Microbial cell membrane and lipid

Microbial cell membranes and lipids are essential components that provide structural integrity, regulate nutrient transport, and facilitate energy transduction in bacteria and fungi. These membranes are characterized by unique lipid compositions, such as the presence of ergosterol in fungi and high concentrations of anionic phospholipids like phosphatidylglycerol in bacteria, which distinguish them from cholesterol-rich mammalian membranes (Source: Nature Reviews Microbiology, 2017). These differences are exploited by several classes of antibiotics and antifungals to achieve selective toxicity. For instance, daptomycin and polymyxins target bacterial membranes to induce cell death through depolarization or physical disruption, while polyenes target fungal ergosterol. Despite their efficacy, drugs targeting these structures often face challenges related to host toxicity, particularly nephrotoxicity and neurotoxicity, due to partial cross-reactivity with human cell membranes or mitochondrial lipids (Source: StatPearls, Polymyxin B). Nevertheless, the cell membrane remains a critical target for treating multi-drug resistant (MDR) pathogens because its fundamental structural nature makes the development of high-level resistance more complex than for single-protein targets.

Other names

Bacterial cell membraneFungal cell membraneMicrobial lipid bilayerCytoplasmic membraneBacterial cytoplasmic membrane

Drugs targeting microbial membranes function through several distinct mechanisms. Lipopeptides like daptomycin bind to the cytoplasmic membrane of Gram-positive bacteria in a calcium-dependent manner, causing rapid depolarization and potassium efflux (Source: StatPearls, Daptomycin). Polyene antifungals, such as amphotericin B, bind to ergosterol in fungal cell membranes, leading to the formation of aqueous pores that cause leakage of intracellular contents (Source: PubMed, PMID: 24161596). Polymyxins, including colistin, act as cationic detergents that bind to the lipid A portion of lipopolysaccharides (LPS) in Gram-negative bacteria, disrupting both the outer and inner membranes (Source: PubMed, PMID: 25130030). Lipoglycopeptides like oritavancin also exhibit membrane-disrupting activities in addition to inhibiting cell wall synthesis.