Tour of Microbes   Tour Home  |  Disease Home  |  Microbes A to Z  |  Bio 203 Home


Serratia marcesens          Serratia colonies

What you should know:

Serratia are Gram-negative rods belonging to the Enterobacteria. They are common to soil, water, and mammals. S. marcescens is an opportunistic pathogen in humans and is easily recognized by its large, red-pigmented colonies when grown at less than 35C. At 37C, however, the genes for making the red pigment prodigiosin are turned off.


gamma-proteobacteria (volume 2)

Type species

Serratia marcescens

Facultative anaerobe, respiratory and fermentative metabolism, oxidase-negative, catalase-positive, H2S-negative, indole-negative, citrate-positive, casease-positive, DNAse-positive, amylase-negative, non-motile, nitrate-negative