Staphyloxanthin is a

carotenoid Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic compound, organic pigments that are produced by plants and algae, as well as several bacteria, and Fungus, fungi. Carotenoids give the characteristic color to pumpki ...

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

that is produced by some strains of ''

Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive ...

'', and is responsible for the characteristic golden color that gives ''S. aureus'' its species name. Staphyloxanthin also acts as a virulence factor. It has an

antioxidant Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubricant ...

action that helps the microbe evade death by

reactive oxygen species In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen. The reduction of molecular oxygen () p ...

produced by the host immune system. Staphylococcus aureus on TSA

When comparing a normal strain of ''S. aureus'' with a strain modified to lack staphyloxanthin, the wildtype pigmented strain was more likely to survive incubation with an oxidizing chemical such as

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%� ...

than the mutant strain was. Colonies of the two strains were also exposed to human

neutrophils Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying in ...

. The mutant colonies quickly succumbed while many of the pigmented colonies survived. Wounds on mice were inoculated with the two strains. The pigmented strains created lingering

abscess An abscess is a collection of pus that has built up within the tissue of the body. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pressed. The area of redness often extends b ...

es. Wounds with the unpigmented strains healed quickly. These tests suggest that the staphyloxanthin may be key to the ability of ''S. aureus'' to survive immune system attacks. Drugs designed to inhibit the bacterium's production of the staphyloxanthin may weaken it and renew its susceptibility to antibiotics. In fact, because of similarities in the pathways for biosynthesis of staphyloxanthin and human

cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...

, a drug developed in the context of cholesterol-lowering therapy was shown to block ''S. aureus'' pigmentation and disease progression in a mouse infection model.

References

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External links

Staphyloxanthin on www.genome.jp
Carotenoids Glucosides Staphylococcus