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PetriKey

Bacterium

Staphylococcus epidermidis

Coagulase-negative skin flora clue

STAFF-ih-lo-KOK-us EP-ih-der-MID-is

Gram positivegram-positivecoccicatalasecoagulase-negativebiofilm

High-yield clue

Clusters + catalase positive + coagulase negative points away from S. aureus.

Overview

A coagulase-negative staphylococcus frequently used in study questions about normal skin flora and device-associated biofilm concepts.

Classification

  • Gram-positive
  • Cocci
  • Clusters
  • Coagulase-negative staphylococcus

Lab & identification clues

  • Catalase positive
  • Coagulase negative
  • Novobiocin-sensitive distinction is commonly taught

Associations

  • Skin flora
  • Biofilm vocabulary
  • Device-associated infection concepts in educational cases

Commonly confused with

  • Staphylococcus aureus
  • Staphylococcus saprophyticus

Frequently asked questions

What is Staphylococcus epidermidis?

A coagulase-negative staphylococcus frequently used in study questions about normal skin flora and device-associated biofilm concepts.

What is the Gram stain of Staphylococcus epidermidis?

Staphylococcus epidermidis is Gram positive.

What are the lab clues for Staphylococcus epidermidis?

Lab clues for Staphylococcus epidermidis include Catalase positive, Coagulase negative, and Novobiocin-sensitive distinction is commonly taught.

What is Staphylococcus epidermidis commonly confused with?

Staphylococcus epidermidis is commonly confused with Staphylococcus aureus and Staphylococcus saprophyticus.

Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.

OpenStax: Microbiology 2e organism classification foundations - sourceNCBI Bookshelf: Medical Microbiology organism chapters - sourceCDC: CDC disease and public-health topic pages - source