RT5

Question 1

major contributors to pathogenesis of influenza virus

Answer 1

T cell response, interferon induction, desquamation of mucus secreting and ciliated cells

Question 2

what is antigenic shift

Answer 2

sudden rearrangement of the 8 genetic subunits which results in major changes of HA and NA genes and is responsible for pandemics/epidemics

Question 3

what is antigenic drift

Answer 3

gradual accumulation of point mutations in genes encoding HA and NA leading to gradual loss of stereospecificity of the Ag-Ab bond (most impo in HA because effect of neutralizing Ab is lost)

Question 4

antigenic shift and drift is seen in which influenza

Answer 4

antigenic drift is seen in all 3 (with C being less frequent)

antigenic shift is only seen in A

Question 5

how do you diagnose influenza

Answer 5

clinical diagnosis based on symptoms and laboratory diagnosis

Question 6

anti flu drugs

Answer 6

amantadine, rimantadine, zanamivir, oseltamvir (tamiflu)

Question 7

how does amantadine and rimantadine work

Answer 7

by inhibiting the uncoating of type A only since its target is the M2 protein

B and C do not have the M2 protein

Question 8

how does zanamivir and oseltamvir work

Answer 8

inhibits neuraminidase – hence forcing virus to bind to its own sialic acid and form useless clump

essentially virus will not be released from the cell in Type A and B only since C does not have NA

Question 9

what happens with constant use of antimicrobials to treat the flu

Answer 9

we start to build drug resistance

Question 10

do we build acquired immunity to the flu and is it effective

Answer 10

we do but it is weak because the antigen changes constantly

Question 11

which influenza has an animal reservoir

Answer 11

just A

Question 12

another name for subacute LRT infection

Answer 12

walking pneumonia, atypical pneumonia

Question 13

prokaryotes for subacute LRT infection

Answer 13

mycoplasma spp, chlamydia spp, legionella sp, miscellaneous viruses

Question 14

eukaryotes for subacute LRT infection

Answer 14

usually fungi: histoplasma sp, blastomyces sp, coccoididiodes sp, candida sp

Question 15

findings in primary atypical pneumonia

Answer 15

low grade lung infection that resolves around 18 days, a little fever but it only lasts a few days

Question 16

common cause of walking pneumonia/atypical pneumonia/subacute LRT infection

Answer 16

mycoplasma

Question 17

walking pneumonia with mycoplasma is common in what population

Answer 17

children greater than 5 years old - young adults

Question 18

clinical syndrome of streptococcus pneumonia

Answer 18

pneumonia, sinusitis, and otitis media

Question 19

describe strep pneumonia on a blood agar

Answer 19

• sensitive to optochin (P disk)
• does alpha hemolysis which involves a change in the redox potential of RBCs making it less red which is not as transparent as s. pyogenes that does beta hemolysis

Question 20

commonest cause of community acquired pneumonia

Answer 20

strep pneumonia

Question 21

what type of infection is strep pneumonia

Answer 21

it is both exogenous and endogenous
endogenous - it is within us to start with already
exogenous - if we pass ours to another human it becomes exogenous

Question 22

pathogenesis of strep pneumonia

Answer 22

capsule, IgA protease, pneumolysin, autolysin, transformation

TAPIC

Question 23

properties of pneumolysin

Answer 23

inhibits ciliated epithelial cell activity, cytotoxic for alveolar and endothelial cells, causes inflammation, decreases PMN effectiveness

Question 24

prevention of strep pneumonia

Answer 24

polyvalent capsular polysaccharide vaccine , 7-valent conjugated vaccine

Question 25

clinical syndrome of klebsiella pneumonia

Answer 25

bronchopneumonia and lung abscesses

Question 26

general features of klebsiella pneumonia

Answer 26

• non motile, gram neg bacillus with a large capsule that has smooth/mucoid appearance
• part of normal flora
• uses aerobactin and enterochelin to uptake iron from host

Question 27

pathogenesis of klebsiella pneumonia

Answer 27

it is gram neg so –> release of endotoxin –> necrotizing of lung tissue

Question 28

diagnosis of klebsiella pneumonia

Answer 28

sputum will have red currant jelly appearance

Question 29

clinical syndrome of legionella pneumophila and transmission

Answer 29

legionnaires disease (pneumonia)
pontiac fever

inhalation of contaminated aerosols (Rare)

Question 30

general features of legionella pneumophila

Answer 30

gram neg, motile, non spore forming, facultative intracellular (alveolar macs)

Question 31

pathogenesis of legionella

Answer 31

endotoxin release, proteases, but most important damage is due to host inflammatory response

Question 32

stain for legionella

Answer 32

its a gram neg bacteria but cannot be picked up by gram stains so must use methylamine

Question 33

common infection of pseudomonas

Answer 33

otitis externa: swimmer’s ear

Question 34

pseudomonas is dangerous in what population

Answer 34

persons with structural defects in body defenses like burn victims, cystic fibrosis

Question 35

pseudomonas on blood agar

Answer 35

it is non hemolytic but produces mucoid colonies

Question 36

clinical syndrome of pseudomonas and cystic fibrosis

Answer 36

necrotizing bronchial pneumonia

Question 37

just know permanent highly drug resistant infections are the rule for pseudomonas and cystic fibrosis

Answer 37

OK

Question 38

clinical syndrome of mycobacterium tuberculosis

Answer 38

tuberculosis

Question 39

general features of mycobacterium tuberculosis

Answer 39

aerobic, acid fast, bacillus which grows in long, parallel chain called cords

Question 40

structure of mycobacterium tuberculosis

Answer 40

PG which is rich in mycolic acid which makes bacteria grow slowly, resist detergent, and is hydrophobic

LAM (lipoarabinomannan) is equivalent to O antigen on LPS in that it induces cytokine release, suppresses T cell proliferation, and inhibits activation of macrophages by IFNgamma

Question 41

transmission of tuberculosis

Answer 41

inhalation of aerosols

Question 42

resistance to TB is dependent on

Answer 42

subset of CD4+ helper T cells that produce α- interferon

so people with AIDs are more susceptible because they have a low CD4+ T cells