Unit 3: Common Culture Media: Broths

Question 1

when are broth media used (3)

Answer 1

• growth of even small # is significant (sterile body fluids)
• anaerobic cultures from sterile sites
• culture where pathogens have low infecting dose + heavy load of norm flora (enrichment broth)

Question 2

why Brain heart infusion with fildes included in CSF specimen set up

Answer 2

BHIB is clear easier to detect turbidity. Fildes provides X/V factors enhance fastidious org. has no selective properties

Question 3

e.g. of species grown on BHIB

Answer 3

fastidious Haemophilus influenza associated w/meningitis

Question 4

purpose of 0.075% agar, and reducing agents in THIO broth

Answer 4

little bit of agar makes it viscous, reducing O2 diffusion into media. lower Eh necessary for anaerobic

Question 5

classification of Thioglycollate broth and why

Answer 5

enriched- glucose, vit K, hemin and thioglycollate. enhances recovery of anaerobes

Question 6

what are the reducing agents in THIO broth

Answer 6

sodium thioglycoolate plus L-cystein and Na SO4

Question 7

classification of BHIB and why

Answer 7

enriched- brain and heart tissue with proteins. Files added to supply X and V factors for fastidious org