Some viruses, called bacteriophages, infect bacteria. A research team wanted to know more about bacteriophages that can infect Escherichia coli, a bacterium commonly found in the human gastrointestinal tract. Their work analyzed a variety of human clinical samples and revealed 43 bacteriophages, many of which were found in blood. While phages have been considered as a treatment for antibiotic-resistant infections, they can also spread resistance genes on to microbes. These findings, which have been reported in Frontiers in Microbiology, will help us learn more about the relationship between phages and the human body.
In the animation above, phages can be seen attacking E. coli.
"We examined 111 samples of blood, urine and other human body fluids to see if they contained phages. And we found them in almost one in seven samples," explained the first author of the study Dr. Cátia Pacífico, a scientist at Karl Landsteiner University of Health Sciences. "We also found a new kind of phage from the Tunavirinae subfamily. The presence of phages in so many samples and the discovery of a new form show just how little we know about phages in the human body."
Bacteriophages are not well known or understood, but they may play a critical role in the maintenance of the microbial population that all humans host. If we are to employ phages in the fight against antibiotic-resistant microbes, we have to learn more about how they impact various microbes.
"Increasing antibiotic resistance is a major problem that is growing worldwide, and we still know very little about the way in which phages contribute to this," said Pacífico.
This research looked specifically at bacteriophages that affect E. coli, which is a common cause of illness, especially bacterial infections acquired in hospitals. It revealed a surprising number of them, which seemed adept at combating E. coli.
"Almost two-thirds of the samples that contained phages against E. coli did not have any bacteria of this kind," noted the research leader, Prof. Friederike Hilbert of the Department for Farm Animals and Veterinary Public Health at the University of Veterinary Medicine Vienna. "This suggests that phages can also be transported from A to B without their host bacteria."
This research also revealed more about disinfectants that are used to destroy bacteria. "Our results showed that not all disinfectants are capable of reliably destroying phages," added Hilbert.
Learn more about how bacteriophages might be used as a therapeutic from the video above.