Vampire bacteria: out for human bloodSome of the world’s deadliest bacteria seek out human blood to feed on.
A team of scientists, led by Washington State University (WSU) researchers, found that the bacteria are attracted to the liquid part of blood, or serum, which contains nutrients the bacteria can use as food.
“Bacteria infecting the bloodstream can be lethal,” said Arden Baylink, a WSU professor and the corresponding author for the research.
These patients often have intestinal bleeding that can be entry points for the bacteria into the bloodstream.
The response was rapid: it took less than a minute for the bacteria to find the serum.
Vampire bacteria: out for human blood
Some of the world’s deadliest bacteria seek out human blood to feed on. This newly discovered phenomenon has been named “bacterial vampirism”.
A team of scientists, led by Washington State University (WSU) researchers, found that the bacteria are attracted to the liquid part of blood, or serum, which contains nutrients the bacteria can use as food. One of the chemicals bacteria seemed to be drawn to was serine, an amino acid that is also a common ingredient in protein drinks. This finding, published in the journal eLife, provides new insights into bloodstream infections and their treatment.
“Bacteria infecting the bloodstream can be lethal,” said Arden Baylink, a WSU professor and the corresponding author for the research. “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 team found at least three types of bacteria, Salmonella enterica, Escherichia coli, and Citrobacter koseri, are attracted to human serum. These bacteria are a leading cause of death for people who have inflammatory bowel diseases. These patients often have intestinal bleeding that can be entry points for the bacteria into the bloodstream.
Using a high-powered microscope system called the chemosensory injection rig assay, the researchers simulated intestinal bleeding with microscopic amounts of human serum and watched as the bacteria navigated towards the source. The response was rapid: it took less than a minute for the bacteria to find the serum.
As part of the study, the researchers determined that Salmonella has a special protein receptor called Tsr that enables bacteria to sense and swim towards serum. Using crystallography, they were able to view atoms of the protein interacting with serine. “By learning how these bacteria are able to detect sources of blood, in the future we could develop new drugs that block this ability,” Siena Glenn, the lead author, said.
