Bacterium
Serratia marcescens
Red-pigmented healthcare-associated rod
seh-RAY-shuh mar-SESS-enz
High-yield clue
Red prodigiosin pigment plus DNase positivity is the classic recognition clue for this healthcare-associated rod.
Overview
A Gram-negative enteric rod famous in coursework for producing the red pigment prodigiosin at room temperature and for causing opportunistic healthcare-associated infections.
Classification
- Gram-negative
- Rod
- Enterobacterales
- Facultative anaerobe
- Motile
Lab & identification clues
- Red prodigiosin pigment vocabulary
- DNase positive concept
- Slow or late lactose fermentation
- Inducible AmpC beta-lactamase vocabulary
Associations
- Catheter and device-associated infection vocabulary
- Respiratory and urinary study association
- Multidrug-resistance framing
Commonly confused with
- Enterobacter cloacae
- Klebsiella pneumoniae
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.