LESOON 12: CULTURE MEDIA Flashcards
(79 cards)
Usually confirmed by isolating and
culturing microorganisms in artificial media.
Laboratory diagnosis of an infection
Bacteria and fungi are cultured in either
liquid (broth) or on solid (agar) artificial media.
Pioneered the use of
agar as a base for culture media as suggested by Fannie Eilshemius Hesse, the wife
of Walther Hesse, one of Koch’s a assistance
Robert koch
Developed the Petri dish (plate), a container for solid culture.
Richard Petri
developed the pour plate method and was the first to use solid culture media
for culture of bacteria.
Robert Koch
A nutrient material prepared for the growth of microorganisms in a
laboratory is called a
culture medium.
When microbes are introduced into a culture medium to initiate growth,
they are called an
Inoculum
The microbes that grow and multiply in or on a culture medium are referred
to as
Culture
: is the process of growing microorganisms in culture by taking bacteria
from the infection site (i.e. in vivo environment)
bacteria culture within the living
some means of specimen
collection and growing them in the artificial environment of the laboratory (i.e. the in
vitro environment)
bacteria culture growth outside laboratory
a laboratory culture containing a single species of organism.
Pure culture: a
Bacterial cultivation has three main purposes :
i. To grow and isolate all bacteria present in an infection.
ii. Infection and contaminants or colonizers:
To determine which of the bacteria that
grow are most likely causing infection and which are likely contaminants or
colonizers.
iii. Identification and characterization:
To obtain sufficient growth of clinically relevant
bacteria to allow identification and
Ingredients of Culture Media
Some of the components of culture media are as follows:
- water
- agar
- peptone
- Yeast Extract
- malt Extract
- Blood And Serum
often suitable for culture media, particularly if it has a low
mineral content, however glass-distilled or demineralized water
Tap water
Prepared from a variety of seaweeds and is now universally used for preparing solid media.
Agar does not add to the nutritive
properties of a medium and is not affected by the growth of bacteria.
Agar
the nutritive properties of a medium and is not affected by the growth of bacteria. The melting and solidifying points of agar solutions.
At the concentrations
normally used,
most bacteriological agars melt at about 95°C and solidify only when
cooled to about 42°C.
Another almost universal ingredient of common media
peptone
It is a complex mixture of partially digested proteins.
Peptone
The important constituents are
peptones, proteoses , amino acids, a variety of inorganic salts including phosphates, potassium and magnesium, and certain accessory growth factors such as nicotinic
acid and riboflavin.
Commercially available peptones or digest broth can be used.
Is also available commercially and is known as LabLemco.
Meat Extract
It contains a wide range of amino acids, growth factors and
inorganic salts.
Yeast Extract
