Basic Knowledge of Lipopolysaccharide (LPS)

(4) Gram-negative Bacteria and LPS

LPS is a bacterial component, but it is not associated with bacterial pathogenicity.

All bacteria are classified into two types: gram-negative and gram-positive. The types are distinguished by whether or not they are stained by the staining method developed by Danish scholar Dr. Hans Gram. Whether it is stained or not with Gram stain depends on the structure of the cell wall, and the difference in structure of the cell wall shows the difference of phylogeny of two types of bacteria..

LPS is present only in gram-negative bacteria, which include both useful and pathogenic bacteria. Useful gram-negative bacteria include acetic acid bacteria that are used in acetic acid fermentation; Zymomonas mobilis that is used in tequila fermentation; Xanthomonas bacteria that produce xanthan gum, which is used as a polysaccharide thickener for food; and Pantoea agglomerans that coexists on edible plants and suppresses fungi growth. On the other hand, pathogenic gram-negative bacteria include Vibrio cholerae and Salmonella species. As mentioned above, the presence or absence of pathogenicity is unrelated to LPS. For example, eating only Salmonella-derived LPS will not cause food poisoning.

In addition, gram-positive bacteria also have useful bacteria and pathogenic bacteria. Representative strains of useful bacteria are lactic acid bacteria. Staphylococcus aureus, Mycobacterium tuberculosis, etc. are the pathogenic bacteria.