## **Core Concept**
Antipseudomonal penicillins are a class of β-lactam antibiotics that are effective against *Pseudomonas aeruginosa*, a type of Gram-negative bacteria. These antibiotics are crucial in treating infections caused by this organism, particularly in patients with compromised immune systems or those with cystic fibrosis. The primary antipseudomonal penicillins include piperacillin and ticarcillin.

## **Why the Correct Answer is Right**
The correct answer, **. Piperacillin**, is a broad-spectrum antipseudomonal penicillin. It works by inhibiting bacterial cell wall synthesis through binding to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, resulting in the disruption of the cell wall and ultimately leading to cell lysis and death. Piperacillin has a broad spectrum of activity, including effectiveness against *Pseudomonas aeruginosa*, *Escherichia coli*, *Klebsiella pneumoniae*, and various other Gram-positive and Gram-negative bacteria.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is blank and does not provide a valid antibiotic name for evaluation.
- **Option B:** This option is also blank and does not provide a valid antibiotic name for evaluation.
- **Option D:** This option is blank as well and lacks a valid antibiotic name for assessment.

## **Clinical Pearl / High-Yield Fact**
A key clinical point to remember is that piperacillin is often combined with a β-lactamase inhibitor, such as tazobactam, to broaden its spectrum of activity and protect it from degradation by β-lactamases. This combination, known as piperacillin/tazobactam, is commonly used in clinical practice for its broad-spectrum efficacy, including against *Pseudomonas aeruginosa*.

## **Correct Answer: C. Piperacillin**