1. CULTURE MEDIA
PRESENTED BY;
MELVA TIEMPO
JULIUS CORTEZO
MARK ALDINNE MOSNIT
DARYL JAY SANICO
GONZALO SALADO
JHONDIE MAYOLA
RAYMOND SIMEROS
2. Culture Media
✓A liquid or gel designed to support
the growth of microorganisms or
cells.
✓Culture medium-nutrients prepared
for microbial growth
✓ Inoculation- introduction of
microbes intomedium
✓ Culture/Colony- microbes growing
in/on culture medium.
3. ✓ Robert Koch- described his culture
techniques in 1881.
✓Fanny/Frau Hesse- suggested the use
of agar.
✓Richard Julius Petri- invented the
glass Petridishes.
✓Joseph Lister- the first person to
obtain a preculture of bacterium
(Streptococcus lactis) in a liquid medium.
4. Classification of Culture Media
Based on Whether the Exact
Contents are Known
✓Chemically defined media-
exact chemical composition is
known
✓Complex media- exact
contents are not known, from
extracts and digests of yeasts,
5. Liquid and Solid Media
✓Liquid media- or broths are contained in
tubes,referred to as tubed media.
✓Solid media- prepared by adding agar to
liquid media and then poured into test tubes or
Petridishes, where the media solidifies.
>Agar plate -one grown on a medium, usually
agar orgelatin, on a Petri dish
>Agar slant -one made on a slanting surface of
a solified olidifieda tube, the tube being tilted
to provide greater surface area for growth.
>Agar butt/deep -one in which a tube of solid medium
isnoculated by a needle thrust deep into the contents.
8. Examples:
>MacConkey agar- screen for S. aureus
and is selective for Gram (-) bacteria.
>Phenylethyl alcohol agar (PEA) and
colistin-nalidixic acid agar (CNA)-
inhibit growth of Gram (-) bacteria.
>Thayer-Martin agar and Martin-Lewis
agar- selective for N. gonorrhoeae.
>Mannitol salt agar (MSA )-only for salt-
tolerant(haloduric) bacteria
>Eosin methylene blue agar (EMB) –
selective against gram-positives
9.
10. Differential Medium
✓Permits the differentiation of
organisms that grow on the medium.
✓Reveals the presence of 2 or more
similar microorganisms by differences in
the appearance of their colonies.
11. Examples
>MacConkey agar- used to differentiate various Gram (-)
bacilli that are isolated from fecalspcimens.
•Gram (-) bacteria are able to ferment lactose produces
pink colonies, those are unable to ferment lactose produce
colorless colonies.
•Differentiates between LF and NLF Gram (-) bacteria.
>Mannitol salt agar- used to screen for S.aureus, pink to
yellow.
>Centrimide agar -used for the differentiation of strains
ofPseudomonas spp.
12.
13. Enriched Medium
>Broth or solid medium containing rich supply of
special nutrients that promotes the growth of
fastidious organisms.
>Prepared by adding extra nutrients to a medium
called nutrient agar.
Blood Agar Types
✓Blood agar plates (BAP)
>Contains mammalian blood, typically at
aconcentration of 5–10%
>Used isolate fastidious organisms and detect
hemolytic activity (Neisseria and Streptococcus).
✓Chocolate agar (CHOC)
>blood cells have been lysed by heating the cells
to 56° C.
14. > Used for growing fastidious (fussy)
respiratorybacteria, such asHaemophilus
influenzae
15. ✓Various categories of media are not
mutually exclusive.
✓Ex: blood agar is enriched and
differential
✓MacConkey agar and MSA are
selective and differential
✓PEA and CNA are enriched and
selective
✓Thayer-Martin and Martin-Lewis are
highly enriched and highly selective
✓Thioglycollate broth (THIO) is a liquid
16.
17. Fungal Media
✓Sabouraud agar
>Sabouraud agar is used to culture
fungi andyhas a low pH that inhibits the
growth of most bacteria; also contains the
antibiotic gentamicin to specifically inhibit
the growth of Gram-negative bacteria.
✓Hay infusion agar
>Specific for the culturing of slime
molds(though not technically fungi).
✓Potato dextrose agar
> PDA is used to culture of certain
types of fungi.
18. Preparation of CM
✓Nutrient Broth
>Dissolve 8 g of NB powder in 1000 ml of distilled
water in an Erlenmeyer flask. Mix and heat over the
magnetic stirrer until the medium becomes clear or
transparent.
>Dispense 8 ml of the medium into sterile test tubes.
>Immediately stopper the tubes completely.
>Sterilize in the autoclave at 15 psi, 121 C for 15mins.
Nutrient Agar
>Dissolve 28 g of NA powder in 1000 l of distilled
water in an Erlenmeyer flask. Mix andheat over the
magnetic stirrer until themedium becomes clear or
transparent.
19. Dispensing the CM
✓NA plate
>Lay out several sterile Petri dishes on the table
with the cover partially open and dispense the
medium inside and inoculating hood.
>Dispense the NA medium (30 ml) and allow 5-
10 minutes to elapse before completely covering
the dish to avoid contamination.
>When the medium is solidified, label the NA
plate.Wrap and label the plate.
20. NA slant
>Dispense 8 ml of the medium into sterile
test tubes using pipette or syringe.
>Cover the tube partially with sterile cotton
plug or screw cap and allow the agar
medium to harden in an incline position on
an agar slant rack.
>Stopper the tube completely when the
medium has solidified. Label the upper
portion of the test tube slant.
>Sterilize in the autoclave at 15 psi, 121 C
for15 mins.
21. Inoculation of Culture Media
✓Inoculation- adding a portion
of thesπpecimen to the medium.
✓Involves the use of sterile
inoculating loop to apply a
portion of the specimen to the
surface of the medium; a
process commonly referred to
as “streaking”.
