Microbial Culture Technology Flashcards
-cells are grown under controlled conditions, generally outside their natural environment.
CELL CULTURE
contains an appropriate vessel with a substrate or medium that supplies the essential nutrients.
CELL CULTURE
The original media used by __ – urine or meat broth
Louis Pasteur
macroscopically visible collection of millions of bacteria originating from a single bacterial cell
Colony
Cooked cut potato by __- the earliest solid medium
Robert Koch
not satisfactory; liquefy at 24oC
Gelatin
who introduced the agar medium
Franny Hesse
Used for preparing solid medium obtained from seaweeds
Agar
No nutritive value; Not affected by the growth of the bacteria.
agar
agar melts at __ and sets at __
Melts at 98oC;
sets at 42oC
Types of culture media (3)
Based on their consistency
Based on the constituents/ ingredients
Based on Oxygen requirement
Types of culture media Based on their consistency
a) solid medium
b) liquid medium
c) semi solid medium
Types of culture media Based on the constituents/ ingredients (4)
a) simple medium
b) complex medium
c) synthetic or defined medium
d) Special media
Special media (8)
◦ Enriched media
◦ Enrichment media
◦ Selective media
◦ Indicator media
◦ Differential media
◦ Sugar media
◦ Transport media
◦ Media for biochemical reactions
Types of culture media Based on Oxygen requirement
- Aerobic media
- Anaerobic media
contains 2% agar;
Colony morphology, pigmentation, hemolysis can be appreciated.
Solid media
example of solid media ((2)
nutrient agar, blood agar
no agar.; For inoculum preparation, Blood culture, for the isolation of pathogens from a mixture.
Liquid media
example of liquid media
Nutrient broth
0.5% agar.
Semi solid medium
example of Semi solid medium
Motility medium
example of simple/basal media (2)
NB, NA
NB consists of __, __ , __
peptone, meat extract, NaCl
NB + 2% agar =
nutrient agar
They have added ingredients. Provide special nutrients
Complex media
Media prepared from pure chemical substances and its exact composition is known
Synthetic or defined media
example of Synthetic or defined media
peptone water – 1% peptone + 0.5% NaCl in water
Substances like blood, serum, egg are added to the basal medium.
Enriched media
Used to grow bacteria that are exacting in their nutritional needs.
Enriched media
examples of Enriched media (2)
Blood agar, Chocolate agar
Liquid media used to isolate pathogens from a mixed culture.
Enrichment media
Media is incorporated with inhibitory substances to suppress the unwanted organism.
Enrichment media
examples of enrichment media (2)
◦Selenite F Broth;
Alkaline Peptone Water
◦Selenite F Broth – for the isolation of __, __
Salmonella, Shigella
The inhibitory substance is added to a solid media.
Selective media
examples of selective media (5)
-Mac Conkey’s medium
-Thiosulfate–citrate–bile salts–sucrose agar (TCBS)
-Löwenstein-Jensen (LJ) medium
-Wilson and Blair medium
selective media for V. cholerae
Thiosulfate–citrate–bile salts–sucrose agar (TCBS)
egg-based medium; M. tuberculosis
Löwenstein-Jensen (LJ) medium
combination of bismuth and sodium sulphite ; S.typhi
Wilson and Blair medium
–inhibits the growth of most bacteria associated with Enterococcus species. Diphtheria bacilli
Potassium tellurite medium
These media contain an indicator which changes its colour when a bacterium grows in them
Indicator media
examples of Indicator media (3)
◦Blood agar
◦Mac Conkey’s medium
◦Christensen’s urease medium
____- pink colonies
____- colorless colonies
Lactose fermenters- pink
Non lactose fermenters
Media used for transporting the samples.
Transport media
Delicate organisms may not survive the time taken for transporting the specimen without a _
transport media
examples of transport media (2)
Stuart’s medium
Buffered glycerol saline
non nutrient soft agar gel containing a reducing agent
Stuart’s medium
enteric bacilli
Buffered glycerol saline
examples of Anaerobic media (2)
-Robertson’s cooked meat medium
-Thioglycolate medium.
Culture methods include: (7)
Streak culture
Lawn culture
Stroke culture
Stab culture
Pour plate method
Liquid culture
Anaerobic culture methods
Used for the isolation of bacteria in pure culture from clinical specimens.
STREAK CULTURE
what wires are used in streak culture?
Platinum wire or Nichrome wire
Provides a uniform surface growth of the bacterium.
LAWN CULTURE
Uses of lawn culture (3)
◦bacteriophage typing.
◦ Antibiotic sensitivity testing.
◦preparation of bacterial antigens and vaccines.
are prepared by flooding the surface of the plate with a liquid suspension of the bacterium.
lawn cultures
___ is made in tubes containing agar slope / slant
Stroke culture
◦Provide a pure growth of bacterium for
slide
agglutination
stroke culture
Prepared by puncturing a suitable medium – gelatin or glucose agar with a long, straight, charged wire.
stab culture
uses of stab culture (3)
◦Demonstration of gelatin liquefaction
◦Oxygen requirements of the bacterium under study
◦Maintenance of stoke cultures.
Agar medium is melted (15 ml) and cooled to 45oC.; 1 ml of the inoculum is added to the molten agar.; poured to a sterile petri dish; Incubated at 37oC
POUR PLATE CULTURE
uses of pour plate culture (2)
◦ Gives an estimate of the viable bacterial count in a suspension.
◦ For the quantitative urine cultures.
are inoculated by touching with a charged loop or by adding the inoculum with pipettes or syringes.
Liquid cultures
uses of liquid culture (3)
◦ Blood culture
◦ Sterility tests
◦ Continuous culture methods
does not provide a pure culture from mixed inocula.
liquid culture
