Micrococcus luteus

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Micrococcus Luteus
Scientific classification
Kingdom: eubacteria Phylum: Actinobacteria Order: Actinomycetales Family: Micrococcaceae Genus: Micrococcus Species: M. luteus
Binomial name
Micrococcus Luteus

Description and significance

Micrococcus Luteus most commonly known as M.Luteus is a non-pathogenic, gram-positive bacteria that is most commonly found in mucous membranes, dust, soil the air that we breathe and human skin. The bacteria is an obligate aerobe which can also live in very low concentrations of carbon. Although believed to be harmless,it is often found to be involved in infections resulting from a patient staying at a hospital for instance. It is often hard to consider M.Luteus as the cause of the diseases resulting from it since the bacteria is constantly and mostly found on human skin and in nasal cavities.

Cell structure and metabolism

Micrococcus luteus grows yellow round-shaped colonies. Its cell wall is made of peptidoglycans linked together by amino-acids which would explain its ability to absorb the dark-blue or violet stains. It is known to cause odors in humans because of its ability to break down sweat components.

Ecology

M.luteus can be found mostly in environments where the temperature is around 37oC since this is the temperature at which its usual milieu is known to be (skin/nasal cavity). The bacteria grows also in beer and its lifetime is limited in soil. M.luteus is specially known for its growth in dairy products which facilitates its transmission to its host after consumption milk for instance. This organism is able to grow on inorganic nitrogen and cannot synthesize acid from glucose in the presence of oxygen.

Pathology

As stated before, Micrococcus is not considered as a pathogen but rather as a bacteria that jumps on the first opportunity to enhance some infections in its host. When an individual is affected by its lack of immunity, M.luteus tends to improve (boost)certain diseases like : meningitis, pneumonia, urinary tract infections. That's why hospitalized patients are mostly succeptible to be victims of M.luteus' opportunistic's side of its pathology.

Application to Biotechnology

M. Luteus has been used to make some studies on microbes’ susceptibility to [lactoferrin] (Lf), a glycoprotein. Lactoferrin is known to exert antibacterial activities by binding to the [lipomannan] of the cell wall of the microbe. The protein (mostly found in mammalian [exocrine] secretion) leads to the destruction of its host in certain species. For instance, in the Micrococcus genus, the glycoprotein is only effective in the M. luteus species but not for [M. radiophilus], [M.roseus] or [M.varians]. However, lactoferrin is known for its iron-binding capacities. Since iron is one of the factors promoting microbial viability and growth, its binding to Lf stops the bactericidal effect. The studies show that the amount of iron present for the lactoferrin to bind, plays an important role in such activity. It is showed that the ferric salts were able to stop the antibacterial effect more than the ferrous salts could.