What is Staphylococcous ?
A gram positive cocci and that is arranged in grape like clusters. They mainly cause suppuration
The important species of Staphylococcus are –
- Staph.aureus
- Staph.epidermidis
- Staph.saprophyticus
Staphylococcus aureus
- They are gram positive cocci
- Arranged in grape like clusters
- They are non motile,non sporing
- Diameter – 1 micrometer approx.
- Grow in culture medium between 10-42 degree celcius but approximately at 37 degrees celcius
- Grow at a pH of 7.4-7.6
- They are aerobes and facultative anaerobes (which can also grow without oxygen)
Pathogenesis
- It is a very important pyogenic organism and lesions are localized in nature.
- They produce thick cream colored colonies
They are classified as –
- cutaneous and deep infections
- nosocomial infections
- food poisoning
- skin exfoliative diseases
- toxic shock syndrome
1.Cutaneous infecctions – superficial infecctions
- pustules
- boils
- carbuncles
- impetigo
- pemphigus neonatrum
- styes
- abscesses
- wound and burn infections
2. Deep infections
- osteomyelitis
- tonsillitis
- pharyngitis
- pneumonitis
- endocarditis
- empyema
- bacteremia
- septicemia
- meningitis
- sinusitis
3. Food poisoning –
Staphylococcal food poisoning may follow 2-6 hrs after injestion of contaminated food that has preformed entertoxin.
4.Nosocomial infections –
They are important cause of hospital acquired infections
5.Skin exfoliative Diseases
- These are produced by strains of Staph.aureus .
- There is stripping of the superficial layers of skin from the underlying tissue .
- They are Ritters disease ,pemphigous neonatrum,bullous impetigo.
- Staphylococcocal scaled skin syndrome (SSSS) is the example. In this the toxin is spread systemically.
6. Toxic shock syndrome –
- It is caused by TSST-1 ( toxic shock syndrome toxin ). This is characterised by high fever,hypotension, diarrhoea, scarletiniform rash,vomiting.
- It is also associated with use of tampons by mentruating women which is rare.
source – C P Baveja textbook of microbiology for dental students and google images
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