Basics of Microbiology: Bacterial Culture Flashcards
Blood Agar is differential in that different bugs grow with different patterns on it. 3 patterns are:
Blood Agar is Commonly used to differentiate species of _ with 2 notable exceptions:
streptococcus
pseudomonas, Beta-hemolytic but produces a blue-green color
Staph Aureus Beta hemolytic
Chocolate Agar grows:
H. Influenzae
Contains red blood cells that are lysed,
Contains NAD (factor V) and hemin (factor X)
(H flu won’t grow on blood agar unless S. Aureus present)
Thayer-Martin Media aka _ grows _
VPN/VCN
Neisseria (often from sites with lots of other flora like Throat, genitalia & therefore Need very selective media)
Supplemented chocolate agar with:
Vancomycin: Kills most Gram-positive organisms
Colistin (polymyxin): Kills most Gram-negatives {Except Neisseria}
Nystatin: Kills most fungi
VPN stands for:
Vancomycin: Kills most Gram-positive organisms
Colistin (polymyxin): Kills most Gram-negatives {Except Neisseria}
Nystatin: Kills most fungi
(called Thayer-Martin Media- grows Neisseria)
Bordet-Gengou Agar aka grows:
aka Potato Agar
Bordetella pertussis
(whooping cough)
Loeffler’s Media/Tellurite Plate selective for:
Corynebacterium diphtheriae
C. diphtheria reduces potassium tellurite to tellurium and Produces gray-black colored colonies
Lowenstein-Jensen Agar
Mycobacterium tuberculosis
remember, this grows SLOWWWWW, better to use stain instead (Ziehl-Neelsen stain)
Eaton’s Agar grows:
mycoplasma pneumonia
(no cell wall, requires cholesterol & cystein to grow)
also slow growing, can diagnose mycoplasma pnumo with serology- (antibody testing), PCR(bac DNA) and cold agglutinins (IM antibodies)
MacConkey’s Agar selective for _ because of _ & differential for _
gram (-) bacteria
Contains bile salts that inhibit Gram (+) bacteria growth
differential for lactose fermenters
Lactose fermentation produces acid → turns agar pink
Non-lactose fermenters are colorless
Eosin-Methylene Blue Agar similar to -
Similar in function to MacConkey’s Agar
Eosin Y and methylene blue as inhibitors of Gram (+) bacteria
Also differential for lactose fermenters
Lactose fermenters (Escherichia coli) appear as colonies with green metallic sheen or blue–black to brown color
Bacteria that do not ferment lactose appear as colorless or transparent colonies
Sorbitol MacConkey Agar selective for
Detection of E. Coli O157:H7 strains (Shiga-like toxin)
O157:H7 cannot ferment sorbitol (other E. Coli can)
O157:H7 grows as colorless colonies on this medium
Other E. Coli produce pink colonies
Buffered Charcoal Yeast Extract selective for
Legionella
b/c contains dyes that give Legionella distinct color
Antibiotics added: inhibits growth of competing bugs
Very important to culture this bacteria
(Can contaminate water supplies / Cause outbreaks)
Sabouraud’s Agar selective for:
fungi
Developed by a French dermatologist to ID Growth of fungi in skin, hair, or nails (dermatophyte)
Acid or antibiotics inhibit bacterial growth
