Full evolutionary journey of the hospital superfig mapped for the first time

Modern hospitals and antibiotic treatment alone have not created all the antibiotic-resistant strains of bacteria we see today. Instead, selection pressures from before the widespread use of antibiotics influenced some of them to develop, new research has discovered.

Using analytical and sequencing technology that has just been developed in recent years, scientists from the Wellcome Sanger Institute, the University of Oslo and the University of Cambridge have created an evolutionary timeline of the bacterium Enterococcus faecalis, which is a common bacterium is resistant to antibiotics. infections in hospitals.

The results, published today in Nature communication shows that this bacterium has the ability to adapt quickly to selection pressures, such as the use of chemicals in farming, as well as the development of new medications, which have caused different strains of the same bacterium to be found in many places worldwide, from most people’s intestines for many wild birds. Because it is so widespread, the researchers suggest that people should be screened for this type of bacteria when they enter the hospital, in the same way as for other super lice, to reduce the possibility of the development and spread of infections in healthcare.

Enterococcus faecalis is a common bacterium that occurs in most people in the intestinal tract and does not harm the host. However, if someone is under pressure and this bacterium ends up in the bloodstream, it can cause a serious infection.

In hospitals, it is more common to find antibiotic-resistant strains of E. faecalis, and it was initially thought that the widespread use of antibiotics and other antibacterial control measures in modern hospitals led to the development of these strains.

In a new study, scientists from the Wellcome Sanger Institute, the University of Oslo and the University of Cambridge analyzed approximately 2,000 samples of E. faecalis from 1936 to the present day using bloodstream isolates from patients and faecal samples from animals and healthy people.

By arranging the genome (including chromosomes and plasmids) using the technology of Oxford Nanopore, the team mapped the evolutionary journey of the bacterium and created a timeline of when and where different strains develop, including those that nowadays offers resistance to antibiotics. They found that antibiotic-resistant strains developed earlier than previously thought, before the widespread use of antibiotics, and so it was not the use of antibiotics that gave rise to it.

Researchers have found that agricultural and early medical practices, such as the use of arsenic and mercury, have influenced the evolution of some strains. In addition, strains similar to the antibiotic-resistant variants we now see in hospitals have been found in wild birds. It shows how adaptable and flexible this species of bacterium is to develop into new strains in the face of various adversity.

Professor Jukka Corander, co-author and co-faculty member at the Wellcome Sanger Institute, said: “This is the first time we can map the full evolution of E. faecalis from specimens up to 85 years old, which enables us to “The detailed timeline of human lifestyles, agriculture and medicine on the development of different bacterial strains. The complete timeline of evolutionary changes would not have been possible without analytical and sequencing techniques found at the Sanger Institute.”

Dr Anna Pöntinen, co-lead author and postdoctoral fellow at the University of Oslo, said: “When patients are admitted to hospital, they are treated with antibiotic-resistant bacteria and fungi and isolated to ensure that infection rates are as low as Thanks to this study, it is possible to investigate the diversity of E. faecalis and to identify those who are more likely to spread within hospitals and thus cause harm to people with immune use.Also screen for E. faecalis at hospitalization. “

Professor Julian Parkhill, co-author and professor in the Department of Veterinary Medicine at the University of Cambridge, said: “This research has discovered that these strains of antibiotic-resistant bacteria are much older than we previously thought, and it has highlighted their incredible. metabolic flexibility combined with numerous mechanisms that improve their survival under difficult conditions, enabling them to spread widely throughout the world. ‘