culture media Flashcards
(5 cards)
what are control strains/ standard cultures
well identified species of bacteria that exhibit typical microscopic, macroscopic and biochemical characteristics. these are considered as standards for comparing other strains. each species has numerous designations by different organizations eg. by the American Type Culture Collection E.coli is ATCC 11775
what is a wild culture
culture made from speciment taken from patients, therefore may not have grown under typical conditions, may not exhibit typical characteristics and may be used to check the selectivity of media
how is blood agar prepared
regular nutrient agar is prepared on two speerate days. on the first day after cooling a first layer is poured, on the second day once medium has cooled to around 45 degrees, the horse blood is heated to around 35 degrees and 7 % defribrinated horse blood is added aspectically. (7% of the total mixture eg 70mls for each litre.
prep of chocolate agar
prepare the blood agar base
autoclave at 121 for 15 minutes
let cool in water bath at 80 degrees
add 7% defibrinated horse blood aseptically
leave at 80 degrees for 5-10 minutes
cool to 50 degrees
what is selective media
media used for the recovery of specific organisms that may be present in a mixture of other organisms. they prevent the growth of commensals
