This article will definitely make you understand about TSI media & it's result.

1. TSI MEDIA
Kaushik Sen
MLT,Dept of Microbiology, ESIC
MED. COLLEGE

2. •The Triple Sugar Iron (TSI) test is
a microbiological test roughly named
for its ability to test a microorganism's
ability to ferment sugars and to
produce hydrogen sulfide.[1] It is often
used to differentiate enteric bacteria
including Salmonella and Shigella.

3. Uninoculated
TSI Media

6. Straight wire

7. Uninoculated
TSI Media

8. HOW TO INOCULATE TSI
MEDIA?

9. • With a straight inoculation needle, touch
the top of a well-isolated colony.
• Inoculate TSI by first stabbing through
the center of the medium to the bottom
of the tube and then streaking the surface
of the agar slant.
• Leave the cap on loosely and incubate the
tube at 35°-37°C in ambient air for 18 to
24 hours.
• Examine the reaction of medium.

10. Result after overnight incubation at 37

11. SLANT/BUTT
A/A+ GAS(CO2)
• Glucose, Lactose
& / or sucrose is
fermented
• Bubbles or cracks
present - gas
production
K– Alkaline
A-- Acidic

12. SLANT/BUTT
K/A (no gas)
• Only
Glucose is
fermented
K– Alkaline
A-- Acidic

13. SLANT/BUTT
K/K (no gas)
• No sugar is
fermented
K– Alkaline
A-- Acidic

14. SLANT/BUTT
K/A+ GAS(H2S)
• Only Glucose is
fermented
• Black precipitate
present - H2S gas
production
K– Alkaline
A-- Acidic

15. SLANT/BUTT
A/A+ GAS(CO2+H2S)
• Glucose, Lactose &/
or Sucrose are
fermented
• Butt region turns
Black due to
Hydrogen sulphide
K– Alkaline
A-- Acidic

18. TSI RESULT FOR DIFFERENT
BACTERIA

19. Y
=
yellow
=
Acid
R=red=
Alkaline

20. TSI agar slant results: (from left) preinoculated (as control), P. aeruginosa, E.
coli, Salmonella Typhimurium, Shigella flexneri

21. TSI RESULT

23. END