4 - Toxin Mediated Food Poisoning

Question 1

What bacteria is this and what agar? And Exception

Answer 1

Staph Aureus
Nutrient Agar: opaque, golden yellow colonies

Exception: Staph Epidermidis forms whitish opaque colonies

Question 2

What bacteria is this and what agar?

Answer 2

Staph Aureus
Blood Agar with Beta type of hemolysis with clear zone around colonies

Question 3

What bacteria is this and what agar? Also, what is the exception?

Answer 3

Staph Aureus
Mannitol Salt Agar: Yellow colonies due to fermentation of mannitol sugar and growth in high salt concentration

Exception: Staph Epidermidis doesn’t ferment Mannitol

Question 4

What bacteria is this and what are its features?

Answer 4

Bacillus Cereus: Gram +, aerobic, spore-bearing bacilli

Question 5

What bacteria is this and what are its features?

Answer 5

Clostridium Perfringes: G + bacilli with sub-terminal spores, non-motile, ANAEROBIC

Question 6

What is this and what bacteria is it?

Answer 6

Nagler’s Reaction demonstrated on Egg Yolk Agar: Tests presence of alpha-toxin (lecithinase) that’s produced by perfringens
Clostridium Perfringens

Question 7

What bacteria is this and what are its features? Extra feature

Answer 7

Gram stain of Clostridium Botulinum: Anerobic, spore-forming, gram positive bacilli

Gram stain looks G-, but is G+