Which organism can be isolated from stool & sputum-
**Core Concept**
The question is testing the identification of an organism that can be isolated from both stool and sputum, indicating its presence in the respiratory and gastrointestinal tracts. This organism is likely a common pathogen that can cause infections in both these body systems.
**Why the Correct Answer is Right**
The correct answer is **Klebsiella pneumoniae**. This bacterium can cause infections in the lungs (respiratory tract) and intestines (gastrointestinal tract), and can be isolated from both sputum and stool samples. Klebsiella pneumoniae produces capsular polysaccharides that confer resistance to phagocytosis, allowing it to establish infection. It also produces enzymes such as beta-lactamases that confer resistance to antibiotics.
**Why Each Wrong Option is Incorrect**
* **Option A:** Staphylococcus aureus is primarily a skin and soft tissue pathogen, and is not typically isolated from stool.
* **Option B:** Escherichia coli is a common gut commensal, but it is not typically isolated from sputum unless it has caused a urinary tract infection that has ascended to the kidneys.
* **Option C:** Pseudomonas aeruginosa is a common respiratory pathogen, but it is not typically isolated from stool.
**Clinical Pearl / High-Yield Fact**
Klebsiella pneumoniae is a notorious cause of hospital-acquired infections, particularly in patients with compromised immune systems. It is often resistant to multiple antibiotics, making treatment challenging.
**Correct Answer:** C. Klebsiella pneumoniae