DefinitionSepsis is a severe illness in which the bloodstream is overwhelmed by bacteria.Alternative NamesSystemic inflammatory response syndrome (SIRS)Causes, incidence, and risk factorsSepsis is caused by a bacterial infection that can begin anywhere in the body. Common places where an infection might start include:The bowel (usually seen with peritonitis)The kidneys (upper urinary tract infection) The liver or the gall bladderThe lungs (bacterial pneumonia)The skin (cellulitis)Sepsis may also accompany meningitis. In children, sepsis may accompany infection of the bone (osteomyelitis). In hospitalized patients, common sites of infection include intravenous lines, surgical wounds, surgical drains, and sites of skin breakdown known as bedsores (decubitus ulcers).The infection is often con