1 The diagnostic laboratory process

Question 1

sampling - urine

Hvad er den bedste måde?

Answer 1

Urine samples should be taken by cystocentesis

In case of almost empty bladder:
• Catheter (males)
• Mid-stream urine (females)

Question 2

sampling - skin

Pustel

Answer 2

Desinf af overfladen ikke nødvendig
Fjern hår i område (steril saks)
Punkter pustel med en nål – overfør ekssudat fra spids af nål til en steril vatpind -> transportmedium

Question 3

sampling - skin

Kruste

Answer 3

Desinf af overfladen ikke nødvendig
Løft spidsen af krusten med steril pincet og berør huden under krusten med steril podepind
Vastskaber lægges i transportmedium

Question 4

sampling - skin

Epidermal collarette

Answer 4

Desinf af overfladen ikke nødvendig
fjern hår i omr omkring kollaretten med steril saks. Berør indre overflade af kollaretten med en steril vatpind
- Læg i transportmedium

Question 5

sampling - skin

Genereliseret pyodermi eller lokal dyb pyodermi, fx lukket furunkel

Answer 5

Anæstesi
Fjern hår i omr. Med steril saks
Desinficer område med 70%ethanol
Tag biopsi med en biosinål/punch med en diameter på 3-4 mm
Læg biopsien i en steril beholder, evt fugtet med en dråbe sterilt isotonisk saltvand
Suturer biopsihullet

Question 6

sampling – respiratory tract

Answer 6

Upper airways
• Preferably take sample by rhinoscopy
• Avoid contamination from external nares
Lower airways
• Preferably bronchoalveolar lavage

Question 7

sampling – genital organs

Answer 7

Endometritis, metritis, pyometra

• Sample from cranial vagina or uterus using a doubleguarded culture-swab:

Question 8

MacConkey agar

selective/indicative

Answer 8

Lactose postive bliver røde

Lactose negative bliver gule

Question 9

Er det gram + (positive) og kokker

kan det være?

Answer 9

Strep og staph

Question 10

Er det gram - (negative) og stave

kan det være?

Answer 10

Fermentative eller nonfermentative

Question 11

Streptokokker er:

når man skal diff. fra staph

Answer 11

små
katalase neg -
(Glucose ferm. ej motile)

Question 12

Staphylokokker er:

når man skal diff. fra strep.

Answer 12

medium
katalase pos +
(Glucose ferm. ej motile)

Question 13

hvilke er nonfermentative?

Answer 13

Pseudomonas
Bordetella
Acinetobacter

Question 14

Hvilke er fermentative?

Answer 14

Enterobacteriaceae (oxy neg - ):
Escherichia coli
Salmonella
Proteus

Pasteurellaceae (oxy pos +):
Pasteurella
Actinobacillus
Mannheimia

Question 15

Hvad er Maldi-TOF????

Answer 15

Matrix-assisted laser desorption/ionization
time-of-flight mass spectrometry

A relatively new method for distinction of bacterial species based mainly on their protein content
• Sample (colony material) is placed on a slide and overlaid with a matrix, which dissolves the cell wall and binds released material (mainly proteins)

• A laser shoots on the sample matrix spot causing it to
volatilize
• The ions formed are accelerated by a high voltage
supply and then allowed to drift down a flight tube where
they separate according to mass
• Arrival at the end of the flight tube is detected and recorded by a high speed recording device
• The Time-Of-Flight of the ionized molecules is converted
into mass, and a spectrum for the size of all absorbed
molecules is made
• Comparison to reference spectra in a database representing well characterized bacteria is used to determine the species