Scientists discovered 'vampire' bacteria that thirst for human blood

American scientists have discovered a new vampire-like characteristic of some bacteria, which is to hunt and consume human blood .

For a long time, scientists have not been able to explain why bacteria such as Salmonella and E. coli can move from the intestines into the blood, and then cause death in some cases.

A sample of E. coli bacteria. (Photo: University of Giessen (Germany)).

Recently, a research team at the University of Washington (USA) discovered that these bacteria are attracted to the liquid part of the blood (serum) , which contains nutrients that the bacteria consider food.

They can easily 'smell' the location of the serum and enter the bloodstream through small scratches in the digestive system. Even the smallest amount of blood is enough to attract 'vampire bacteria', just as sharks can detect blood in water.

Study co-author, Professor Arden Baylink said: ' Bacteria infecting the blood can be deadly. We found that some bacteria that commonly cause blood infections can sense a chemical in human blood and swim towards it.'

The research results were published in the journal eLife. Accordingly, intestinal bacteria such as E. coli and Salmonella can detect even just 1 femtoliter of serum - a very small unit of measurement equivalent to 0.0000000000001 ml. When they discover a scratch that is leaking blood into the intestines, they will surround and enter.

The team monitored the bacteria's search for serum and found that it took less than a minute. In this case, the bacteria rely on chemotaxis and move to where the substances are in higher concentration.

This new research into how bacteria enter the bloodstream paves the way for advanced drugs that can prevent sepsis before it occurs, scientists say.

Under normal circumstances, there are populations of bacteria in the gut that are generally considered harmful such as E. coli and salmonella. When healthy, other bacteria and our immune system keep these bacteria in check. But if these bacteria get into the bloodstream, they can lead to sepsis.