Identify the incorrect statement with respect to antibiotics.

Penicillin is bacteriostatic antibiotic

The correct answer is option 3. Penicillin is bacteriostatic antibiotic.

Let us delve into each statement:

1. Arsphenamine is toxic to humans:

This statement is correct. Arsphenamine, also known as Salvarsan, was one of the first synthetic antibiotics used to treat syphilis. While it was effective against the bacterium causing syphilis, it also exhibited significant toxicity to humans. Due to its toxicity and the availability of safer alternatives, such as penicillin, arsphenamine is no longer used in clinical practice.

2. Ampicillin is a broad-spectrum antibiotic:

This statement is correct. Ampicillin is a broad-spectrum antibiotic belonging to the penicillin group. It is effective against a wide range of bacteria, including both Gram-positive and Gram-negative bacteria. Ampicillin works by inhibiting bacterial cell wall synthesis, leading to cell death.

3. Penicillin is a bacteriostatic antibiotic:

This statement is incorrect. Penicillin is actually a bactericidal antibiotic, meaning it kills bacteria rather than merely inhibiting their growth. Penicillin interferes with the synthesis of bacterial cell walls, weakening them and leading to bacterial cell lysis and death. It does not merely inhibit bacterial growth but actively destroys bacteria.

4. Sulphanilamide has antibacterial properties:

This statement is correct. Sulphanilamide, also known as sulfanilamide, is an antibacterial agent belonging to the sulfa drug class. It inhibits the growth of bacteria by interfering with their folic acid synthesis, which is essential for bacterial growth and reproduction. As a result, sulphanilamide has antibacterial properties and is used to treat various bacterial infections.

Summary:

Arsphenamine: Effective against syphilis but toxic to humans.

Ampicillin: Broad-spectrum antibiotic effective against a wide range of bacteria.

Penicillin: Bactericidal antibiotic that kills bacteria by interfering with cell wall synthesis.

Sulphanilamide: Antibacterial agent inhibiting bacterial growth by interfering with folic acid synthesis