Download Theme J03: Cultivation

Theme J03
Theme J03: Cultivation
Task 1: Characterisation of media and their production
Task 1a: Most important media in medical microbiology
Look at given media and write here the type of medium according to explanation given by your
teacher. Do not forgot to write, whether the medium is solid or liquid and whether it is in a Petri
dish or in a test tube.
Name of medium Liquid/solid
Colour
Type of medium Used for
Petri dish/test t.
(selective, …)
bacteria:
Task 1b: Production of blood agar.
Look at the video. Describe the procedure on the opposite side of this sheet.
Task 2: Influence of physical and chemical conditions on the bacterial growth
Task 2a: Influence to oxygen
Five strains (J, K, L, M, N) were cultured on agar plates in four types of conditions: a) normal
athmosphere b) elevated CO2 concentration c) decreased oxygen conc. d) no oxygen at all
Write „growing“, „not growing“, assess, which strain is strictly aerobic, facultatively anaerobic,
strictly anaerobic, microaerophilic, capnophilic
normal air
elevated
traces of
no oxygen
conclusion
CO2
oxygen only
Task 2b: Influece of salts and antibiotics
You can see three strains on various types of media. Describe the presence/absence of growth
(GROWS – DOES NOT GROW)
Strain
Blood agar
BA + NaCl
BA + NaCl
Slanetz
BA with
(BA)
(6,5 %)
(10 %)
Bartley agar amicacine
E – enterococcus
SR – streptoccus
ST – staphylococ.
Name _________________________ Group______ Gen. med. – stomatology
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Theme J03
Task 2c: Influence of temperature
Like the previous, only with the same medium, but different temperature:
Strain
4 °C
37 °C
42 °C
Task 3: Properties of the two most common diagnostic and selective-diagnostic
media
Task 3a: Blood agar – viridation and hemolysis
Describe haemolytical properties of four strains on blood agar. Read against light.
Streptococcus pyogenes
Streptococcus agalactiae
Streptococcus pneumoniae
Enterococcus faecalis
Task 3b: Endo agar – presence/absence of growth, lactose fermentation
Describe growth/no growth, and changes of the medium surrounding the colonies.
Staphylococcus epidermidis
Escherichia coli
Salmonella Enteritidis
Task 4: Description of morphologic characteristics of colonies
Describe three strains of bacteria
Strain
Size
Colour
Shape
Profile
Surface
Edges
Translucency
Consistency
Odour
Surroundings
Strain
Strain
Task 5: Inoculation of samples and streins on solid media
Task 5a: Inoculation of a swab
Task 5b: Inoculatiob of a strain
Inuculate a swab (a) and a strain (b) on the medium. Draw your result to the opposite side of this
sheet.
Check-up questions:
(Use another sheet of paper or another side of this one for answers)
1. Parafin oil is usually poured on VL-broth when used for bacteria cultivation. Why?
2. Why do we add the red blood cells after (and not before) the decrease of temperature of the agar medium?
3. Why, at bacteriological media preparing, agar is used rather then gelose?
4. Microaerophilia and capnophilia: is it the same?
5. Is the ability of staphylococci to grow at high NaCl concentracions connected with its adaptation to the host
organism?
6. Which growth characteristics are not recognizable using your eye? And which one needs a loop contact with a
colony?
7. Why is it so important to obtain individual colonies when we culture bacteria on solid media?
8. Blood agar is usually made of „basis for blood agar“ (approximatelly, this one is equivalent to nutrient agar) and
defibrinated sheep blood. Is it possible to add sheep blod to other bases than the one listed above?
Name _________________________ Group______ Gen. med. – stomatology
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