Intracellular Bacteria

Question 1

3 main intracellular bacteria

Answer 1

mycobacterium, legionella, chlamydia

Question 2

required immune response for intracellular pathogens

Answer 2

need cell mediated to clear infection, antibodies not helpful

antibiotics must penetrate host cells

Question 3

describe legionella bacteria and its infection

Answer 3

facultative intracellular, G-, causes acute pneumonia and not transmitted person to person

Question 4

risk factors for legionella infection

Answer 4

it is opportunistic pathogen- inhalation of contaminated water

old age, smoking, COPD, intubation, immunosuppression

Question 5

pontiac fever cause and illness

Answer 5

flu like, but upper respiratory w/o pneumonia, most recover w/o rx

Question 6

legionella location in humans

Answer 6

grow and reproduce in macrophages- legionella containing vacuoles

Question 7

describe the immune response to legionella infection

Answer 7

infected macrophages release cytokines, recruit monocytes/PMNs and induce inflammation, TNF-alpha also produced and Th1 response also helps clear infection

Question 8

dx and rx for legionella

Answer 8

culture on charcoal yeast extract agar

macrolides for rx- good at penetrating host cells

Question 9

describe chlamydia bacterium and infection

Answer 9

obligate intracellular, G-, causes walking pneumonia

Question 10

spread of chlamydia

Answer 10

person to person via respiratory droplets

Question 11

rx of chlamydia pneumoniae

Answer 11

doxycycline- accumulates in host cells

Question 12

differentiate the 3 “bodies” of chlamydia lifecycle

Answer 12

elementary bodies are infectious but inert, become reticulate bodies which are active but non-infectious (block fusion w/ lysosome inside macrophage)

inclusion bodies are the chlamydia-containing vacuoles

Question 13

zoonotic host of chlamydia psittaci

Answer 13

birds, usually parrots or chickens

Question 14

presentation of psittacosis

Answer 14

ranges from asymptomatic to severe systemic w/ pneumonia

usually upper respiratory illness but can have lobar or interstitial infiltrates

Question 15

dx of psittacosis

Answer 15

culture, serology, NAAT

Question 16

dx of chlamydia pneumoniae

Answer 16

tissue culture cells

Question 17

chlamydia pneumo is similar to what infection

Answer 17

mycoplasma

Question 18

which intracellular bacteria are obligate human pathogens? which arent?

Answer 18

MTb and Chlamydia pneumo are, chlamydia psittaci (birds) and legionella (ameobas) are not