PetriKey

Lab method

MacConkey agar concept

Lactose-fermentation sorting vocabulary

muh-KON-key

Gram negativelabagarlactosegram-negativeenteric

High-yield clue

Lactose fermenter versus nonfermenter is the study branch, not a standalone ID.

Overview

A selective/differential media concept used in coursework to contrast lactose-fermenting and non-lactose-fermenting Gram-negative rods.

Classification

  • Selective/differential media concept
  • Enteric sorting vocabulary

Lab & identification clues

  • Lactose fermentation vocabulary
  • Gram-negative selection concept
  • Colony-color concept without protocol details

Associations

  • E. coli
  • Klebsiella pneumoniae
  • Salmonella/Shigella contrast

Commonly confused with

  • Blood agar
  • Chocolate agar

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