Which statement best describes the mechanism by which chlorhexidine disrupts microbial membranes?

Which statement best describes the mechanism by which chlorhexidine disrupts microbial membranes?

• A. Inhibits DNA replication
• B. Disrupts cell membranes by binding to negatively charged molecules
• C. Inhibits protein synthesis by binding 50S
• D. Inhibits folate synthesis

Answer: (B)

Chlorhexidine acts by a membrane-targeting mechanism. It is a positively charged compound that binds to negatively charged components of the microbial cell envelope, such as phospholipids and teichoic acids. This electrostatic attraction disrupts the integrity of the cell membrane, increases permeability, and causes leakage of ions and other cytoplasmic contents, leading to cell death. This membrane-disruption action explains its rapid antiseptic effect across a broad range of microbes. By contrast, the other options describe mechanisms that target intracellular processes—DNA replication, protein synthesis at the 50S ribosomal subunit, or folate synthesis—which are not how chlorhexidine primarily works.

Chlorhexidine acts by a membrane-targeting mechanism. It is a positively charged compound that binds to negatively charged components of the microbial cell envelope, such as phospholipids and teichoic acids. This electrostatic attraction disrupts the integrity of the cell membrane, increases permeability, and causes leakage of ions and other cytoplasmic contents, leading to cell death. This membrane-disruption action explains its rapid antiseptic effect across a broad range of microbes. By contrast, the other options describe mechanisms that target intracellular processes—DNA replication, protein synthesis at the 50S ribosomal subunit, or folate synthesis—which are not how chlorhexidine primarily works.