under cold temperature
mycoplasma pneumoniae
causes hemolytic anemia
mycoplasma pneumoniae
treatment: mycoplasma pneumoniae
macrolides, fluoroquinolone
is penicillin effective against mycoplasma pneumoniae?
no, no cell wall
