FAMILY –  Staphylococcaceae.  (consist of gram-positive cocci, arranged in tetrads, and clusters)
GENUS –Staphylococcus derived from Greek ( staphylo = bunch of grapes
coccus = berry )

History Staphylococus ​

• Staphylococci were first observed in human pyogenic lesions  by von Recklinghausen ( 1871 ) in a pus specimen.

• Pasteur (1880)obtained liquid culture of the cocci from pus and produced abscesses by inoculating them into rabbits.

• Staphylococcus ( Staphyle in geek, meaning “a bunch of grapes.)

• It was Sir Alexander Ogston,a Scottish surgeon, who established conclusively the causative role of the coccus in abscesses and suppurative lesion (1880). He was the one who named the bacteria as “Staphylococcus “

• Rosenbach (1884) named them staph. Aureus and Staph. Albus and s.citrus

Classification

Based on pigment production

• S . Aureus: golden yellow pigment colonies
• S . albus : white colonies
• S . citrus: lemon yellow colonies

Based on pathogenicity

• Pathogenic: S. Aureus
• Non pathogenic : S.albus , S.citus

Based on coagulase production

• Coagulase positive : S.aureus
• Coagulase negative : S.albus, s.citus

Morphology

They are spherical cocci,
Diameter -1 um approx.
Grapes like cluster arrangement ( Cluster formation is due to cell division occurring in three planes, the daughter cells tending to remain in close proximity)
Nonmotile and nonsporing
Found singly, in pair and in short chains of three or four cells, especially when examined from liquid culture.

Culture

Temperature range: 10-42 degrees Celsius
PH: 7.4 – 7.6
On nutrient agar
— Golden yellow and opaque colonies with a smooth glistening surface, 1-2 mm in diameter are present

On blood agar
— golden yellow colonies surrounded by clear zone of hemolysis. When incubated in sheep or rabbit blood agar in the atmosphere of 20% CO2

On Mac Conkey agar
—smaller colonies than those on NA ( 0.1-0.5 mm ) are pinked colored due to lactose fermentation.

Biochemical properties

Indole test = negative ,
MR test = positive ,
VP test = positive ,
Urease test = positive ,
Hydrolyse = gelatin,
Reduces = nitrate to nitrite,
Phosphatase= positive,
DNA – ase test = positive ,
Coagulase test = positive.

Staphylococcal diseases

1. SKIN AND SOFT TISSUE: folliculitis,  furuncle,  abscess, wound infection, carbuncle, impetigo, paronychia.
2. MUSCULOSKELETAL: osteomyelitis, arthritis,
   Bursitis, pyomyositis
3. RESPIRATORY: Tonsillitis, pharyngitis, sinusitis, otitis, bronchopneumonia.
4. CENTRAL NERVOUS SYSTEM: meningitis, abscess
5. ENDVASCULAR : bacteremia , pyemia , endocaritis
6. URINARY: urinary tract infection

Measure taken to control infection 

• Isolation of patient
• Detection of the staphylococcal lesion
• Using strict aseptic techniques in theatres
• Hand washing { mostly neglected by staff}

Treatment

1. Oral antibiotics ( taken by mouth )
2. Tropical antibiotics ( applied on the skin )
3. IV antibiotics ( intravenous )