Overview
Staphylococci are a genus of Gram-positive, facultatively anaerobic cocci that can be found naturally on the skin and mucous membranes but may cause invasive disease. They are often found singly, in pairs, or in clusters.
Staphylococcus aureus
Staphylococcus aureus is a potentially pathogenic bacterium found on the skin, the nasal membranes, and hair follicles. It is coagulase-positive and can cause:
- Skin infections – cellulitis, impetigo, folliculitis, mastitis, and necrotising fasciitis
- Bone and joint infections – septic arthritis, osteomyelitis, and discitis
- Toxic syndromes – staphylococcal scalded skin syndrome, toxic shock syndrome
Methicillin-Resistant Staphylococcus aureus
Methicillin-Resistant Staphylococcus aureus (MRSA) is a strain of Staphylococcus aureus that is resistant to methicillin, a beta-lactam antibiotic. MRSA is resistant to all beta-lactams due to alterations in the penicillin-binding proteins in its cell wall.
Staphylococcus epidermidis
Staphylococcus epidermidis is a coagulase-negative species of the Staphylococcus genus that is mainly found in the skin and mucous membranes. It is implicated in the infections of medical lines and devices such as central lines, prosthetic valve infective endocarditis, peritoneal dialysis-associated peritonitis etc.
