Action of Antibiotics

Action of Antibiotics

Definition and Function

• Antibiotics are antimicrobial drugs used to treat bacterial infections.
• They work by disrupting essential processes or structures in the bacterial cell.
• Given their specific action, antibiotics are not effective against viral, fungal or other non-bacterial infections.

Types of Antibiotics based on Action

Bactericidal Antibiotics

• Bactericidal antibiotics kill bacteria directly.
• They typically target bacterial cell structure, including the cell wall or cell membrane.

Bacteriostatic Antibiotics

• Bacteriostatic antibiotics inhibit bacterial growth and reproduction.
• They interfere with processes such as protein synthesis, DNA replication, or metabolic pathways.

Specific Actions of Antibiotics

Disruption of Cell Wall Synthesis

• Some antibiotics, such as penicillin, interrupt the synthesis of peptidoglycan, a key component of the bacterial cell wall.
• This weakens the cell wall, which can lead to cell lysis.

Inhibition of Protein Synthesis

• Other antibiotics, like tetracyclines and macrolides, hamper bacterial protein synthesis.
• These antibiotics bind to the bacterial ribosomes, blocking the translation process.

Interference with Nucleic Acid Synthesis

• Certain antibiotics, such as quinolones, interfere with DNA replication in bacteria.
• They inhibit the bacterial DNA gyrase or topoisomerase IV enzyme, disrupting DNA supercoiling and replication.

Disruption of Metabolic Pathways

• Antibiotics like sulfonamides and trimethoprim impair metabolic pathways in bacteria.
• These drugs act as competitive inhibitors, blocking the utilization of vital nutrients necessary for bacterial survival.

Understanding how antibiotics work enables us recognise their limitations, strengthens our knowledge on pathogen control and contributes to the responsible use of these essential drugs to limit antibiotic resistance.