Ch. 39: Sample Collection and Handling

Question 1

What are the two common collection methods of microbiology sample collection?

Answer 1

Aspiration and swabbing (Imprints may also be an option)

Question 2

The specific collection method depends on what?

Answer 2

The location of the sample area/lesion and the testing desired

Question 3

What collection method is the least suitable method and why?

Answer 3

Sterile cotton swabs; contamination risk is high and cotton can inhibit microbial growth

Question 4

Sterile cotton swabs aren’t likely to be able to collect what bacteria?

Answer 4

Anaerobic; oxygen an be trapped in the fibers, making the recovery of anaerobic bacteria less likely

Question 5

What collection is preferred over sterile cotton swabs?

Answer 5

Rayon or Dacron swabs

Question 6

What must be used if there are delays in processing samples?

Answer 6

A rayon swab in a transport media (Culturette) to preserve the quality

Question 7

Samples that are to be immediately processed an usually be collected using what?

Answer 7

Sterile cotton swabs; but this is not preferred

Question 8

The best results can be obtained if specimens are collected from sites that would normally be ______.

Answer 8

Sterile

Question 9

What sample collection sites will not yield the best results due to the contamination of the area?

Answer 9

Ear or fecal samples

Question 10

What technique must be used when collecting samples for microbiology testing?

Answer 10

Aseptic technique

Question 11

What is the required data needed prior to collecting microbiology samples?

Answer 11

• Owner’s name
• Clinic’s name
• Address
• Phone number
• Species
• Patient name
• Age
• Sex
• Number of animals dead or affected
• Duration of the problem
• Major signs observed

Question 12

What is the most common cause of diagnostic failure with microbiology samples?

Answer 12

Specimen contamination

Question 13

When collecting dermatophyte specimens for culture, what is the proper technique?

Answer 13

Clean the skin lesion to remove some of the surface contamination, and collect specimens from the lesion periphery

Question 14

What are the best samples ( likely to contain viable organisms) for dermatophyte culture?

Answer 14

Broken hair shafts and dry skin scales

Question 15

How can hairs be collected?

Answer 15

Plucking or a toothbrush can be used

Question 16

If using a toothbrush to collect sample hairs, what is the proper technique?

Answer 16

Obtain a new human toothbrush and brush the suspected lesion for 1-2 minutes

Question 17

For fungal testing, hair, nails, and skin can be put in what container?

Answer 17

A paper envelope

Question 18

With respiratory diseases, where are viruses often present?

Answer 18

Nasal and pharyngeal secretions

Question 19

When collecting samples for viral specimens, what should be the method of collection?

Answer 19

Mucosal scrapings rather than swabs of secretions should be taken

Question 20

What tool is useful for mucosal scrapings?

Answer 20

Sterile wooden tongue depressors

Question 21

Viral specimens should also be collected for what indirect studies?

Answer 21

Serology, hematology, histology, and bacteriology

Question 22

Viral diseases are often complicated by what that act as secondary invaders?

Answer 22

Pathogenic bacteria

Question 23

Specimens for histology testing should be contained in what?

Answer 23

10% Formalin, should contain a thin section of tissue

Question 24

Is it okay for histology specimens to be frozen?

Answer 24

No, this causes tissue artifacts that may be difficult to differentiate from a pathologic process

Question 25

Virus titers decrease as temperature ______.

Answer 25

Increases; this is why they need to be refrigerated

Question 26

If samples are being shipped with dry ice, why must the samples be in an airtight container?

Answer 26

To prevent the entry of carbon dioxide. Carbon dioxide gas from the dry ice can lower the pH of fluid and kill any pH-liable viruses

Question 27

How should small pieces of tissues, fecal material, or mucus be stored?

Answer 27

In vials filled with 50% glycol and stored at 4 degrees celsius

Question 28

What should be added to fecal and fluid samples to prevent the over-dilution of virus particles?

Answer 28

A fixative should be added at a max fixative-to-sample ratio of 1:1

Question 29

Virus transport media should be used with urine samples.

True or False?

Answer 29

False

Question 30

How should urine be packaged and sent off?

Answer 30

In a sterile container and chilled if it is to arrive at the lab in 24 hours, if not, it should be shipped frozen