Final answer:
The TSI test is used to differentiate bacteria based on their sugar fermentation abilities. Klebsiella pneumoniae typically produces a positive TSI reaction, fermenting sugars and producing H₂S gas.
Step-by-step explanation:
The TSI (Triple Sugar Iron) test is a diagnostic tool used to differentiate between different types of bacteria based on their ability to ferment sugars and produce certain byproducts. In this case, the question is referring to the TSI reaction of the bacterium Klebsiella pneumoniae. The TSI reaction involves the fermentation of sugars (such as lactose and sucrose) and the production of hydrogen sulfide (H₂S) gas.
In the TSI test, a slant and butt of a medium containing sugars and other nutrients are inoculated with the bacterial sample. The slant is an aerobic environment, while the butt is anaerobic. If the bacterium is able to ferment the sugars, it will produce acid, causing the slant to turn yellow (A/A) or alkaline, causing it to turn red (K/A). H₂S gas production is detected as a blackening of the medium.
In the case of Klebsiella pneumoniae, it typically produces a positive TSI reaction, meaning it ferments both lactose and sucrose, resulting in the acidification of the slant (yellow color) and the production of H₂S gas (blackening of the medium). Therefore, a typical TSI reaction for Klebsiella pneumoniae would be A/A H₂S+.