Staphylococcus aureus

Staphylococcus aureus is a pathogenic bacterium in human beings.

Features of Staphylococcus aureus

Staphylococcus aureus belongs to the Staphylococcus genus and is a Gram positive bacterium which is a coccus, and forms clusters (raisin bunches) or chains. The bacterial cell is approximately 1 micrometre in diameter and is immobile.

The genome is contained on a chromosome of approximately 2.8 million base pairs which code 2,700 proteins.

Staphylococcus aureus and infections

Although it is often found in human beings, it does not always cause infection. It can cause skin infections (boils, folliculitis, whitlow, impetigo etc) or mucosal infections (otitis, conjunctivitis, etc.) which may result in septicaemia. It also causes nosocomial infections, food poisoning and its antibiotic resistance is occasionally a major problem in treating patients.

Staphylococcus aureus produces various toxins: haemolysins, leukocidin, enterotoxins, Staphylococcal toxic shock toxin or TSST-1 (temperature over 39°C, hypotension, erythroderma, which is fatal in 10% of patients), and exfoliatins.