Gram-positive bacilli mnemonic

Medically important gram-positive rods

The mnemonic

ABCDL

What each word stands for

  • AActinomyces (branching, anaerobic)
  • BBacillus (aerobic spore-formers: anthrax, cereus)
  • CClostridium (anaerobic spore-formers)
  • DCorynebacterium diphtheriae
  • LListeria (tumbling motility, cold growth)

Why it matters clinically

A quick checklist when a stem gives a gram-positive rod. Then use spores, oxygen need and motility to separate them.

Where it stops being reliable

Omits Nocardia (weakly acid-fast branching rod), Mycobacterium and Propionibacterium. It lists names, not features, so you still need the features.

Teaching aid, still awaiting independent review. Confirm facts in a standard source.

More mnemonics

Common questions

What is the Gram-positive bacilli mnemonic?

ABCDL. It helps you recall: Medically important gram-positive rods.

What does "A" stand for?

Actinomyces (branching, anaerobic)

What does "B" stand for?

Bacillus (aerobic spore-formers: anthrax, cereus)

What does "C" stand for?

Clostridium (anaerobic spore-formers)

What are all the parts of the ABCDL mnemonic?

A: Actinomyces (branching, anaerobic); B: Bacillus (aerobic spore-formers: anthrax, cereus); C: Clostridium (anaerobic spore-formers); D: Corynebacterium diphtheriae; L: Listeria (tumbling motility, cold growth).

Which topic does this mnemonic belong to?

It belongs to Gram-positive bacilli in Microbiology.

Where does this mnemonic stop being reliable?

Omits Nocardia (weakly acid-fast branching rod), Mycobacterium and Propionibacterium. It lists names, not features, so you still need the features.

How is this useful clinically?

A quick checklist when a stem gives a gram-positive rod. Then use spores, oxygen need and motility to separate them.

How do I make this mnemonic stick?

Say it aloud, write it from memory tomorrow, then again in a week. Then test yourself on a Microbiology question about Gram-positive bacilli.

Is this a standard mnemonic?

It is a teaching aid written or adapted by our team. Some resemble ones students share informally. Check any fact that matters in a standard source.