"Serratia" – genus of Gram-negative anaerobic rod-shaped bacteria, some species of which produce a red pigment, prodigiosin. Members of "Serratia" were initially considered harmless, however, they cause infections in animals, plants, humans, and insects. The diseases include pneumonia, meningitis, endocarditis, and wound infections. The most common species – "Serratia" "marcescens", was found to be highly pathogenic to humans and animals. "S. marcescens" is included in hospital-acquired infections; found in urinary, respiratory, and gastrointestinal tracts. They cause disease mainly in individuals with weak immune system. Other species cause bone and cardiovascular system infections. 