Some of The world’s deadliest bacteria seek and feed on human blooda newly discovered phenomenon that researchers call “bacterial vampirism”. A team led by researchers from Washington State University (WSU) discovered that bacteria are attracted to liquid part of the blood, or serum, which contains nutrients they can use as food.
Some of the bacteria that most commonly cause infections in the bloodstream detect a chemical substance in human blood and “swim” towards it.
According to what was revealed by the website EurekAlert!one of the chemicals that seemed to especially attract bacteria was serine, an amino acid present in human blood which is also a common ingredient in protein drinks. The results of this investigation were published in the journal eLife on April 16th. Arden Baylink, professor at the WSU College of Veterinary Medicine and one of the authors of the research, said: “The bacteria that infect the bloodstream can be lethal“.
Baylink and the study’s lead author, WSU PhD student Siena Glenn, found that at least three types of bacteria, Salmonella enterica, Escherichia coli It is Citrobacter koseriare attracted to human serum. These bacteria are one of the main causes of death for people suffering from inflammatory bowel diseases (IBD), around 1% of the population. These patients usually present intestinal bleeding which can be the entry point for bacteria into the bloodstream.
Chemical attraction
As a highlight of the study, researchers determined that Salmonella has a special protein receptor called Tsr, which allows it to bacteria detect the serum and ‘swim’ towards it. Using a technique called protein crystallography, they were able to see the atoms in the protein that interact with serine. Scientists believe that the serine is one of the chemicals in the blood that bacteria detect and consume.
“By learning how these bacteria are able to detect blood sources, In the future we may be able to develop new drugs that block this ability. These medicines can improve the lives and health of people with IBD who are at high risk of bloodstream infections,” Glenn told EurekAlert!.
Scientists from the University of Oregon also participated in the research, and it was funded by WSU and the United States National Institute of Allergy and Infectious Diseases (NIAID). Glenn indicated that “this chemical that is in our blood and that we use as food is also something that these pathogenic bacteria recognize as food.” Hence the term “bacterial vampirism”, which explains this feeding process of some bacteria attracted to human blood.
Priority pathogens
To the bacteria analyzed by researchers are called pathogens Enterobacteriaceae multi-resistant and the World Health Organization (WHO) has labeled them “priority pathogens“. These pathogens belong to a group of 12 bacterial families considered the most important threat to human health due to their antibiotic resistancedeclared the WHO.
Enterobacteriaceae can also be “opportunistic pathogens that cause different types of infectionssuch as urinary tract infections, pyelonephritis, sepsis, pneumonia and meningitis”, according to Health Canada. Baylink explained to Global News that people with dinflammatory bowel diseases (IBD), such as Crohn’s disease and ulcerative colitis, are especially vulnerable to these bacteria, which normally reside in the intestine.
For their work, the researchers used a high-powered microscope and simulated an intestinal hemorrhage by injecting microscopic amounts of human serum and observing how the bacteria navigated toward the source. “Bacteria are microscopic organisms that have neither eyes nor ears. But they do have something analogous to smell. The sense of smell that bacteria possess is a behavior called chemotaxis. One of the main functions of chemotaxis is the search for food.“, explains Baylink.
News reference:
Glenn, S.J. et al. Bacterial vampirism mediated through taxis to serum. eLife, 2024.
