Unit 3: Common Culture Media: Agar Plates Flashcards
classification of BAP and why
differential- shows hemolysis
enriched- 5% sheep blood
classification of CNA (colistin-nalidixic acid) and why
BAP with
enriched- 5% blood
selective- antimicrobials
what makes CNA selective
10.0 mg of colistin and nalidixic acid. selects for gp by inhibiting gn
what bacteria is CNA useful of inhibiting
swarming gram -ive bacillus called Proteus
why should hemolysis not be interpreted by CNA
drugs in media interfere w/hemolysis
classification of CHOC and why
enriched-horse rbc
classification of MAC and why
selective-crystal violet + bile salts inhibit gp
differential-lactose fermentation detected by neutral red pH indicator
classification of BRUcella and why
enriched-added hemmin, vitamin K, blood
differential-hemolysis
why is sheep blood used
contains NADase an enzyme that destroy NAD (V factor)
why can’t you determine hemolysis on CHOC plates
red blood cells are already lysed (in house) when prepared or missing (commercial)
In house CHOC plates vs commercial
- both provide X (hemin) and V factors (NAD)
- in house will have lipids
- commerical will have no lipids
growth on CHOC w/o growth on BAP means and e.g.
fastidious org like Haemophilus influenzae and Neisseria gonorrhoeae
growth on BAP but not on commercial CHOC means
organism requires lipids
results of differential from MAC plate
LF- pink to magenta are opaque
NLF are colourless and clear
MAC BCIT formula only grows
non fastidious gnb
