Teichoic acids were discovered in 1958 by Armstrong and co-authors.
The term teichoic acid encompasses a diverse family of cell surface glycopolymers containing phosphodiester- linked polyol repeat units. Teichoic acids are fibres of glycerol phosphate (glycerol teichoic acid) or ribitol phosphate (ribitol teichoic acid).
Substituent group on the polyol chains can include D-alanine (ester linked), N-acetylglucosamine, N-acetylgalactosamine, and glucose; the substituent is characteristic for the teichoic acid from a particular bacterial species and can act as a specific antigenic determinanat.
Teichoic acids are located in the outer layer of certain gram positve bacteria (such as Staphylococci, Streptococci, Lactobacilli and Bacillus spp). So far teichoic acids have not been found in Gram Negative Bacteria.
Wall teichoic acids are intimately involved in many aspects of cell division and are essential for maintaining cell shape in rod-shaped organisms. WTAs are required for ß-lactam resistance in methicillin-resistant S. aureus (MRSA), and they modulate susceptibility to cationic antibiotics in several organisms.
Lipoteichoic acid: Teichoic acid that covalently linked to the lipid in the cytoplasmic membrane. Some techoic acids anchor to the muramic acid in the peptidoglycan.
Medical Importance of Teichoic Acid:
- Teichoic acids play a role in pathogenesis by promoting adherence to host tissues. e.g. They mediate the attachment of staphylococci to mucosal cells.
- They induce septic shock through the same pathways as does endotoxin (Lipopolysaccharide ) in gram negative bacteria.
- Teichoic acids are highly negative charged polymers so they can serve as a cation-sequestering mechanism.