micro 5 Flashcards
charact of mycobacteria
aerobic
non spore
immotile
gram positive
what does mycobacteria have in its cell wall
hydrophobic material (mycolic acid)
hydrophobicity gives mycobacteria what charac
slow grower
chronic disease
resist drugs
resist decolorization
mycobacteria classified into
m.tb complex
m.leprae
non tuberculous mycobacteria (NTM) : stypical mycobacteria
MAC : m.avium and m.intracellular what group
type 3 slow grower
classification of NTM
Slow grower and rapid grower on lowenstein jensen (LJ)
slow grower classified according to ability to produce yellow carotenoid pigment what are the types
type 1 : photochromogens (only in light)
type 2 : scotochromogens (dark and light)
type 3 : nonchromogens
progression of TB depend on
balance between virulence and immune system
virulence factors of mycobacteria
catabolism of oxidants
prevent phagolysosome fusion
immune system factors against TB
IL-12 : TH1 diffrentiation that secrete interferon gamma
IFN gamma: enhance phagolysosome fusion
TNF alpha: reactive nitrogen species (RNS)
In response to TB infection what type of sensitivity develops
delayed type HS (DTH)
epitheloid cells that enhance secreting
langhans giant cells enhanced phagocytic activity
two possible outcomes when bacilli attacked by immune system
immediate eradication
development of specific immunity
immediate eradication what happens
bacteria eliminated by innate immune system (macrophages)
body not sensitized to bacteria
specific immunity what happens
DTH in regional LN (ghon focus)
ghon focus and LN its called ghon complex or primary complex this is called primary TB
Outcomes of primary tb
progressive primary tb
latent tb
progressive primary tb
host immune response is weak leading to active disease
pneumonia like ( middle and lower lobe with LAP hilar and pleural effusion)
segmental tb
hemorragic
obstruction
bacteremia
latent tb
host immune response is strong to keep microbe in dormant
when there is a resume in microbial activity what is it called
post primary or secondary
secondary tb
reactivation of old strain or reinfection with new one
features of secondary tb / open tb
in apex
fibrosis and cavitation
aspergilloma
distant spread in secondary TB occurs through
tracheobronchial tree
pulmonary vein : systemic miliary tb
pulmonary artery ; ;localized pulmonary miliary tb
lymphatic system ; diffuse pulmonary miliary tb
immunodiagnosis of tb
tuberculin skin test
in vitro interferon gamma assay (IGRA) : QUANTIFERON TB (GOLD)
Microscopy for tb
carbol fuchsin stain : zn and kinyoun under brightfield
auramine rhodamine ; florescent microscope
PCR for tb
increased sensitivity and specificity
predicts MDR
culture of tb
early morning sample for 3 consecutive days
decontamination by an alkali (2% NaOH)
medium used : LJ medium or middlebrook and needs 4 weeks
liquid medium needs 2 weeks and for MODS
FIRST LINE TB DRUG
Isoniazid
rifampin
ethambutol
pyrazinamide
second line tb
p-aminosalicylic acid
cycloserine
aminoglycoside
capreomycin
MDR TB
To isoniazid and rifampin
XDR TB
MDR TB with resistance to one injectable second line and 1 floroquinolone
treatment course phases
initiation and continuation
immunoprophylaxis using what
BCG (m.bovis)
immunoprophylaxis decrease risk of
tb meningitis and disseminated disease in children
pulmonary TB in adults
BCG vaccine contraindicated in
immunocompromised
MAC causes
disseminated disease in AIDS
how is mac transmitted
ingestion
mac causes what in immunocompetent
tb like cavitation in middle or elderly man with history of lun disease
bronchiectasis, middle lobe or lingular infiltrate in non smoker elderly women
solitary pulmonary nodule
chemoprophylaxis for mac in HIV patients with CD4 below 50 by
macrolide
rapidly growing mycobacteria (RGM) organisms
M. fortuitum
M.chelonae
M.abscessus
RGM can be found on body surfaces without causing disease but can also cause chronic diseases with multiple recurrences
yes
RGM can acuse
pulmonary infection without cavitation and multilobar or iatrogenic or opportunistic infec
RGM treated by
clarithromycin
what drug is an arabinogalactan syn inhib
ethambutol
what drug is mycolic acid syn inhib
isoniazid
ethionamide and prothionamide
what is the MOA of pyrazinamide
distrubts cell emmbrane eneergy function
what is the MOA of rifampin
inhibitor on DNA dependent RNA pol
what is a peptidoglycan syn inhib
cycloserine
