Organism responsible for catheter predisposed UTI is: September 2005
**Core Concept**
The question is testing the student's knowledge of the common causative agents of urinary tract infections (UTIs), particularly those associated with catheter use. The correct answer requires an understanding of the pathogenesis of UTIs and the role of certain organisms in catheter-associated UTIs.
**Why the Correct Answer is Right**
Catheter-associated UTIs are often caused by bacteria that can form biofilms on the surface of the catheter. **Proteus mirabilis** is a gram-negative rod that is commonly implicated in these infections. It can form biofilms and adhere to the catheter surface, leading to colonization and subsequent infection. This organism is also capable of producing urease, which can contribute to the development of urinary tract stones and worsen the infection.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because **Escherichia coli (E. coli)** is a common cause of UTIs, but it is not the most common cause of catheter-associated UTIs. While **E. coli** can cause UTIs, it is not as strongly associated with catheter use as **Proteus mirabilis**.
* **Option B:** This option is incorrect because **Klebsiella pneumoniae** is a gram-negative rod that can cause UTIs, but it is not the most common cause of catheter-associated UTIs.
* **Option D:** This option is incorrect because **Staphylococcus aureus** is a gram-positive cocci that can cause UTIs, but it is not the most common cause of catheter-associated UTIs.
**Clinical Pearl / High-Yield Fact**
It's essential to note that catheter-associated UTIs are often resistant to antibiotics and may require specific treatment strategies. The use of antibiotic-coated catheters and the implementation of good catheter care practices can help reduce the risk of these infections.
**Correct Answer:** C. **Proteus mirabilis**