27 Jun 2022

Serratia marcescens

An aerobic gram-negative bacillus that grows readily on most microbiological media producing either a white, pink (pyrimine) or red (prodigiosin) colony. Pigment production occurs between 12oC and 36oC. Unlike prodigiosin, pyrimine is water soluble and is capable of diffusing into the medium, turning it pink. It is capable of growth at 40oC, but not at 4oC. It produces a fishy-urinary odor (trimethylalamine). It can be isolated from food, soil, water, plants, insects, and sewage. It is a potential pathogen for insects, animals, and humans and is an important cause of nosocomial (hospital-acquired) infections in humans.