Staphylococcus aureus

Staphylococci are Gram-positive bacteria, with diameters of 0.5 – 1.5 μm and characterised by individual cocci, which divide in more than one plane to form grape-like clusters. Gram staining is a staining technique used in microbiology to identify the cell wall structure of bacteria if a bacterium is gram-positive it has a cell wall higher in peptidoglycan and lower in lipid than gram-negative bacteria.

To date, there are 32 species and eight sub-species in the genus Staphylococcus, many of which preferentially colonize the human body, however Staphylococcus aureus and Staphylococcus epidermidis are the two most characterized and studied strains.

Staphylococcus aureus is found in the environment and is also found in normal human flora, located on the skin and mucous membranes (most often the nasal area) of most healthy individuals. Staphylococcus aureus is a major pathogen of increasing importance due to the rise in antibiotic resistance.

Staphylococcus aureus may colonize the human body as a part of the normal flora. Approximately 30 % of healthy people are inhabited by Staphylococcus aureus, mostly in the anterior nares. Staphylococcus aureus is also a leading cause of hospital-associated (HA) and community-associated (CA) bacterial infections in humans, associating with numerous mild skin and soft tissue infections, as well as life-threatening pneumonia, bacteraemia, osteomyelitis, endocarditis, sepsis and toxic shock syndrome.

The first-line of natural defense against Staphylococcus aureus is the native immune system and the next line of defense against Staphylococcus aureus infection is the use of antibiotics, but as with all antibiotics misuse or overuse of these agents has in part lead to resistant strains of Staphylococcus aureus.
Staphylococcus aureus