TSI tubes

Triple Sugar Iron


Introduction
Principles/Images
Protocol
Recipe
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Microbe Library

Principles/Images

Based on carbohydrate utilization, a TSIA slant can be interpretted in one of four ways:

  • Alkaline over acid: only glucose metabolized
  • Acid over acid: glucose metabolized and lactose and/or sucrose also metrabolized
  • Alkaline over akaline: glucose, lactose, and sucrose are not metabolized, peptones used aerobically and anerobically
  • Alkaline over no change: glucose, lactose, and sucrose are not metabolized, peptones used aerobically
TSIA tube
TSIA slant  
Lactose and/or Sucrose
Fermenter

 

 Gas production   Lactose and/or Sucrose
Fermenter with H2S

 

TSIA tube   TSIA tube  
Glucose Fermenter   Glucose Fermenter and
H2S positive
  Nonfermenter

Images © Don Lehman