Methods Of Identification Culture Method Flashcards
provides the appropriate
biochemical and biophysical environment for microbial growth
CULTURE MEDIA
COLONY
Types:
• Mucoid colony
• Smooth colony
• Rough colony
Culture
•Types:
pure, mixed, stock
TYPES OF CULTURE MEDIA
Based on:
• Physical Form / Consistency
• Composition
• Function / Purpose
• Distribution
Physical Form:
• water- based
• broth, milk, infusion
LIQUID MEDIA
Liquid media
Positive growth
dispersed
cloudy
turbidity
particulate appearance
Physical Form:
SEMI - SOLID MEDIA
with solidifying agent ______
• detects bacterial motility
0.3 - 0.5% Agar
Semi-Solid
Examples:
@___________
@_____= detects H2S& indole production
Motility test medium
SIM
Physical Form:
SOLID MEDIA
• allows growth of discrete colonies
@_______ agar
1-5% Agar
SOLID MEDIA
LIQUEFIABLE
NON - LIQUEFIABLE
• NA, MacConkey
• Middlebrook 7H11
•Lowenstein - Jensen media
Composition:
• chemically defined
SYNTHETIC MEDIA
Composition:
• complex media
NON-SYNTHETIC MEDIA
• at least one of the ingredients is not chemically defined
• for cultivation of bacterial pathogens & fastidious bacteria
NON-SYNTHETIC MEDIA
Anaerobic Growth
Anaerobic bacteria requires:
• Low oxygen content
• Reduced oxidation-reduction potential
• Extra nutrients
Anaerobic media examples
•Anaerobic PEA
•Anaerobic KV Thioglycollate broth
•Robertson Cooked Meat = bullock heart meat
• maintains viability of bacteria and slows rate of reproduction
Transport Media
Transport media purpose
Purpose:
1. Prevents drying / desiccation of specimen
2. Inhibit overgrowth of unwanted bacteria
TRANSPORT MEDIA
STUART’S (1954)
AMIES (1965)
CARY BLAIR (1964)
BUFFERED GLYCEROL SALINE
• Maintains original state of specimen
• with charcoal-impregnated swabs & glycerophosphate in medium
STUART’S (1954)
• Replace glycerophosphate w/ balanced salt soln
• charcoal is incorporated into medium
AMIES (1965)
• pH increased from 7.4 to 8.4
• No charcoal
• Recommended for fecal specimens suspicious for Campylobacter sp
CARY BLAIR (1964)
• Good for mailing fecal specimens
• High ph to favor fecal pathogens
• Not for transport of fecal specimens suspected to be
Campylobacter sp (+)
BUFFERED GLYCEROL SALINE
Functional Type:
• for the assay of vitamins, amino acids and antimicrobial agents.
• to monitor the effects of the administration of certain antimicrobial drugs.
Assay Media
Assay Media example
Mueller Hinton Agar
Functional Type:
• Used by industrial and environmental
microbiologists to count the number of organisms in milk, water, food, soil and other samples.
Enumeration Media
Potato-Dextrose Agar
Enumeration media
Measurement of Cell Numbers
1.Direct microscopic counts
2. Electronic counting chambers
3. Indirect viable cell counts
Distribution:
TUBED
• Butt
• Slant
•Slant/Butt
METHODS OF OBTAINING PURE
CULTURE
A. STREAK PLATE
B. POUR PLATE
C. SELECTIVE METHOD
D. ANIMAL INOCULATION
PLATED MEDIA
QUADRANT STREAK
CONTINUOUS STREAK
RADIANT STREAK
Preserving Bacterial Cultures
• Deep-freezing:
-50° to -95° C
Preserving Bacterial Cultures
• Lyophilization:
Frozen (-54° to -72° C)
then vacuum-dehydrated