Gram stain: negative Cell shape: bacillus Arrangement: Oxygen requirements: facultative anaerobe Motility: motile Other: Produces red pigment at room temperature.
Habitat: Occurs naturally in soil and water as well as the intestines.
Pathogenicity: Important as a nocosomial infection; associated with urinary and respiratory tract infections, endocarditis, osteomyelitis, septicemia, wound infections, eye infections, meningitis.
Transmission: direct contact, droplets; has been found growing on catheters, in saline irrigation solutions, and in other supposedly sterile solutions.
Treatment: Includes cephalosporins, gentamicin, amikacin, but most strains are resistant to several antibiotics because of the presence or R-factors on plasmids.
We used to think that this bacteria was non-pathogenic, and because of the pigment it produces, it was used widely to trace bacterial transmission. In 1951 and 1952 the US Army conducted a study called "Operation Sea-Spray" to study wind currents that might carry biological weapons. They filled balloons with S. marcescens and burst them over San Francisco. Shortly thereafter, doctors noted a drastic increase in pneumonia and urinary tract infections.
Serratia marcescens
