[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Staphylococci](https://durgical.com/en/microbiology/groups/staphylococci/) › Staphylococcus epidermidis

[Microbiology](https://durgical.com/en/microbiology/) · [Staphylococci](https://durgical.com/en/microbiology/groups/staphylococci/)

# Staphylococcus epidermidis

- Bacterium
- Gram-positive
- Exam priority: medium

A normal skin bacterium that infects catheters, prostheses and artificial valves by forming a sticky biofilm.

Updated 2026-11-01

Also called: coagulase-negative staphylococcus

## Key points

- Coagulase negative, novobiocin sensitive.
- Biofilm on catheters and prostheses.
- Early prosthetic valve endocarditis.
- A single positive blood culture is usually contamination.

## At a glance

**Gram**
Gram-positive

**Shape**
Cocci in clusters

**Oxygen**
Facultative anaerobe

**Family**
Staphylococcaceae

**Stain**
Gram positive; catalase positive, coagulase negative

## Morphology

- Gram-positive cocci in clusters
- White, non-haemolytic colonies
- Novobiocin sensitive

## Transmission

- The patient's own skin flora
- Enters when catheters, prostheses or shunts are placed
- Staff hands during procedures

### Isolation precautions

What the care team adds to standard precautions.

- Standard

## Virulence factors

- Polysaccharide biofilm on plastic and metal
- The biofilm shields it from antibiotics and host defences
- Frequent methicillin resistance

## Diseases it causes

- Prosthetic valve endocarditis [Infective endocarditis →](https://durgical.com/en/conditions/infective-endocarditis/)
- Infections of venous catheters, shunts and joint prostheses

## Clinical picture

- Fever in a patient with a catheter or prosthesis
- Indolent prosthetic joint infection

## Diagnosis

- Coagulase negative, novobiocin sensitive
- Several positive blood cultures to tell infection from contamination
- A frequent contaminant of a single blood culture

## Treatment

It is often methicillin resistant, so vancomycin is common while susceptibility is pending. Removing or exchanging the infected device is often needed because the biofilm prevents cure with antibiotics alone.

Drug class only; doses and regimens are set by the clinician from the current guideline.

In Pharmacology:

- [Vancomycin](https://durgical.com/en/pharmacology/vancomycin/)

## Prevention

- Aseptic technique when inserting and handling catheters
- Removing catheters that are no longer needed
- Hand hygiene

## Memory aid

Epidermidis lives on the epidermis and sticks to plastic like a decal: where there is a line, there is suspicion.

## Test yourself

Think of the answer, then tap the question to see it.

## Which virulence factor lets S. epidermidis infect prostheses?

A polysaccharide biofilm that sticks to plastic and metal surfaces.

## Which antibiotic disc separates S. epidermidis from S. saprophyticus?

Novobiocin: S. epidermidis is sensitive and S. saprophyticus is resistant.

## How is a single positive blood culture for S. epidermidis interpreted?

Often as skin contamination; several positive cultures and clinical context are needed.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/microbiology/staphylococcus-epidermidis/)

## Related

- [Staphylococcus aureus](https://durgical.com/en/microbiology/staphylococcus-aureus/)
- [Staphylococcus saprophyticus](https://durgical.com/en/microbiology/staphylococcus-saprophyticus/)

## Related conditions

- [Infective endocarditis](https://durgical.com/en/conditions/infective-endocarditis/)

## What the colours mean

**Gram-positive**
Thick peptidoglycan wall: stains purple.

**Gram-negative**
Thin wall with an outer membrane: stains pink.

**Acid-fast**
Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain.

[← Back to the group: Staphylococci](https://durgical.com/en/microbiology/groups/staphylococci/)

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Staphylococcal Infections](https://medlineplus.gov/staphylococcalinfections.html) (MedlinePlus (NLM), 2025); [Endocarditis: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/001098.htm) (MedlinePlus (NLM), 2024).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/staphylococcus-epidermidis/