Amphenicol

A class of broad-spectrum antibiotics

Overview

Amphenicols are a class of broad-spectrum antibiotics that are effective against a wide range of bacteria. They are particularly known for their ability to inhibit bacterial protein synthesis by binding to the 50S subunit of the bacterial ribosome. This class includes well-known antibiotics such as chloramphenicol, thiamphenicol, and florfenicol.

Mechanism of Action

Amphenicols exert their antibacterial effects by interfering with the peptidyl transferase activity of the bacterial ribosome. By binding to the 50S ribosomal subunit, they prevent the formation of peptide bonds during protein synthesis, thereby inhibiting bacterial growth and reproduction. This mechanism is similar to that of other antibiotics such as macrolides and lincosamides, but amphenicols have a distinct binding site.

Clinical Uses

Amphenicols are used to treat a variety of infections, particularly those caused by Gram-positive and Gram-negative bacteria.

Chloramphenicol

Chloramphenicol is used in the treatment of serious infections such as meningitis, typhoid fever, and rickettsial infections. Due to its potential for serious side effects, including aplastic anemia, its use is generally reserved for severe infections where other antibiotics are ineffective.

Thiamphenicol

Thiamphenicol is a derivative of chloramphenicol with a similar spectrum of activity but is less likely to cause aplastic anemia. It is used in some countries for the treatment of respiratory tract infections and sexually transmitted infections.

Florfenicol

Florfenicol is primarily used in veterinary medicine. It is effective against a range of bacterial infections in animals, including bovine respiratory disease and swine respiratory disease.

Side Effects

The use of amphenicols can be associated with several side effects. The most serious is the risk of bone marrow suppression, which can lead to aplastic anemia. Other side effects may include gastrointestinal disturbances, allergic reactions, and neurological effects.

Resistance

Bacterial resistance to amphenicols can occur through various mechanisms, including the production of chloramphenicol acetyltransferase, which inactivates the drug, and mutations in the ribosomal binding site. The spread of resistant strains is a significant concern in both human and veterinary medicine.

Related Pages

• Antibiotic resistance
• Protein synthesis inhibitors
• Broad-spectrum antibiotics

Images

Chemical structure of florfenicol