Objectives 11-13

Question 1

Define herd immunity

Answer 1

when a high proportion of a population has immunity to an infectious disease, the entire population is protected, including the susceptible members

Question 2

what is nosocomial infection?

Answer 2

a hospital acquired infection

i.e. infections that weren’t present on admission

Question 3

How does a high population density in hospitals contribute to nosocomial infections?

Answer 3

• crowding in rooms/wards/waiting areas
• staff and visitor numbers
• increases risk of cross-infection

Question 4

How do infectious patients in hospitals contribute to nosocomial infections?

Answer 4

• they represent reservoirs of infection

Question 5

How are vulnerable patients hospitals affected by nosocomial infections?

Answer 5

• they are more suseptible to infection
• burns and trauma patients
• premature neonates
• AIDS, IIDS patients

Question 6

How does patient to patient contact in hospitals contribute to nosocomial infections?

Answer 6

• regular traffic of hospital staff from patient to patient increases chance of pathogen transfer

Question 7

How do routine procedures in hospitals contribute to nosocomial infections?

Answer 7

• carry risk of infection

- i.e catheterization, injections, taking biopsies

Question 8

How does surgical procedures in hospitals contribute to nosocomial infections?

Answer 8

• expose normally sterile tissue
• stress of surgery mat diminish patient resistance to infection
• the more longer and complex the procedure –> the greater the risk

Question 9

How do antibiotics contribute to nosocomial infections?

Answer 9

• encourages emergence of antibiotic resistant strains (superbugs)
• interfere with normal flora leading to opportunistic infections
• false confidence leading to poor aseptic technique

Question 10

How do immunosupressive drugs contribute to nosocomial infections?

Answer 10

• compromises body defenses against infection

- increase vulnerability to infection

Question 11

what are the 4 categories of nosocomial infections?

Answer 11

1. UTIs
2. Surgical wound infections
3. respiratory tract infections
4. blood, skin and other infections

Question 12

What percentage of nosocomial infections do UTIs make up?

Answer 12

40-50%

Question 13

what is the main cause of UTIs? Why?

Answer 13

urinary catheterization

• contaminated catheter
• poor cleaning of insertion site
• movement of organisms from leaky connections

Question 14

What percentage of nosocomial infections do surgical wounds cause?

Answer 14

15-25%

Question 15

How do surgical wounds cause infection?

Answer 15

• exposure of normally sterile tissue to pathogenic organisms

Question 16

What percentage of nosocomial infections do respiratory tract infections cause?

Answer 16

15-30%

Question 17

how are respiratory tract infections usually caused in a hospital setting?

Answer 17

related to use of respiratory tract devices that administer air/o2/medication to the lungs

Question 18

What percentage of nosocomial infections do blood, skin and other infections cause?

Answer 18

10-20%

- usually bacteremia and speticemia are associated with IV catheterisation

Question 19

50% of bacterial infections come from which 4 bacteria?

Answer 19

• Escherichia coli
• Staphylococcus aureus
• Streptococcus pyogenes
• Pseudomonas aeruginosa