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PetriKey

Bacterium

Staphylococcus aureus

Gram-positive cocci in clusters

STAFF-ih-lo-KOK-us AW-ree-us

Gram positivegram-positivecoccicatalasecoagulaseskintoxin

High-yield clue

Clusters + catalase positive + coagulase positive is the classic study clue.

Overview

A high-yield Gram-positive coccus commonly used to connect catalase, coagulase, toxin concepts, abscess patterns, and antimicrobial resistance vocabulary.

Classification

  • Gram-positive
  • Cocci
  • Clusters
  • Facultative anaerobe

Lab & identification clues

  • Catalase positive
  • Coagulase positive
  • Golden colonies in many teaching examples
  • Beta-hemolysis is often emphasized in class

Associations

  • Skin and soft-tissue infection concepts
  • Food poisoning toxin concept
  • Toxic shock toxin concept
  • MRSA as resistance vocabulary

Commonly confused with

  • Staphylococcus epidermidis
  • Streptococcus pyogenes

Frequently asked questions

What is Staphylococcus aureus?

A high-yield Gram-positive coccus commonly used to connect catalase, coagulase, toxin concepts, abscess patterns, and antimicrobial resistance vocabulary.

What is the Gram stain of Staphylococcus aureus?

Staphylococcus aureus is Gram positive.

What are the lab clues for Staphylococcus aureus?

Lab clues for Staphylococcus aureus include Catalase positive, Coagulase positive, Golden colonies in many teaching examples, and Beta-hemolysis is often emphasized in class.

What is Staphylococcus aureus commonly confused with?

Staphylococcus aureus is commonly confused with Staphylococcus epidermidis and Streptococcus pyogenes.

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