Salmonella typhi can be isolated at different times from
**Core Concept**
Salmonella Typhi is a Gram-negative bacterium that causes typhoid fever. The bacterium can be isolated from various body sites at different times during the course of the disease.
**Why the Correct Answer is Right**
The bacterium can be isolated from stool during the first week of illness, from blood during the second week, and from urine and stool during the third week. This is due to the fact that the bacterium initially colonizes the small intestine, then invades the bloodstream, and eventually localizes in the gallbladder and urine-producing organs. The bacterium can be isolated from stool throughout the illness, as it is continuously shed in the feces.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.
**Clinical Pearl / High-Yield Fact**
It's essential to note that Salmonella Typhi can be isolated from stool even after the patient has recovered, as the bacterium can persist in the gallbladder for a long time.
**Correct Answer:** C.