Bacteriological Culture Media & Cultivation of Bacteria Flashcards
What is Culture Media used for? (4)
1) increase number of bacteria
2) differentiate between bacteria
3) select for certain bacteria and suppress others
4) grow bacteria
What is the purpose of culturing?
1) Isolating
2) properties of bacteria
3) create antigens of lab use
4) typing w/ bacteriophages and bacteriocins susceptibility
5) test antibiotic sensitivity
6) estimate viable counts
What is an important characteristic of Agar and where does it come from
Agar comes from seaweed Gelidium
it is a solidifying agent for media because it solidifies at 50 C and melts at 100C. its is also nontoxic for growth of bacteria
growth media is based on what bacterial metabolism
1) pH
2) cultures oxidation and reduction potential
3) gaseous requirements
4) Oxygen and CO2 and other gases
Define 3 different types of classification for media
1) consistency (3)
2) nutritional components (2)
3) function or property (8)
what is a benefit of liquid media
proliferates bacteria
what is a benefit of semi-solid media
clot like, determines motility
what is a benefit of solid media
isolating and culturing
What is Blood Agar and what does it contains
contains defibrinated blood
used for culture of fastidious org. (streptococcus pyogenes) that lyses RBC
What is Chocolate Agar (heated blood agar) and what does it contain
similar to blood agar, used to culture some fastidious bacteria ( Neisseria gonorrhoaea, Streptococcus pneumonia and Haemophiles influenza)
has defibrinated horse/sheep blood to medium after sterilization and cooling to 80C. then heated over bunsen burner flaim until it turns chocolate brown
Nutrient Agar (General purpose)
supports growth of variety of bacteria. used to get pure cultures
CLED Plate (differential)
Cystein Lactose Electrolyte Deficient
lacking in electrolytes
used for cultivation of uropathogens (bacteria that cause UTI)
absence of electrolytes prevents growth of swarming bacteria
