How do antibiotics kill or stop the growth of bacteria?

Antibiotics function through several distinct mechanisms to either destroy bacteria or inhibit their ability to grow and reproduce.12

Mechanisms of Action

• Inhibiting Cell Wall Synthesis: Agents such as β-lactam antibiotics interfere with the assembly or cross-linking of the bacterial cell wall. This structural compromise causes the bacterium to lose its shape and eventually die.12
• Disrupting Protein Synthesis: Many antibiotics target bacterial ribosomes. By binding to these structures, they prevent the bacteria from synthesizing the proteins necessary for survival and reproduction.12
• Damaging the Cell Membrane: Certain antibiotics, like polymyxin, bind to phospholipids in the bacterial cell membrane. This disrupts the membrane's function as a selective barrier, causing essential cellular contents to leak out and leading to cell death.12
• Blocking Metabolic Pathways: Sulfonamides act as competitive inhibitors that block the production of folic acid, which is essential for nucleic acid synthesis. This process typically stops bacterial growth rather than killing the organism directly.12
• Interfering with RNA Synthesis: Antibiotics like rifampin bind to bacterial enzymes to prevent the production of RNA, effectively halting essential cellular processes.12