belongs to the family Staphylococcaceae.
It affects all known mammalian species, including humans. Further due to its ability to affect a wide range of species, S. aureus
can be readily transmitted from one species to another. This includes transmission between humans and animals.
Transmission of Staphylococcus aureus
may occur commonly in the environment. S. aureus
is transmitted through air droplets or aerosol. When an infected person coughs or sneezes, he or she releases numerous small droplets of saliva that remain suspended in air. These contain the bacteria and can infect others.
Another common method of transmission is through direct contact with objects that are contaminated by the bacteria or by bites from infected persons or animals. Approximately 30% of healthy humans carry S. aureus in their nose, back of the throat and on their skin.
Clinical manifestation of infection
Around one third of healthy individuals carry this bacteria in their noses, pharynx and on their skin. In normal healthy and immunocompentent person, S. aureus colonization of the skin, intestinal tract, or nasopharynx does not lead to any symptoms or disease.
When S. aureus
is isolated from an abscess or boil or other skin lesion, it is usually due to its secondary invasion of a wound rather than the primary cause of disease. S. aureus
may similarly be isolated from abscesses, breast absecesses or mastitis, dermatitis
or skin infections and genital tract infections.
is considered the classic opportunist in this way since it takes advantage of broken skin or other entry sites to cause an infection.
In animals and humans that are immunocompromised or immunodeficient, this bacteria may be life threatening. It may lead to pyogenic (abscessing) infections of the skin, eyes and genital tract.
What does S. aureus cause?
Of the variety of manifestations S. aureus
Presence of S. aureus in culture is normally insignificant since this bacteria is normally present on the skin, nose and pharynx of many humans and animals.
The organism is readily cultured from nasopharynx or skin, or by culture of suspicious lesions.
On culture the bacterial colonies a characteristic glistening, opaque, yellow to white appearance on blood agar.