Laboratory Diagnosis of Staphylococci Infection
Aureus should be grown under aerobic conditions. On blood agar, S. aureus colonies are typically golden-yellow in colour, and a zone of B-haemolysis may be present. Fermentation of mannitol and growth in high salt concentration provide further suggestive evidence. S. Aureus can only be definitively identified by the presence of coagulase.
Minor lesions do not generally require anti-microbial treatment. Localized abscesses should be drained. Antibiotics can be used to inhibit dissemination. Systemic disease must be treated vigorously with an appropriate antibiotic. Penicillin is the drug of choice should the strain responsible be sensitive to it. Otherwise, in the absence of sensitivity data, empirical treatment may be started with a penicilinase-resistant agent such as ampicillin. In certain hospital settings throughout the world, serious nosocomial epidemics are cause by S. aureus strains resistant to all antibiotics except vancomycin.