Bacterium
Nocardia species
Branching weakly acid-fast aerobic rods
noh-KAR-dee-uh
High-yield clue
Branching filamentous rods + weak acid-fast vocabulary + aerobic contrast.
Overview
Branching aerobic bacteria used to contrast weak acid-fast staining with Actinomyces and Mycobacterium in morphology drills.
Classification
- Gram-positive branching rod
- Weakly acid-fast
- Aerobe
Lab & identification clues
- Modified acid-fast vocabulary
- Branching filamentous morphology
- Soil/environmental association
Associations
- Pulmonary opportunistic infection vocabulary
- Brain abscess association in coursework
- Cell-mediated immunity concept
Commonly confused with
- Actinomyces species
- Mycobacterium tuberculosis
- Aspergillus fumigatus
Your notes
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.