Query: NC_020211:379000 Serratia marcescens WW4, complete genome
Lineage: Serratia marcescens; Serratia; Enterobacteriaceae; Enterobacteriales; Proteobacteria; Bacteria
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.
Subject: NC_005945:5202176 Bacillus anthracis str. Sterne, complete genome
Lineage: Bacillus anthracis; Bacillus; Bacillaceae; Bacillales; Firmicutes; Bacteria
General Information: This strain carries the anthrax toxin plasmid pXO1 but not the capsule plasmid pXO2 and is therefore avirulent but toxigenic. It is the counterpart to the Pasteur strain that carries pXO2 but not pXO1. This strain is often used for vaccine development. Under starvation conditions this group of bacteria initiate a pathway that leads to endospore formation, a process that is thoroughly studied and is a model system for prokaryotic development and differentiation. Spores are highly resistant to heat, cold, dessication, radiation, and disinfectants, and enable the organism to persist in otherwise inhospitable environments. Under more inviting conditions the spores germinate to produce vegetative cells. This organism was the first to be shown to cause disease by Dr. Louis Pasteur (the organism, isolated from sick animals, was grown in the laboratory and then used to infect healthy animals and make them sick). This organism was also the first for which an attenuated strain was developed as a vaccine. Herbivorous animals become infected with the organism when they ingest spores from the soil whereas humans become infected when they come into contact with a contaminated animal. PA/LF and PA/EF complexes are internalized by host cells where the LF (metalloprotease) and EF (calmodulin-dependent adenylate cyclase) components act. At high levels LF induces cell death and release of the bacterium while EF increases host susceptibility to infection and promotes fluid accumulation in the cells.