Researchers at Washington State University have discovered a new behavior in bacteria such as Salmonella and E. coli, termed ‘bacterial vampirism’ or Vampire bacteria. These pathogens are known for causing foodborne illnesses.
For a long time, the mechanism through which these bacteria transition from the gut to the bloodstream, where they become highly dangerous, remained a mystery. Likewise, the reason for their migration was not understood.
According to the research team, these bacteria are drawn to blood or serum, which is rich in nutrients.
Scientists discovered that vampire bacteria are drawn to small amounts of blood
The bacteria are capable of tracking the location of the serum and can enter the bloodstream through minor abrasions in the digestive system. This can result in sepsis and potentially fatal outcomes, especially for individuals with inflammatory bowel disease.
Even a small amount of blood is enough to attract vampire bacteria, and it can detect a single drop of blood in 10 billion drops of water.
Arden Baylink, a professor at WSU’s College of Veterinary Medicine and co-author of the study, emphasized that “bacteria infecting the bloodstream can be lethal. We learned that some of the bacteria that most commonly cause bloodstream infections actually sense a chemical in human blood and swim toward it.”
The research, published in the journal eLife, revealed that enterobacteria such as E. coli and Salmonella can detect as little as 0.0000000000001 milliliters of serum.
Upon locating the source of the bleeding in the gut, where blood leaks into it, these bacteria gather at the site and invade it.
The researchers used an advanced microscope system to mimic intestinal bleeding by injecting minuscule amounts of human serum and watching how the bacteria navigate toward this source.
The observation showed that the bacteria detected the serum and moved toward it in under a minute. This behavior is referred to as ‘chemotaxis,’ where bacteria move toward higher concentrations of certain substances.
The study also identified that Salmonella possesses a specific protein receptor known as Tsr, which aids the bacteria in moving toward the serum.