Which of these is true of E. Coli
**Core Concept**
E. Coli is a gram-negative, rod-shaped bacterium that is commonly found in the human gut. It plays a crucial role in the normal flora of the gastrointestinal tract, but certain pathogenic strains can cause severe infections.
**Why the Correct Answer is Right**
The correct answer is related to the fact that E. Coli is a facultative anaerobe, meaning it can grow in the presence or absence of oxygen. This ability allows it to thrive in various environments, including the gut, where oxygen levels can fluctuate. The enzyme lactate dehydrogenase helps E. Coli to survive in low-oxygen conditions by converting pyruvate to lactate, which is then used as an energy source.
**Why Each Wrong Option is Incorrect**
* **Option A:** E. Coli is actually a gram-negative bacterium, not gram-positive. This distinction is important in understanding its cell wall structure and the mechanisms of antibiotic resistance.
* **Option B:** While E. Coli is a common cause of urinary tract infections (UTIs), it is not the only causative agent. Other bacteria like Klebsiella pneumoniae and Pseudomonas aeruginosa can also cause UTIs.
* **Option C:** E. Coli can produce enterotoxins, which cause diarrhea and other gastrointestinal symptoms, but it is not typically associated with the production of botulinum toxin.
**Clinical Pearl / High-Yield Fact**
E. Coli is a significant cause of antibiotic resistance, particularly in hospitals, where the overuse and misuse of antibiotics have led to the emergence of multidrug-resistant strains.
**Correct Answer:** C. E. Coli can produce enterotoxins, which cause diarrhea and other gastrointestinal symptoms.