Module 1: Sources and Prevention of Infection

Question 1

what is an endogenous infection?

Answer 1

infection gained from our own microbiota, common

Question 2

what is an exogenous infection?

Answer 2

infection gained from another’s microbiota

Question 3

what are fomites?

Answer 3

surfaces that can carry infectious organisms eg glass, door handles

Question 4

what are zoonosis diseases?

Answer 4

infectious diseases that can be transmitted from animals to humans

Question 5

what are some characteristics of the bacterial zoonotic infection Camplobacteriosis?

Answer 5

• acute onset of cramping, nausea, watery diarrhoea

- either stool containing blood or very watery

Question 6

what are the four main virulence factors of Campylobacter bacteria?

Answer 6

• production of toxins that cause diarrhoea

- high mobility allows them to break through mucus layer of the gut

Question 7

what does the cholera-like enterotoxin released from Campylobacter bacteria result in?

Answer 7

causes an overproduction of cAMP, leading to the efflux of sodium from intestinal cells, leading to watery diarrhoea

Question 8

what does the cytolethal distending toxin released from Campylobacter bacteria result in?

Answer 8

produces DNase which eats DNA to cause cell death and leads to bloody diarrhoea

Question 9

what do dermatophytes result in?

Answer 9

fungal infection that targets keratin stores in the human body (nails, hair, upper skin)

Question 10

what is giardia?

Answer 10

intestinal protozoan parasite that can cause serious health issues

Question 11

what are the two forms giardia can grow in?

Answer 11

• trophozoite

- cyst

Question 12

how many giardia cysts are required to cause infection in a normal gut compared to an immunocompromised gut?

Answer 12

10-25 cysts, compared to 1-2 in immunocompromised

Question 13

what is one significant effect giardia has on the intestinal epithelium?

Answer 13

blunts epithelial villi to reduce absorption leading to malabsorption and malnutrition

Question 14

what are environmental pathogens?

Answer 14

organisms hat spend most their life outside of a host, but will infect a host if it meets it (opportunistic)

Question 15

what kind of infection is Pseudomonas aeuruginosa?

Answer 15

bacterial

Question 16

what are the virulance factors of Pseudomonas aeuruginosa?

Answer 16

• biofilms
• phagocyte invasion
• invasins
• toxins

Question 17

what bacteria can cause dermonecrosis in burn wounds, corneal damage in the eye and lung damage?

Answer 17

Pseudomonas aeuruginosa

Question 18

how can you tell if you have Pseudomonas aeuruginosa infection?

Answer 18

• blue pus in agar
• fruity odour
• beta hemolysis

Question 19

how to treat a Pseudomonas aeuruginosa infection?

Answer 19

combination of broad antibacterial drugs

Question 20

what kind of infection is Aspergillus?

Answer 20

fungal

Question 21

what causes a Aspergillus infection?

Answer 21

the inhalation of spores leading to respiratory infections

Question 22

what is Aspergillosis disease?

Answer 22

causes an allergy by the spores, causes bad skin reactions

Question 23

what is Aspergilloma disease?

Answer 23

a fungal ball grows in the lung

Question 24

what can Aspergillus do to your blood vessels?

Answer 24

cause them to erode

Question 25

how to treat Aspergilloma?

Answer 25

antifungals work 60% of the time, otherwise surgery

Question 26

how to treat Aspergillosis?

Answer 26

antifungals are ineffective, so surgery

Question 27

what kind of infection is Cryptosporidium?

Answer 27

parasite

Question 28

in mild cases, what can Cryptosporidium cause?

Answer 28

watery diarrhoea, abdominal pain and vomiting that lasts 2 weeks

Question 29

in immunocompromised people, what can Cryptosporidium cause?

Answer 29

chronic diarrhoea for months to years, rapid dehydration, malnutrition, imbalances, death

Question 30

how do TNFa and prostglandins cause diarrhoea in a Cryptosporidium infection?

Answer 30

increasing the intestinal permeability causing water loss

Question 31

what are the 6 chains that make up the 'Chain of Infection'?

Answer 31

- infectious agent - reservoir - portal of exit - means of transmission - portal of entry - susceptible host

Question 32

what is an infectious agent?

Answer 32

any organism that is capable of infection

Question 33

what is a reservoir?

Answer 33

any place an infectious agent can survive

Question 34

can humans be a reservoir?

Answer 34

yes

Question 35

what is a portal of exit?

Answer 35

any means through which an infection can leave a reservoir

Question 36

what is a mode of transmission?

Answer 36

how an infectious agent can get from an infectious agent to a susceptible host

Question 37

what are the 4 main kinds of transmission?

Answer 37

contact, droplet, airborne or common vehicle

Question 38

what is the contact form of transmission?

Answer 38

either direct or indirect contact with the infectious agent

Question 39

what is the droplet form of transmission?

Answer 39

contact with a droplet that is large and travels a short distance of the infectious agent eg sneezing, coughing, talking

Question 40

what is the airborne form of transmission?

Answer 40

small particles of the infectious agent that can travel a long way to infect people

Question 41

what is the common vehicle form of transmission?

Answer 41

infection to a susceptible host through the use of a commonly used thing eg food, water, medications, blood donations

Question 42

what is the portal of entry?

Answer 42

how an infectious agent gets into the host

Question 43

what is a susceptible host

Answer 43

a person with lacking immunity or resistance of a potential pathogen

Question 44

why do young kids get infections?

Answer 44

that have immunological immaturity

Question 45

why do old people get infections?

Answer 45

they have immunosenscence

Question 46

what is a hospital acquired infection (HAI)?

Answer 46

infections people gain after admission to the hospital that they showed no evidence of having before admission

Question 47

what causes 40% of HAIs?

Answer 47

UTIs

Question 48

what is the main cause of hospital-gained UTIs?

Answer 48

catheters

Question 49

what causes surgical site infections?

Answer 49

infection in a surgical wound depending on the contamination level of the wound

Question 50

what kind of infection is ventilator-associated pneumonia an example of?

Answer 50

lower respiratory tract infection

Question 51

what causes most hospital-related bloodstream infections (BSI)?

Answer 51

a central venous catheter

Question 52

what is a community acquired infection?`

Answer 52

infections contracted outside a healthcare setting or diagnosed BEFORE 48 hours of admission

Question 53

what are the 3 main antimicrobial HAI and CAI?

Answer 53

- MRSA - ESBL - VRE