epidermidis

Staphylococcus epidermidis is a Gram-positive, non-motile coccus that commonly occurs in grape-like clusters. It is facultatively anaerobic and coagulase-negative. S. epidermidis is a natural inhabitant of human skin and mucous membranes, particularly on the anterior nares, scalp, and upper body, where it forms part of the normal microbiota.

Although it generally has low virulence, S. epidermidis is an important opportunistic pathogen in healthcare settings. Its ability to adhere to abiotic surfaces and produce robust biofilms enables persistence on indwelling medical devices such as catheters, prosthetic joints, and prosthetic heart valves. Biofilms protect the bacteria from antibiotics and immune defenses, contributing to persistent or recurrent infections.

Clinically significant infections include bloodstream infections, catheter-related infections, prosthetic joint infections, prosthetic valve endocarditis, and shunt infections. Risk factors include recent surgery, implanted devices, immunosuppression, and prolonged hospitalization. Outbreaks can occur in hospitals due to contaminated equipment or solutions.

Laboratory identification typically shows Gram-positive cocci in clusters that are catalase-positive and coagulase-negative. S. epidermidis is commonly reported as novobiocin sensitive. Methicillin resistance is increasingly encountered, complicating treatment. Management often requires removal of the infected device when feasible, combined with targeted antibiotic therapy guided by susceptibility testing. Therapeutic options may include vancomycin, linezolid, or daptomycin, among others.

As part of normal skin flora, S. epidermidis is usually harmless in healthy individuals. Prevention of device-associated infections relies on strict aseptic technique, proper device care, and minimizing unnecessary indwelling devices.