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Flashcards in Bacterial Diagnostics Deck (22):
1

Sample types(7)

Sample types

  • blood
  • swabs
  • transudates/exudates (other fluids)
  • urine
  • feces
  • vomitus
  • tissues

2

Blood samples

sites

tests

Blood samples

*maintain sterility*

  • veinpuncture sites
    • jugular
    • femoral
    • cephalic
    • caudal vein (cattle)
    • ear veins (rabbits+pigs)
  • Bloos can be used for:
    • culture
    • serology
    • diagnostics

3

Vacutainer Colors(6)

Vacutainer Colors

  • Red- no additive or clot activator (for serum)
  • Tiger top- cloct activator/serum separator (also for serum)
  • Purple top- KEDTA anticoagulant (CBC)
  • Green- lithium heparin anticoagulant (chemistries)
  • Green tiger- lithium heparin and plasma separator
  • Light blue- sodium citrate anticoagulant

 

4

Swabs(6) and Scrapes(2): Locations

Swab and Scrape: locations

Swabs

  • ears
  • wounds
  • abscesses
  • conjunctiva
  • joint
  • genitourinary areas

Scrapes

  • skin
    • ** for mycology and parasitology
  •  

5

Transudates/Exudates (7)

Transudates/Exudates= Misc. fluids

  • abscess
  • abdominal fluids
  • oral fluid
  • nasal fluid
  • CSF
  • joint fluid
  • TTW

6

Urine: collection methods (4)

Urine: collection methods (4)

***very important in practice*** (exam)

There is a order of preference for urine collection methods:

1. cystocentesis- with needle

2. catheter

3. free catch

4. environmental

7

Feces (3) and Vomitus (2): collection methods

Feces (3) and Vomitus (2): collection methods

Feces- usually for parasite diagnostics

  • fecal loop
  • fecal swab
  • environmental

Vomitus

  • same/similar
  • uncommon to collect vomit

8

Tissue collection (2)

Tissue collection (2)

  • biopsy
  • necropsy

9

Methods for direct examination of sample

Methods for direct examination of sample

  • Stain!!!
  • Culture- identification and antibiotic susceptibility

10

Stains (4)

Stains

  • Histopathology (h&e)
    • shape
    • cellular association(intra or extra)
  • Romanowsky/Wright (diff-quik)
    • everything will be purple
    • shows shape
  • Gram Stain- bacteria
    • shape
    • surface characteristice (+/-)
  • Acid Fast Stain
    • mycobacterium
    • nocardia
    • cryptosporidium

11

Gram stain

 

 

 

 

Gram stain

Remember:

  • stains peptidoglycan layer in gram + cells (blue)
  • gram - cells dont hold the crystal violet stain becuase less peptidoglycan.  dye red with follow up stain. 

** shapes and groupings can help with diagnostics

  • staph- grapes
  • strep- chains

A image thumb
12

Making the decision to culture

Things to consider...

  • time
  • cost
  • supplies
  • expertise

DIAGNOSTIC LABS MAKE MORE SENSE THESE DAYS

13

Bacterial Nutrition

Bacterial Nutrition-for cultures

  • lots of carbon and nitrogen
  • peptones (amino acids and peptides)
  • some vitamines 

14

Bacterial environmrntal conditions

Bacterial environmrntal conditions

  • temperature
    • mesophiles-body temp
    • thermophiles
    • psychrophiles- cold
    • psychrotropes
  • ph
    • acidophiles
    • neutrophiles
    • alkaliphiles
  • humidity
  • atmospheric composition

 

15

Oxygen requirements 

6 types 

different location in culture based on requirements

Oxygen requirements

  • obligate aerobes (1)
  • obligate anerobes (2)
  • faculative either (3)
  • microaerophiles (4)- killed by high o2 but like some
  • aerotolerant anaerobes (5)
  • capnophiles - like co2 (not shown)

***grow differently based on preferences see diagram

A image thumb
16

Culture (3)

Culture (3)

  • Agar
    • nutrient media
    • selective media
    • diffferential media
  • Broth
    • nutrient broth
    • enrichment broth
  • Biochemical Testing
    • enzymes
    • fermentation

17

Agar- specifics

Review agar slides in powerpoint for specific examples

  • basic nutrient media- food
  • enriched nutrient media- food to grow extra good
  • selective media- only allows growth of target
  • differential media- results in different behavior of different organisms

18

ID test strips

ID test strips

  • save space and resources and time
  • lots of tests in one strip
  • gives you diagnostic bacterial info! 

19

Molecular diagnostics (4 specifics)

Molecular diagnostics

  • 16s ribosomal RNA PCR = GOLD STANDARD
  • real-time PCR
  • MALDI-TOF- based on molecular weights of component proteins
  • Snap tests
    • ELISA- looks for antibodies or antigens

20

antibiotic sensativity vs. resistance

TESTS

  • Kirby-baur disk diffusion
    • there are antibiotics in a place, see to what degree it deters batcherial growth
  • Microdilution
    • different concentrations of antibiotics in different wells.  determine at what dilution bacteria ceases to grow

21

Sample Results

 

Sample Results

  • S: senative
  • R: resistant
  • I: intermediate
  • NI: no interpretation

22

Diagnostics for parisitology

Diagnostics for parasitology

  • based on fecal sedemintation.  FLOAT eggs
  • send samples to lab 
  • blood samples can be used sometimes too

WONT ASK ANY QUESTIONS ABOUT PARASITOLOGY