Infection Control

Question 1

What is a hospital-acquired infection (HAI)?

Answer 1

An infection developed in hospital which was not present or incubating at the time of admission

Question 2

What % of patients do admitted to hospital HAIs occur in?

Answer 2

~25%

Question 3

What are the most common sites of HAIs?

Answer 3

• Urinary tract
• Surgical wounds
• GI tract
• Any septicaemia

Question 4

How severe are HAIs?

Answer 4

Range, from mild to life-threatening

Question 5

Why do HAIs develop?

Answer 5

• Environment
• The host susceptible to infections
• Medical activites
• Change in microbiota of environment from the selection pressures of the hospital

Question 6

What aspects of the hospital environment can cause HAIs?

Answer 6

• Food supply
• Air supply
• Fomites
• Water supply

Question 7

What medical activities can cause HAIs?

Answer 7

• IV access
• Catheters
• Surgery

Question 8

Why may patients be more susceptible to infection?

Answer 8

• Increasing age
• Co-morbidities
• Chronic illness
• Poor physical states
• Neutropenia from chemotherapy
• T cell deficiencies

Question 9

Why may a patient have a T cell deficiency?

Answer 9

• HIV
• Transplant

Question 10

Are HAIs exogenous or endogenous?

Answer 10

Can be either

Question 11

What are endogenous microbiota?

Answer 11

The organisms that are part of the normal body microbiota, on the skin, GI tract etc.

Question 12

What are exogenous microbiota with respect to HAIs?

Answer 12

Microbes transferred from the hospital to the patient, by direct contact of;

• Contaminated hands
• Clothing
• Medical devices
• Airborne spread
• Contaminated food, water, or medicines

Question 13

What can exogenous microbiota be considered to be part of, with respect to HAIs?

Answer 13

The ecosystem of the hospital

Question 14

How can endogenously acquired HAIs be minimalised?

Answer 14

• By effective disinfection of the skin prior to surgery, especially in the heavily bacterial contaminated parts of the body.
• Appropriate use of perioperative antibiotics prophylaxis protocol.
• Smoking cessation and good nutrition.
• Any sutures or drains should be changed regularly

Question 15

How can operations be classified?

Answer 15

• Clean
• Contaminated
• Infected

Question 16

What does the classification of an operation as clean, contaminated, or infected depend on?

Answer 16

The area involved

Question 17

What does appropriate use of perioperative antibiotics prophylaxis protocal ensure?

Answer 17

That the antibiotic concentrations are highest at the surgical sites at maximal concentrations

Question 18

What can prolonged administration of antibiotics cause?

Answer 18

Increased risk of infection by resistant organisms

Question 19

How are exogenously acquired infections prevented?

Answer 19

Good clinical practice

Question 20

What methods are effective in preventing exogenously acquired infections?

Answer 20

• Hand-washing
• Alcohol gel hand rubs
• Sterile gloves

Question 21

Amongst who should good clinical practice with respect to preventing infection be encouraged?

Answer 21

Visitors

Question 22

How can the number of antibiotic resistant organisms be reduced?

Answer 22

• Environmental cleaning
• Judicious antibiotic prescribing

Question 23

How should the environment be cleaned to prevent antibiotic resistance?

Answer 23

• Sterilisation
• Disinfection
• Waste disposal

Question 24

What should happen to any individuals harbouring resistant organisms?

Answer 24

They should be isolated in single rooms

Question 25

What should happen to any individuals with air transmitted diseases?

Answer 25

They should be placed in a room with negative air pressure

Question 26

How should instruments be used to prevent exogenous infection?

Answer 26

Should be single use where applicable, yet any recycled should be sterilised correctly

Question 27

What should always be worn by healthcare workers to prevent exogenous infection?

Answer 27

Disposable gowns, gloves, and aprons

Question 28

What do poor standards of care predispose to?

Answer 28

Higher rates of infection

Question 29

What is meant by the endemic rate?

Answer 29

The normal rate of infection for a particular disease

Question 30

What is an epidemic?

Answer 30

A significant increase in the rate of infection above the endemic level

Question 31

What is an outbreak?

Answer 31

An epidemic due to a single cause

Question 32

How can investigation of an infection source, especially in an outbreak, be aided?

Answer 32

Typing

Question 33

What is the purpose of typing in infection investigation?

Answer 33

It determines if two organisms are identical or if there are differences between the two strains

Question 34

What can typing be used to do?

Answer 34

Identify any difference, cannot claim isolates are identical

Question 35

Give an example of where typing could be used in infection investigation

Answer 35

Could be used to identify that a surgical wound infection isolates are indistinguishable from an operating theatre washing basin, hence identify where the infection originated

Question 36

What are the main typing techniques?

Answer 36

• Simple lab typing
• Serological testing
• Molecular typing

Question 37

What is looked at in simple lab typing?

Answer 37

Appearance on agar

Question 38

What does molecular typing use?

Answer 38

Restriction endonucleases

Question 39

What happens in molecular typing?

Answer 39

Restriction endonucleases digest plasmid DNA or ribosomal RNA from the pathogen and check for the binding patterns produced

Question 40

How is molecular typing interpreted?

Answer 40

Any identical bacteria will produce similar banding patterns