Bactericidal antibiotic is:

Question

Accepted Answer

Ofloxacin is the correct answer as a bactericidal antibiotic. Bactericidal antibiotics are those that kill bacteria directly, as opposed to bacteriostatic antibiotics, which only inhibit the growth and reproduction of bacteria.

1. **Why Ofloxacin (Option 2) is Correct:**
   - Ofloxacin is a fluoroquinolone antibiotic that works by inhibiting bacterial DNA gyrase and topoisomerase IV. These enzymes are crucial for bacterial DNA replication, transcription, repair, and recombination. By inhibiting these enzymes, Ofloxacin causes bacterial cell death, making it a bactericidal antibiotic. This mechanism of action is effective against a broad range of Gram-positive and Gram-negative bacteria.

2. **Why the Other Options are Incorrect:**
   - **Erythromycin (Option 1):** Erythromycin is a macrolide antibiotic that is primarily bacteriostatic. It works by binding to the 50S ribosomal subunit of bacteria, inhibiting protein synthesis. This action prevents bacteria from growing and reproducing but does not directly kill them, which is why it is not considered bactericidal.
   
   - **Tetracycline (Option 3):** Tetracycline is a bacteriostatic antibiotic that inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit. This prevents the addition of amino acids to the growing peptide chain, thereby inhibiting bacterial growth and reproduction rather than killing the bacteria outright.
   
   - **Chloramphenicol (Option 4):** Chloramphenicol is also primarily bacteriostatic. It inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, preventing peptide bond formation. While it can be bactericidal against certain organisms in high concentrations or specific conditions, it is generally not classified as a bactericidal antibiotic.

In summary, Ofloxacin is the correct choice as a bactericidal antibiotic due to its mechanism of action that directly leads to bacterial cell death, distinguishing it from the other options, which are primarily bacteriostatic.