2ND PRELIM Flashcards
A growth of microbes
Culture
Microbial population
Colony
When a colony is consist of only one type of cell it is called
Pure culture
3 classification of media
Physical state
Chemical composition
Functional type
What are the tree physical state
Liquid
Semi-solid
Solid
These media are commonly termed as broth, milk, infusion
Liquid media
Exhibits a clot like consistency
Semi-solid media
What are the two solidifying agents?
Agar and gelatin
Provides firm surface
Solid media
2 forms of solid media
Reversible
Non-reversible
Contain mixture of nutrients that support pathogen and non-pathogen growth
General purpose media
Designed to increase the number of microbes without stimulating the rest of the bacterial population
Enrichment media
Contains agent that inhibit the growth of a certain microbe and thereby only a certain microbe can grow
Selective media
Various type of microorganisms can grow it is designed to display visible differences of microorganisms
Differential media
Colonies range from pinpoint(less than 1mm) to as large as 5-10mm in diameter. Only well-separated colonies should be measured since they tend to have larger diameter when crowded.
Size
The periphery of the colonies may be entire, with rounded projections, notched, threadlike, filamentous, serrated, or lobate
Margin
Classified as smooth(shiny, glistening), rough (dull, granular), mucoid (slimy or gummy), wrinkled, concentric, contoured and etc., It can serve as indicator of virulence.
Surface texture
Can be flat, raised or convex
Elevation
Can be determined by touching the colony with transfer with a transfer needle. Classified as butyrous (butterlike), viscous, stringy, dry, brittle, powdery consistency.
Consistency
Colonies may be transparent, translucent, or opaque.
Optical features
Differential isolation and presumptive identification of Group D streptococci and enterococci
Bile esculin agar
Determination of hemolytic reactions
Blood agar
Isolation of Bordatella pertussis (whooping cough) commonly used – colonies resemble mercury droplets
Bordet-Gengou agar
Enrichment medium for Legionella species
Buffered Charcoal-yeast extract agar (BCYE)
Selective medium for Campylobacter species
Campy blood agar
Cultivation of Haemophilus species and pathogenic Neisseria species
Chocolate agar (CHOC)
Selective isolation of gram-positive cocci
Columbia colistin-nalidixic agar
Isolation and differentiation of lactose-fermenting and non-lactose fermenting enteric bacilli
MacConkey Agar
Selective isolation of staphylococci
Mannitol salt agar
Selective for Neiserria gonorrhea
New York city agar
Enrichment medium for the isolation of Salmonella species
Selenite broth
Selective for N. gonorrheae and N. meningitidis
Thayer martin agar
Selective and differential medium for Vibrio species
Thiosulfate - citrate bile salt sucrose agar
