An Interesting Indoor Microbe: Serratia marcescens

Name:  Serratia marcescens

Location: commonly found in showers, toilets, tiles etc.  Fairly ubiquitous in damp environments.

Description: rod-shaped, Gram-negative bacteria.  Often seen as a pink and slimy film on surfaces. Produces large amounts of red pigment.

Health concerns:  Relatively low health risk, but does cause nosocomial infections in hospitals.  Can also cause corneal infections by virtue of becoming established in contact lens cases.  The organism is extremely resistant to soaps and detergents, and in fact most hospital infections occur via contaminated cleaning solutions.

Cool facts:  The production of red pigment by Serratia is thought to be responsible for the miraculous bleeding of damp statues in the Middle Ages.  In the 1950’s the U.S. military released balloons containing (supposedly harmless) Serratia marcescens over San Francisco in order to simulate a bio-weapons attack. A number of people subsequently acquired serious infections and one patient died.  This organisms also can destroy saltwater corals.