A girl complained of pain abdomen with the passage of foul smelling stool. The stool doesn’t wash away easily. There is a history of swimming in bad water. What could be the causative organism?
**Core Concept**
The patient's symptoms suggest an intestinal infection caused by a pathogen that is commonly associated with contaminated water exposure. The clinical presentation of foul-smelling stool and abdominal pain, along with a history of swimming in bad water, points towards a specific type of bacterial infection.
**Why the Correct Answer is Right**
The causative organism in this scenario is likely to be *Vibrio cholerae*, which is a Gram-negative, facultatively anaerobic bacterium. *Vibrio cholerae* is a waterborne pathogen that can cause cholera, a diarrheal disease characterized by the passage of large amounts of watery stool (often referred to as "rice-water stool") that does not wash away easily. The foul smell and the patient's exposure to contaminated water make this organism a likely candidate.
**Why Each Wrong Option is Incorrect**
* **Option A:** *Salmonella* species are also waterborne pathogens that can cause gastrointestinal infections, but they typically cause a more severe inflammatory response and are associated with a wider range of symptoms, including fever and abdominal cramps.
* **Option B:** *Escherichia coli* (E. coli) is a common cause of diarrheal disease, but it is more often associated with foodborne transmission and typically causes a milder infection than *Vibrio cholerae*.
* **Option D:** *Shigella* species are also waterborne pathogens that can cause dysentery, but they typically cause a more severe inflammatory response and are associated with a wider range of symptoms, including fever and abdominal cramps.
**Clinical Pearl / High-Yield Fact**
When considering the diagnosis of cholera, remember that the "rice-water stool" is a characteristic feature of the disease, and the presence of a foul smell and a history of exposure to contaminated water can help to support the diagnosis.
**Correct Answer:** C. *Vibrio cholerae*.