Enrichment, Selective and Differential Culture Media: A Comprehensive Guide, Summaries of Evolutionary biology

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ENRICHMENT, SELECTIVE ANDDIFFERENTIAL CULTURE MEDIA Cultivation is the process of propagatingmicroorganisms to grow by providing the properenvironmental conditions Omid Tadayoun

supervised: berzsu

ENRICHMENT MEDIA

Basic principle is to control the nutrients and cultureconditions in such a way that it suits mainly to aspecific species

y

temperature, air supply, light, pH

When we assume low amount of potentialpathogens being present in the specimen, theyhave to be enriched first, to multiply up the lownumber – e.g. serum bouillon, dextrose bouillon,chopped meat bouillon

Promotes the growth of a particular organism byproviding it with the essential nutrients, and rarelycontains inhibitory substances to prevent thegrowth of normal competitors

SELECTIVE MEDIA

Eosin-methylene blue agar (EMB)

y

Contains methylene blue, toxic to Gram + bacteria,allowing only the growth of Gram – bacteria

MacConkey agar (MCK)

y

For Gram – bacteria

Buffered charcoal yeast extract agar (BCYE)

y

Selective for certain Gram - , for example Legionella.

Mannitol salt agar (MSA)

y

Selective for Gram + bacteria

Hektoen enteric agar (HE)

y

Shigella, Salmonella

Thiosulfate citrate bile sucrose (TCBS)

y

Vibrio cholerae

DIFFERENTIAL MEDIA

Distinguishes one microorganism type from anothergrowing on the same media on a difference in thecolony appearance

y

Color, shape, growth pattern

y

Dyes in the medium, pH indicators

Eosin-methylene blue agar (EMB)

y

Differential for lactose and sucrose fermentation

MacConkey agar (MCK)

y

Differential for lactose fermentation

Mannitol salt agar (MSA)

y

Differential for mannitol fermentation