Diagnosis and Management - Microbiological Sampling

Question 1

Describe the three techniques for sampling pus (3)

Answer 1

• Swabs
• Aspirates
• Paper points

Question 2

How are swabs sent to the lab? (1)

Answer 2

Send in transport medium

Question 3

What transport mediums are there? (4)

Answer 3

• Water
• Isotonic salts
• Reducing agent
• Sometimes activated charcoal

Question 4

What should happen after an aspirate has been taken? (2)

Answer 4

• Leave in syringe

- Make needle safe

Question 5

How are paper points sent to the lab? (1)

Answer 5

Sent in transport medium

Question 6

What sampling techniques are used for mucosa and skin? (2)

Answer 6

• Swabs

- Oral rinse

Question 7

What types of swabs are there for mucosa and skin? (3)

Answer 7

• Dry sites – clean mucosa prior to incision, send in transport medium
• Suspected viral – viral transport medium
• Vesicle fluid – aspirate into a tuberculin syringe

Question 8

Give examples of viral transport mediums (5)

Answer 8

• Protein stabiliser
• Salts
• Gelatin
• Water
• Sometimes antibacterial agent

Question 9

How is an oral rinse carried out? (3)

Answer 9

• 10ml sterile saline
• Rinse mucosa 30 seconds
• Spit into sterile bottle/tube

Question 10

What information is required in a specimen request form? (5)

Answer 10

• State type of sample
• Where from
• Clinical signs & symptoms,
• Provisional diagnosis
• Ask for “culture and sensitivity”

Question 11

How should samples be sent to the lab? (2, 1+1, 1+1, 1)

Answer 11

• Post
• Label as ‘Diagnostic specimen’ or ‘Biological Substance, Category B’
• Place in a leak proof, rigid container’ (conforming with pi 650 – UN3373)
• A primary receptacle, secondary packaging, outer packaging
• Wrap aspirates in absorbent material in case of leakage
• e.g. cellulose wadding, paper towels
• Itemise list of contents enclosed between the secondary and outer packaging

Question 12

How long does it usually take for preliminary results from the lab? (1)

Answer 12

Normally 48hrs, possible after 24hrs

Question 13

What do the results NOT give, what do they give? (2)

Answer 13

• Do NOT give species (most times)

- Should give antimicrobial sensitivities

Question 14

For bacteria, what are specimens plated onto? (1+2, 1+1)

Answer 14

• Enriched media
• Blood agar
• CO2
• Fastidious anaerobe agar – anaerobic conditions
• MZ disc added for anaerobic culture

Question 15

For fungi, what are specimens plated onto? (1)

Answer 15

Sabouraud’s agar

Question 16

What other types of samples are there? (2)

Answer 16

• Gram stain

- Germ-tube test (if candida)