Staphylococcus aureus

Staphylococcus aureus

Scanning electron micrograph of S. aureus; false color added
Scientific classification
Domain:	Bacteria
Kingdom:	Eubacteria
Phylum:	Firmicutes
Class:	Bacilli
Order:	Bacillales
Family:	Staphylococcaceae
Genus:	Staphylococcus
Species:	S. aureus
Binomial name
*Staphylococcus aureus* Rosenbach 1884

Staphylococcus aureus
Classification and external resources
Specialty	Infectious disease
ICD-9-CM	041.11
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Staphylococcus aureus is a gram-positive coccal bacterium that is a member of the Firmicutes, and is frequently found in the nose, respiratory tract, and on the skin. It is often positive for catalase and nitrate reduction and is a facultative aerobe that can grow without the need for oxygen. Although S. aureus is not always pathogenic, it is a common cause of skin infections such as abscesses, respiratory infections such as sinusitis, and food poisoning. Pathogenic strains often promote infections by producing potent protein toxins, and expressing cell-surface proteins that bind and inactivate antibodies. The emergence of antibiotic-resistant strains of S. aureus such as methicillin-resistant S. aureus (MRSA) is a worldwide problem in clinical medicine.

Staphylococcus was first identified in 1880 in Aberdeen, Scotland, by the surgeon Sir Alexander Ogston in pus from a surgical abscess in a knee joint. This name was later amended to Staphylococcus aureus by Friedrich Julius Rosenbach, who was credited by the official system of nomenclature at the time. An estimated 20% of the human population are long-term carriers of S. aureus which can be found as part of the normal skin flora and in the nostrils.S. aureus is a normal inhabitant of the healthy lower reproductive tract of women.S. aureus can cause a range of illnesses, from minor skin infections, such as pimples,impetigo, boils, cellulitis, folliculitis, carbuncles, scalded skin syndrome, and abscesses, to life-threatening diseases such as pneumonia, meningitis, osteomyelitis, endocarditis, toxic shock syndrome, bacteremia, and sepsis. It is still one of the five most common causes of hospital-acquired infections and is often the cause of postsurgical wound infections. Each year, around 500,000 patients in hospitals of the United States contract a staphylococcal infection, chiefly by S. aureus.