STAPHYLOCOCCUS AURUS INFECTION

STAPHYLOCOCCUS AUREUS
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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 is a Gram-
positive coccal bacterium that is a member of the
Firmicutes, and is frequently found in the human
respiratory tract and on the skin. It is
positive for catalase and nitrate
reduction. Although S. aureus is not
always pathogenic, it is a common cause of skin
infections (e.g. boils), respiratory disease (e.g.
sinusitis), and food poisoning. Disease- associated
strains often promote
infections by producing potent
protein toxins, and expressing cell- surface proteins that
bind and inactivate antibodies. The emergence of
antibiotic-resistant forms of pathogenic S. aureus (e.g.
MRSA) is a worldwide problem in clinical medicine.
Staphylococcus was first identified in 1880 in Aberdeen,
United Kingdom, by the surgeon Sir Alexander Ogston in
pus from a surgical abscess in a knee joint.[1] This
name was later appended to Staphylococcus aureus by
Rosenbach who was credited by the
official system of nomenclature at
the time. It is estimated that 20% of
the human population are long-term carriers of S.
aureus[2] which can be found as part of the normal skin
flora and in anterior nares of the nasal passages.[2][3]
S. aureus is the most common species of
staphylococcus to cause Staph infections and is a
successful pathogen due to a combination of
nasal carriage and bacterial immuno-evasive strategies.
[2][3] S. aureus can cause a range of
illnesses, from minor skin infections, such as pimples,
impetigo, boils (furuncles), cellulitis folliculitis,
carbuncles, scalded skin syndrome, and abscesses, to
life-threatening diseases such as pneumonia,
meningitis, osteomyelitis, endocarditis, toxic shock
syndrome (TSS), bacteremia, and sepsis. Its incidence
ranges from skin, soft
tissue, respiratory, bone, joint,
endovascular to wound infections. It is still one of the
five most common
causes of nosocomial infections and is often the cause
of postsurgical
wound infections. Each year, some
500,000 patients in United States'
hospitals contract a staphylococcal infection.[4]
Staphylococcus aureus Classification and external
resources ICD-9 041.11 Microbiology Further
information: Coagulase- positive staphylococcal
infection Gram stain of S. Saprophyticus cells
which typically occur in clusters. The
cell wall readily absorbs the crystal violet stain. Yellow
colonies of S. aureus on a blood agar plate, note regions
of clearing around colonies caused by lysis of red cells
in the agar (beta hemolysis). S. aureus (/ˌstæfɨlɵ
ˈkɒkəs ˈɔriəs/, Greek σταφυλόκοκκος, "grape- cluster
berry", Latin aureus, "golden") is a facultative anaerobic
Gram-positive coccal bacterium also
known as "golden staph" and Oro
staphira. In medical literature the
bacteria is often referred to as S.
aureus or Staph aureus.
Staphylococcus should not be confused with the
similarly named
and medically relevant genus Streptococcus. S. aureus
appears as grape-like clusters when viewed through a
microscope, and has
large, round, golden-yellow
colonies, often with hemolysis, when grown on blood
agar plates. [5] S. aureus reproduces asexually by
binary fission. The two daughter cells do not fully
separate and
remain attached to one another. This
is why the cells are observed in clusters