Staphylococcus aureus

Staphylococcus aureus is a Gram positive coccus when viewed microscopically after Gram’s stain. This bacteria is coagulase positive. It is a common cause of skin and soft tissue infections such as wound infections after surgery, pustules and cellulitis (infection of the skin and subcutaneous tissues). Staphylococcus aureus colonizes skin of at least 25% of people. The highest concentration of the bacteria within these people is within the nostrils. There are two major antibiotic resistance profiles: (1) methicillin susceptible Staphylococcus aureus which can be treated with most beta-lactam antibiotics such as nafcillin, oxacillin and cephalosporins, (2) methicillin resistant Staphylococcus aureus (MRSA) which is resistant to the beta-lactam antibiotics mentioned above, but is typically susceptible to vancomycin, linezolid, daptomycin and tigecycline.