Infection control

Question 1

Name some antibiotic resistant organisms?

Gram positive and Gram negative

Answer 1

Gram positive
MRSA (meticillin resistant S.aureus)
Vancomycin resistant enterococcus (VRE)

Gram negative Enterobacteriaceae

• Extended spectrum - lactamse producing Enterobacteriaceae (ESBL producer)
• Carbapenem resistant enterobacteriaceae (CRE)
• Carbapenemase producing pseudomonas

Question 2

Why is HCAI (healthcare associated infections) an issue?

Answer 2

• Chronic disease
• Invasive medical devices
• Elderly population
• Immunosuppression
• More complex procedures
• Increasing antibiotic resistance

Question 3

Describe the chain of infection

Answer 3

Infectious agent
Reservoir
Portal of exit
Mode of transmission
Portal of entry
Susceptible host

Question 4

Discuss mode of transmission

Answer 4

• Direct or indirect contact via fomites or ingestion - BBVs, diarrhoea, MRSA C. difficile, Group A streptococcus, N.gonorrhoea
• Droplet transmission - N.meningitis, norovirus. diphtheria, pertussis, pneumonic plague
• Aerosol (airborne) transmission - TB, chicken pox, influenza, viral haemorrhagic fever, measles

Question 5

What are contact precautions?

Answer 5

-For patients infected/volonised with organism transmitted by direct or indirect contact - gastroenteritis, fever in patient returned from tropics, C.difficile, MRSA
Single room, gloves, apron, disposable masks/eye protection if splash exposure

Question 6

What are droplet precautions?

Answer 6

For organisms transmitted in droplets, these travel only short distances
Meningism, fever with cough/rash, vomiting, N.meningitis, mumps, rubella
Single room if possible, surgical mask when in touching distance of patient or cough inducing procedure

Question 7

What are airborne precautions?

Answer 7

Can be widely dispersed e.g. TB, chicken pox, measles, flu, chicken pox
Single room, apron, gloves, high efficiency filter mask

Question 8

What different types of medical devices are there?

Answer 8

Invasive medical devices - long term or short term - all break the skin or mucous membrane barrier - CVC, PVC, urinary catheters, dialysis lines etc

Indwelling prosthetic devices - usually long term devices which are buried into tissue under skin - heart valves, joints, pacing units etc

Question 9

Transmission depends on what 3 factors?

Answer 9

• No MO’s shed
• No MO’s required to infect a fresh host (infection efficiency)
• MO’s stability in environment

Question 10

What is fomite transmission and what are nosocomial infections?

Answer 10

Fomite transmission is transmission via inanimate objects - door handles etc

Nosocomial infections are infections acquired during a hospital stay - major public health concern. Antibiotic resistance - C.difficile, S.aureus
Good hygiene and sanitation are vital

Question 11

Influenza causes endemic, epidemic and pandemic disease - what are these?

Answer 11

Endemic - present in community at all times at a relatively low to medium frequency but at a steady state

Epidemic - Sudden severe outbreak within a region or a group

Pandemic - occurs when an epidemic becomes widespread and affects a whole region, continent or the entire world

Question 12

What makes a pandemic?

Answer 12

• Antigenic shift
• Most people have no immunity
• Attack rate is high - spreads rapidly
• Mortality can be high

Question 13

What is notifiable disease?

Answer 13

Any disease that is required to reported to government by law
provides early warning of possible outbreaks

Reference labs to identify e.g. Meningococcal disease
Public health action - identify close contacts and arrange antibiotics, vaccinations
Public awareness - public should be aware of key signs and symptoms and to seek urgent medical advice if concerned