General Information: This organism was discovered in 1819 by Bizio who named the organism after the Italian physicist Serrati. It was considered a nonpathogenic organism until late in the 20th century, although pathogenicity was noted as early as 1913. Serratia marcescens is an opportunistic human pathogen that is increasingly associated with life-threatening hospital-acquired infections. It is an environmental organism that has a broad host range, and is capable of infecting vertebrates and invertebrates, as well as plants. In humans, Serratia marcescens can cause meningitis (inflammation of the membrane surrounding the brain and spinal cord), endocarditis (inflammation of heart muscle) and pyelonephritis (inflammation of the kidneys). Many strains are resistant to multiple antibiotics. Environmental isolates are noted by production of the red pigment prodigiosin.