Intracellular Bacteria Flashcards
extracellular pathogens replicate where
- outside of the host
intracellular pathogens replicate where
- inside host cells
obligate intracellular pathogen that replicates in vacuoles
- chlamydia pneumoniae
facultative intracellular pathogen that replicates in vacuoles
- legionella pneumophila
what do antibiotics of intracellular pathogens have to do in order to reach the site of infection
- penetrate host cells
are antibodies helpful with intracellular pathogens
- no
what is required to control and clear infection of intracellular pathogens
- cell-mediated immunity
classification of legionella pneumophila
- facultative intracellular
- gram negative bacterium
what does legionella pneumophila cause
- acute pneumonia
is legionella pneumophila an obligate or opportunistic pathogen
- opportunistic pathogen
risk factors of legionella pneumophila infection
- inhalation of contaminated water
- advanced age (50+)
- cigarette smoking
- COPD
- tracheal intubation
- immunosuppression
what other infection does legionella pneumophila also cause
what kind of condition is this
- Pontiac fever
- upper respiratory; no pneumonia
in extracellular environment legionella pneumophila lives within
- biofilms
- fresh-water amoeba
is legionella pneumophila viable
cultivable?
- is viable
- is not cultivable
in intracellular environment, legionella pneumophila grows and survives in
- legionella containing vacuoles in macrophages
legionella pneumophila - infected macrophages release _______ that recruit ___________ resulting in _________
- release cytokines
- recruit monocytes and neutrophils to the lungs
- result in inflammation
legionella pneumophila - what released by macrophages helps control the infection
- TNF alpha
legionella pneumophila - what response is produced by the antigen specific T cells to clear the infection
- TH1 cell mediated immune response
- involving IFN-gamma
legionella pneumophila - how to diagnose
- culture on buffered charcoal yeast extract agar
legionella pneumophila treatment
- macrolides (azithromycin)
chlamydia pneumoniae classification
- obligate intracellular
- gram negative
chlamydia pneumoniae causes what condition
- walking pneumonia
how is chlamydia pneumoniae spread
- person-person by respiratory droplets
chlamydia pneumoniae can lead to pneumonia as a result of
- chronic inflammatory response
chlamydia pneumoniae treatment
- doxycycline
life cycle of chlamydia species
- elementary bodies (GETTING CHLAMYDIA IN ELEMENTARY SCHOOL)
- reticulate bodies
what are elementary bodies of chlamydia species
- metabolically inert but infectious form
what are reticulate bodies of chlamydia species
- metabolically active but noninfectious
chlamydia species infect what inside the host
- macrophages and epithelial cells
chlamydia species how it survives in the host
- modifies phagosomal membrane to block fusion with lysosome
chlamydia species containing vacuole is called
- inclusion body
(chlamydia psittaci) psittacosis most often associated with
- birds
(chlamydia psittaci) psittacosis usual presentation is
- URI
(chlamydia psittaci) psittacosis radiographic findings include
- lobar or interstitial infiltration
(chlamydia psittaci) psittacosis laboratory tests include
- culture
- serology
- NAAT
what kind of growth medium do you use for TB
- lowenstein-jensen agar
what kind of growth medium do you use for C. pneumoniae
- tissue culture cells
Name the intracellular bacteria
Mycobacterium (facultative)
Legionella (facultative)
Chlamydia (obligate)
Examples of extracellular pathogens
Step. pneumo
Bordetella pertussis
H. influenzae
many (but not all) ______ pathogens are cultivable in vitro
extracellular
_________ intracellular can be grown in vitro without host cells
facultative
sexually transmitted strain of chlamydia
chalmydia trachomatis
Name the pathogens that replicate intracellular in specialized vacuoles
chlamydia pneumoniae (obligate) legionells pneumophila (facultative)
Are antibiotics useful against chlamydia pneumoniae and legionella?
no
cell-mediated immunity required to control and clear infection
all viruses are obligate ________ pathoens
intracellular
causes acute pneumonia
Legionella
causes legionnaire’s disease; spread through air conditioning
legionella
Biggest risk factor for L. pneumophilia disease
immunocompromised hosts
Is L. pneumophilia spread person-to-person?
NO - spread through inhalation of contaminated water
Pontiac fever is caused by
Legionella
What is Pontiac fever
flu-like illness in IMMUNOCOMPETENT hosts
most pts. recover without treatment in a week
In the environement, extracellular legionella are _____ but ______. They persist in _____
viable
not-cultivate
biofilms
grows within fresh-water amoeba
legionella
Diagnosing Legionella is difficult because
- bacteria not present in large numbers in sputum
- stain poorly
- clinical features not distinctive
Best method to diagnose legionella
culture the organism on “buffered charcoal-yeast extract agar”
takes 3-5 days
Do legionella infections result in increased cold agluttinins?
NO!!
no increase in cold agluttinins with legionella
chlamydia transmission
spread person-to-person (respiratory droplets)
C. penumoniae is related to
C. trachomatis (STD) and C. psittaci (zoonotic)
What infection is hard to distinguish from Mycoplasma pneumoniae infection?
chlamydia pneumoniae
Why is chlamydia pneumonia difficult to diagnose
lack of well-standardized tests
Psittacosis caused by
C. pisittaci
most often associated with psittacine birds (parrots)
outbreaks amongst poultry plant workers
Psittacosis infection
ranges from asymptomatic infection to severe systemic disease with pneumonia
upper respiratory illness
CXR: lobar or interstitial infiltrates
L. pneumonia is a gram - _______
rod
