Septicaemia is an acute serious illness caused by bacterial infection of the blood. This is often a complication of local infection, such as pneumonia or pyelonephritis. Septicaemia may in turn result in the spread of infection to other sites, such as meningitis and osteitis.
Septicaemia may be caused by either Gram positive bacteria (such as Staphylococcus or Streptococcus) or Gram negative bacteria (such as E. coli or Klebsiella).
Gram described the method of staining bacteria blue and then dividing them into those bacteria that retained the stain (Gram positive) and those that lost the stain (Gram negative) when exposed to other chemicals. Gram positive bacteria usually live on the skin and in the upper respiratory tract while Gram negative bacteria normally live in the bowel. Rarely fungi can also cause septicaemia.