Bacterial capsules: Occurrence, mechanism, and function

Abstract

In environments characterized by extended multi-stress conditions, pathogens develop a variety of immune escape mechanisms to enhance their ability to infect the host. The capsules, polymers that bacteria secrete near their cell wall, participates in numerous bacterial life processes and plays a crucial role in resisting host immune attacks and adapting to their niche. Here, we discuss the relationship between capsules and bacterial virulence, summarizing the molecular mechanisms of capsular regulation and pathogenesis to provide new insights into the research on the pathogenesis of pathogenic bacteria.

Molecular Mechanisms of Bacterial Resistance to Antimicrobial Peptides in the Modern Era: An Updated Review

“…The production of capsule polysaccharides (CPSs) is involved in adjusting biofilm formation to cause persistent infections in the blood, respiratory tract, and gastrointestinal mucosa of mammals [399,400]. Additionally, it can either confer resistance or reduce susceptibility to several AMPs and evade phagocytosis [401]. While the chemical composition of CPSs varies widely among bacterial species, the majority of them are anionic.…”

AI-2 quorum sensing-induced galactose metabolism activation in Streptococcus suis enhances capsular polysaccharide-associated virulence

“…The survival of S. suis in the respiratory tract, a key factor in its transmission and infection, is primarily associated with its virulence factor, capsular polysaccharide (CPS) [ 3 ]. CPS plays a role in adhesion and is a crucial virulence factor facilitating bacterial invasion of host cells [ 4 , 5 ]. In 2001, Magee and Yother highlighted the role of CPS in Streptococcus pneumoniae ( S. pneumoniae ) colonization, noting that mutants producing only 20% CPS exhibited reduced invasive and lethal capabilities [ 6 ].…”

Editorial: Bacterial surface polymers

“…The bacterial surface is an essential structure that mediates all interactions between a bacterial cell and its immediate extracellular environment. Bacterial polymers are integral components of this surface architecture, which function in a multitude of cellular processes including cell division and spatial organization, molecular trafficking, protection from antimicrobial agents, and interaction with and evasion of the host ( Gao et al., 2024 ; Brown et al., 2013 ; Sabnis et al., 2018 ; Brignoli et al., 2022 ). Their importance is highlighted by the stringent regulation of their synthesis, complex molecular machinery driving their biosynthesis, and the metabolic costs invested in their production ( Whitfield et al., 2020 ; Galinier et al., 2023 ).…”