PetriKey

Lab method

Acid-fast stain

Mycolic-acid wall staining concept

AS-id fast stayn

labstainacid-fastmycobacteriamycolic-acid

High-yield clue

Acid-fast positivity is the stain clue for mycolic-acid-rich organisms.

Overview

A differential staining concept used in coursework to connect mycolic-acid-rich cell walls with mycobacteria and select partially acid-fast organisms.

Classification

  • Differential stain
  • Cell-wall concept

Lab & identification clues

  • Ziehl-Neelsen vocabulary
  • Auramine-rhodamine vocabulary
  • Mycolic acid concept

Associations

  • Mycobacterium tuberculosis
  • Nocardia partial acid-fast vocabulary
  • Cryptosporidium modified acid-fast concept

Commonly confused with

  • Gram stain
  • Endospore stain

Your notes

Original concept summary for coursework. Sources checked: OpenStax Microbiology 2e and NCBI Bookshelf Medical Microbiology; reviewed 2026-06. Describes vocabulary and interpretation concepts only; not a lab protocol and not for handling specimens or identifying patient isolates.

OpenStax: Microbiology 2e staining, media, and biochemical-test foundationssourceNCBI Bookshelf: Medical Microbiology diagnostic concept foundationssource