Bacterial and fungal cell envelope

The bacterial and fungal cell envelope is a complex, multi-layered structure that provides essential structural integrity and protection to microorganisms (Silhavy et al., 2010). In bacteria, the envelope typically includes a peptidoglycan cell wall and, in Gram-negative species, an additional outer membrane containing lipopolysaccharides; these structures protect the cell from osmotic lysis and environmental toxins (NIH StatPearls, 2023). Fungal cell envelopes consist of a plasma membrane containing ergosterol and a rigid cell wall composed of chitin and glucans, which are vital for maintaining cell shape and viability (Garcia-Rubio et al., 2020). Because many components of these envelopes, such as peptidoglycan and ergosterol, are absent or significantly different in human cells, they serve as primary targets for selective antimicrobial therapy (Kapoor et al., 2017). Drugs targeting the envelope work by either inhibiting the synthesis of these essential structural components or by directly disrupting the physical integrity of the membranes, leading to rapid cell death. While highly effective, targeting the cell envelope faces significant challenges, including the rise of antimicrobial resistance and potential host toxicities associated with membrane-active agents (Campoy & Adrio, 2017).

Other names

Microbial cell envelopeCell wall and membrane complexProkaryotic and fungal barrierBacterial cell wallFungal cell wall

Inhibition of peptidoglycan biosynthesis (e.g., beta-lactams inhibiting transpeptidases), binding to lipid II to prevent wall polymer cross-linking (glycopeptides), disruption of the bacterial outer membrane (polymyxins), depolarization of the cytoplasmic membrane (lipopeptides), inhibition of ergosterol biosynthesis (azoles and allylamines), pore formation in fungal membranes (polyenes), and inhibition of 1,3-beta-D-glucan synthesis (echinocandins).