Pathogen cell membranes and cell walls

Pathogen cell membranes and cell walls represent the primary structural defenses of bacteria, fungi, and certain parasites, serving as essential barriers against osmotic stress and host immune factors. In bacteria, the cell wall is primarily composed of peptidoglycan, a complex polymer whose synthesis is targeted by major antibiotic classes like beta-lactams and glycopeptides (StatPearls, 2023). Fungal cell walls contain unique polysaccharides such as chitin and beta-glucans, while their membranes utilize ergosterol instead of cholesterol, providing specific targets for echinocandins and polyenes, respectively (Nature Reviews Microbiology, 2017). Because these structures are often unique to microbes, they offer a high degree of selective toxicity, making them some of the most successful targets in clinical medicine. However, direct membrane-disrupting agents, such as polymyxins, can sometimes exhibit toxicity in humans due to similarities between pathogen and host lipid bilayers (PubMed, 2021). The clinical utility of targeting these structures is increasingly threatened by the evolution of resistance mechanisms, including the modification of target sites, cell wall thickening, and the upregulation of efflux pumps.

Other names

Microbial cell envelopeBacterial cell wallFungal cell wallPathogen plasma membraneBacterial envelopeFungal envelope

Drugs targeting these structures work by either inhibiting the biosynthesis of essential structural components, such as peptidoglycan cross-linking (beta-lactams) or beta-glucan synthesis (echinocandins), or by directly disrupting the physical integrity of the lipid membrane through pore formation or detergent-like action (polymyxins, polyenes), leading to cytoplasmic leakage and cell death.