What is the shape and stain of staphylococci?
Gram-positive cocci
What is the arrangement of staphylococci?
In Clusters
Are staphylococci motile?
No
Are staphylococci spore-forming?
No
What is the capsule of staphylococci?
- S. aureus forms microcapsule
- Other species may produce slime layer
What are staphylococci classified into?
Coagulase positive: S. aureus.
Coagulase-negative: S. epidermidis and S. saprophyticus.
What are the samples used for the diagnosis of staphylococcus aureus?
Differ according to the site of infection (swabs, pus, sputum, C.S.F, blood, …).
What are the procedures of diagnosis of Staph aureus?
1- Sample
2- Direct film
3- Culture
4- Identification of colonies
Direct film of Staph aureus
Stained with Gram stain for characteristic morphology.
Culture of staph aureus
- Facultative anaerobes, optimum temperature: 37 Β°C, normal atmospheric CO2
- Can grow on ordinary media.
- S. aureus produce golden yellow endopigments.
- S. aureus causes Ξ²-hemolysis on blood agar.
- Selective media is mannitol salt agar, where S.aureus ferments mannitol and salt inhibits other normal flora
How are colonies of staph aureus identified?
- Film stained by Gram for characteristic morphology.
- Biochemical reactions:
β All staphylococci are catalase positive.
β S. aureus is coagulase and DNAase positive and ferment mannitol.
What is catalase test used for?
.
What is the principle of catalase test?
.
What is the method of catalase test?
.
What is the interpretation of catalase test?
.
what is coagulase test used for?
.
What is the principle of coagulase test?
.
What are the types of coagulase?
.
What is DNAse agar used for?
.
What is the principle of DNAse agar?
.
What is the method of DNAse agar?
.
What is the interpretation of DNAse agar?
.
What is the significance of antimicrobial susceptibility?
.
What is the significance of phage typing?
.
