What are the components of Aerobic Gram Positive cocci?
- Staphylococci (clusters)
- Streptococci and Enterococci (chains)
What is the result of coagulase test in differentiating Staphlococci?
Coagulase-positive=Staphylococcus aureus which can be either MRSAor MSSA.
Descibe the characteristics of Staphylococcus aureus?
- Commensal organism carried in nose, axilla, perineum.
- Wide range of disease from boils/abscesses and soa issue infections to septecaemia and osteomyelits.
- Commonly penicillin resistant due to production of penicillinase.
What are the coagulase-negative staphylococci?
- Many different species e.g. S. epidemidis
- Mainly skin commensals.
- Form biofilms and may be significant pathogens in the presence of foreign bodies/prostheses e.g. prosthe@c heart
What are the properties of Streptococci?
• α- haemolytic (partial haemolysis)
-> turn blood agar green
• β-haemolytic (complete haemolysis)
-> turn blood agar clear
• Non haemolytic
Give an example of α-haemolytic streptococci?
-> pneumonia, meningitis, septecaemia
What are the feutures of β-haemolytic streptococci?
- Further identified by carbohydrate surface antigens.
- further identified by Groups A-G.
• A, B, F and D clinically most important.
What are the constituents of Gram positive bacilli?
- Anaerobic:Clostridium tetani,Clostridium perfringens and Clostridium difficile.
What are the feutures of Clostridium difficile?
- “Difficult” to culture.
- Asymptomaticc gut carriage in healthy people
. • Important cause of diarrhoea, associated with toxin production and potentially fatal
What are the feutures of Clostridium perfringens?
- Found in soil and normal commensal in human and animal gut/faeces.
- Can contaminate food
What are the feutures of Clostridium tetani?
- Toxin production by C. tetani cause tetanus.
• Uncontrolled muscle spasm due to loss of inhibition at neuromuscular junction.
Gram negative flow chart
Gram postive flow chart