23 - Bacterial Pathogens causing Human Disease

Question 1

on average which is more severe: upper or lower resp infection?

Answer 1

lower

Question 2

upper resp infection, gram + cocci with large capsule, found in sore throat in kids, humans only known reservoir, resp droplet transmission

Answer 2

streptococcus pyogenes

Question 3

strep throat is ____, and there is no immunity to reinfection but still need treat with antibiotics

Answer 3

self limiting

Question 4

strep throat symptoms + skin rash caused by certain strains that produce erythrogenic exotoxin

Answer 4

scarlet fever

Question 5

erythrogenic exotoxin is carried via ___ throughout body and damages ____

Answer 5

blood; small blood vessels (fever, rash, strawberry tongue)

Question 6

what cause glomerulonephritis?

Answer 6

immune complexes accumulate in glomeruli of kineys, occurs in recovery stage of untreated strep

Question 7

autoimmune disease where Ab formed against strep cross react with heart 3-4 wks after self limited strep

Answer 7

rheumatic fever

Question 8

destructive tissue infection caused by various bacterial species including strep pyogenes (produce enzymes that degrade connective tissue, invade to deeper muscle tissues)

Answer 8

necrotizing fascitis

Question 9

necrotizing fascitis only spread by:

Answer 9

entry into skin via cuts

Question 10

why take throat swab?

Answer 10

look for hemolytic colonies on blood agar

Question 11

infections of lower resp tract caused by variety of bacteria species

Answer 11

pneumonia

Question 12

types of pneumonia?

Answer 12

lobar (entire section of lungs), bronchial (patches around bronch tubes)

Question 13

pneumonia leads to:

Answer 13

inflammation of lungs (chills, high fever, bloody sputum) and filling of air spaces with fluids

Question 14

important virulence factors in pneumonia

Answer 14

bacterial capsules

Question 15

lower resp infection, slow growing, acid fast, humans only known reservoir, lacks most of usual virulence factors in other bacteria

Answer 15

mycobacterium tuberculosis

Question 16

all disease in TB due to ____

Answer 16

host immune response

Question 17

2 forms of TB

Answer 17

primary (first time) and secondary

Question 18

mech of primary?

Answer 18

airborn/droplet transmission, TB survives and multiplies in phagocytic cells, break open, TH cells activated and stim. macrophage after 3 weeks, which kill M.Tb or create Ghon complex/tubercle to prevent further spread

Question 19

in ___% of primary cases, tubercles heal by _____

Answer 19

95; fibrosis + calcification

Question 20

what is secondary TB?

Answer 20

reactivation of dormant tubercles –>activate TH results in delayed hypersensitivity–>can occur years after primary infection

Question 21

how diagnose TB?

Answer 21

acid fast stain of sputum, lab culture of TB from sputum, tuberculin skin test

Question 22

gold standard for diagnosis?

Answer 22

lab culture (but slowww)

Question 23

what is vaccine for TB/

Answer 23

BCG (attenuated, live mycobacterium bovis)

Question 24

before 1950s , TB treated with ___, now use ____

Answer 24

long term care in sanatorium; anti-mycobacterial drugs (isoniazid, rifampin) for 6-9 mths daily treatment

Question 25

probs of antimycobacterial drugs?

Answer 25

compliance and resistance

Question 26

infectious dose of TB is:

Answer 26

10 organisms!