Staphylococcus epidermidis colonies on tryptic soy agar plate
Staphylococcus epidermidis on Tryptic Soy Agar, cultivation 24 hours, 37°C
Staphylococcus epidermidis is part of the normal human flora, typically the skin flora, and less commonly the mucosal flora. Although S. epidermidis is not usually pathogenic, patients with compromised immune systems are at risk of developing infection. These infections are generally hospital-acquired. S. epidermidis is a particular concern for people with catheters or other surgical implants because it is known to form biofilms that grow on these devices.
The normal practice of detecting S. epidermidis is by using the Baird-Parker agar with egg yolk supplement. Colonies appear small and black. They can be confirmed using the coagulase test (negative).