Gram-positive bacterial cytoplasmic membrane

The Gram-positive bacterial cytoplasmic membrane is a vital phospholipid bilayer that serves as the primary barrier between the bacterial cytoplasm and the external environment [Strahl & Hamoen, 2010]. It plays a critical role in maintaining cellular homeostasis, facilitating nutrient transport, and hosting essential processes such as oxidative phosphorylation and the synthesis of the peptidoglycan cell wall [Heidary et al., 2022]. In Gram-positive bacteria, this membrane is characterized by a high content of negatively charged phospholipids like phosphatidylglycerol, which makes it a selective target for cationic antimicrobial peptides and lipopeptide antibiotics [Zhanel et al., 2010]. Drugs like daptomycin interact with this membrane in a calcium-dependent manner to cause rapid depolarization and ion leakage, leading to bacterial cell death without requiring entry into the cytoplasm [Heidary et al., 2022]. Because this structure is fundamental to bacterial viability and differs significantly in lipid composition from eukaryotic membranes, it remains a key target for treating multi-drug resistant infections such as methicillin-resistant Staphylococcus aureus (MRSA) [StatPearls, 2023]. However, therapeutic use of membrane-targeting drugs requires monitoring for systemic toxicities, such as elevations in creatine phosphokinase indicative of muscle damage [StatPearls, 2023].

Other names

Bacterial plasma membraneBacterial inner membraneCytoplasmic membrane of Gram-positive bacteria

Drugs targeting the Gram-positive cytoplasmic membrane typically act by binding to membrane components such as phosphatidylglycerol or Lipid II, leading to membrane depolarization, pore formation, and the leakage of intracellular ions like potassium [Heidary et al., 2022]. This disruption of the membrane potential halts macromolecular synthesis and results in rapid bactericidal activity [Strahl & Hamoen, 2010].