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Bacterium

Shigella species

Nonmotile non-lactose fermenting rod

shih-GEL-uh

Gram negativebacteriagram-negativerodnonmotileenterictoxin

High-yield clue

Nonmotile non-lactose fermenter is the classic Salmonella contrast.

Overview

Enteric Gram-negative rods used in coursework to contrast nonmotility, non-lactose fermentation, and toxin-mediated vocabulary with Salmonella and E. coli.

Classification

  • Gram-negative
  • Rod
  • Enterobacterales

Lab & identification clues

  • Non-lactose fermenter
  • Nonmotile teaching clue
  • Shiga toxin vocabulary (classically S. dysenteriae type 1)

Associations

  • Dysentery vocabulary
  • Low infectious-dose concept
  • Food/water public-health framing

Commonly confused with

  • Salmonella enterica
  • E. coli pathotypes
  • Campylobacter jejuni

Frequently asked questions

What is Shigella species?

Enteric Gram-negative rods used in coursework to contrast nonmotility, non-lactose fermentation, and toxin-mediated vocabulary with Salmonella and E. coli.

What is the Gram stain of Shigella species?

Shigella species is Gram negative.

What are the lab clues for Shigella species?

Lab clues for Shigella species include Non-lactose fermenter, Nonmotile teaching clue, and Shiga toxin vocabulary (classically S. dysenteriae type 1).

What is Shigella species commonly confused with?

Shigella species is commonly confused with Salmonella enterica, E. coli pathotypes, and Campylobacter jejuni.

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