Disease, Transmission & S. aureus

Question 1

define infection

Answer 1

pathogens overcome body’s natural resistance, multiply and become established in the body

Question 2

when do we see signs and symptoms?

Answer 2

when the body mounts a response to an infection

Question 3

define infectious

Answer 3

able to be transmitted from one host to another

Question 4

define pathogenesis

Answer 4

the harm that the pathogen is doing to the host

Question 5

what is the pathogenesis of Vibrio cholera and HIV?

Answer 5

V. cholera: destroys epithelium of sm. intestine

HIV: destroys helper T-cells

Question 6

define pathogenicity

Answer 6

pathogen’s ability to cause disease in the host

Question 7

define virulence

Answer 7

measure of pathogenicity

Question 8

define virulence factor

Answer 8

what the pathogen uses to cause harm in the host

Question 9

what can virulence factors be?

Answer 9

enzyme, molecule, toxin, particular structure

Question 10

define infectious dose

Answer 10

number of microbes needed to establish an infection in the host

Question 11

a lower infectious dose for a microbe is (easier/harder) to transmit

Answer 11

easier

Question 12

infectious dose for enterohemorrhagic type of E. coli

infectious dose for V. cholera

Answer 12

10 cells

1000 to 1 million cells

Question 13

6 modes of transmission

Answer 13

direct contact

indirect contact

droplet

airborne

contaminated food & water

vectorborne

Question 14

fecal-oral is a type of _______ transmission

Answer 14

direct contact

Question 15

what is a fomite and what type of transmission is it involved with?

Answer 15

inanimate object that could harbor microbes

indirect contact

Question 16

what is direct transmission?

Answer 16

skin & mucous membrane contact between hosts

touching, kissing, sex

Question 17

what is indirect contact transmission?

Answer 17

transfer of microbes via inanimate objects

Question 18

what is droplet transmission?

Answer 18

droplets (coughing, sneezing) settle onto a surface, or could be inhaled while in midair

Question 19

what is airborne transmission?

Answer 19

very small droplets dry out in the air and become suspended there

Question 20

what is cross-contamination?

Answer 20

pathogens from one food source transferred to another

Question 21

raw poultry meat contains which bacteria?

Answer 21

Salmonella sp.

Question 22

what is vectorborne transmission?

what usually serves as a vector?

Answer 22

Living organism carries pathogen & transmits it to host

arthropod - mosquito, fly, tick, flea

Question 23

what is a biological vector?

Answer 23

arthropod plays vital role in pathogen’s life cycle

Question 24

What is S. aureus’ Gram and shape?

Answer 24

Gram +

coccus

Question 25

what can a staph infection cause? (6)

Answer 25

food poisoning wound infections toxic shock syndrome impetigo scalded skin syndrome folliculitis

Question 26

how can staph be transmitted?

Answer 26

direct indirect droplet

Question 27

2 main varieties of MRSA

Answer 27

community associated healthcare/hospital associated

Question 28

staph favors the ______ mucosa

Answer 28

nasal

Question 29

\_\_% of people are colonized with staph, and \_\_\_\_\_\_% with MRSA

Answer 29

40% 10-15%

Question 30

what are bacteremia and septicemia

Answer 30

bacteremia - bacteria grow in blood septicemia - bacteria and/or their toxins reach blood

Question 31

staph's 7 virulence factors

Answer 31

capsule coagulase clumping factor enterotoxin ALPHA toxin leukocidin exfoliatin

Question 32

what does a capsule do for staph?

Answer 32

helps in evading phagocytosis

Question 33

what is the function of coagulase?

Answer 33

activates prothrombin causes blood to clot protects bacteria from immune cells evading phagocytosis

Question 34

what is the function of clumping factor?

Answer 34

allows bacteria to attach to surfaces and clots

Question 35

which virulence factors make it easy for staph to infect humans?

Answer 35

coagulase clumping factor

Question 36

what does enterotoxin cause?

Answer 36

if ingested - food poisoning in blood - toxic shock syndrome

Question 37

what are signs and symptoms of TSS

Answer 37

Diarrhea, ill feeling, headache, fever, nausea, vomiting, organ failure, death Hallmark: very red eyes, mouth, throat, skin

Question 38

TSS used to be caused by... but is now mainly caused by...

Answer 38

tampons left in too long packed wounds that aren't changed

Question 39

what is the function of ALPHA toxin?

Answer 39

pokes holes in plasma membranes

Question 40

which virulence factor of staph causes necrosis? what is necrosis?

Answer 40

ALPHA toxin tissue death

Question 41

what is the function of leukocidin?

Answer 41

kills WBCs, especially neutrophils

Question 42

what is the function of exfoliatin? what does it cause?

Answer 42

separates layers of epidermis scalded skin syndrome