In: Biology
TSI test:
TSI test, differentiates fermentation capabilities of carbohydrates sources. It differentiates enteric bacteria, mainly faculative mainly enteric bacteria.
Results indicated as:
TSI results:
K= Alkaline
A = Acid
NC = No change
representation |
interpretation |
K/K or red/red |
No sugar fermentation |
K/A or red/yellow |
Only glucose fermentation |
A/A or yellow/yellow |
Fermentation of glucose and lactose/sucrose sugars |
NC/NC |
Less growth, no fermentation or peptone utilization. |
K/ NC |
No sugar fermentation, superficial utilization of peptone. |
A/ NC |
Superficial growth with fermentation. |
Gas production = bubble/crack
H2S Production= Black coloration/ deposit
Thus, fermentation only on the slant region may be due to contamination and is not reliable to state result for facultative bacteria or enteric bacteria differentiation.