Full evolutionary journey of hospital superbug mapped

Date:
March 9, 2021
Source:
Wellcome Trust Sanger Institute
Summary:
Researchers published the full genetic timeline of the bacterium,
Enterococcus faecalis showing the influence of human behaviour on
the development of different strains.



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


==========================================================================
By using analytical and sequencing technology that has only been developed
in recent years, scientists from Wellcome Sanger Institute, University of
Oslo and University of Cambridge have created an evolutionary timeline
of the bacterium, Enterococcus faecalis, which is a common bacterium
that can cause antibiotic resistant infections in hospitals.

The results, published today (9th March 2021) in Nature Communications
show that this bacterium has the ability to adapt very 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 the
majority of people's guts to many wild birds. As it is so widespread,
the researchers suggest people should be screened for this type of
bacteria when entering the hospital, in the same way they are for other superbugs, to help reduce the possibility of developing and spreading
infection within healthcare.

Enterococcus faecalis is a common bacterium that, in most people, is found
in the intestinal tract and doesn't cause harm to the host. However, if
someone is immunocompromised and this bacterium gets into 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 wide use of antibiotics
and other antibacterial control measures in modern hospitals caused
these strains to develop.

In a new study, scientists from Wellcome Sanger Institute, University
of Oslo and University of Cambridge analysed around 2000 samples of
E. faecalis from 1936 to present day using blood stream isolates from
patients and stool samples from animals and healthy humans.

By sequencing the genome (including chromosomes and plasmids) using
technology from Oxford Nanopore, the team mapped the evolutionary journey
of the bacterium and created a timeline of when and where different
strains developed, including those nowadays found to be resistant to antibiotics. They found that antibiotic resistant strains developed
earlier than previously thought, before the widespread use of antibiotics,
and therefore it was not antibiotic use alone that caused these to emerge.

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

Professor Jukka Corander, co-lead author and Associate Faculty member
at the Wellcome Sanger Institute, said: "This is the first time we have
been able to map out the full evolution of E. faecalis from samples
up to 85 years old, which enables us to see the detailed effect of
human lifestyles, agriculture and medicines on the development of
different bacterial strains. Having the full timeline of evolutionary
changes would not have been possible without analytical and sequencing techniques that can be found at the Sanger Institute." Dr Anna Po"ntinen, co-lead author and post-doctoral fellow at University of Oslo, said: "Currently, when patients are admitted to hospital, they are swabbed
for some antibiotic resistant bacteria and fungi and are isolated to
ensure that infection rates are kept as low as possible. Thanks to
this study, it is possible to scrutinize the diversity of E. faecalis
and identify those that are more prone to spread within hospitals and
thus could cause harm in immunocompromised people. We believe that
it could be beneficial to also screen for E. faecalis on admission
to hospitals." Professor Julian Parkhill, co-author and Professor in
the Department of Veterinary Medicine at University of Cambridge, said:
"This research has discovered that these hospital-associated strains
of antibiotic resistant bacteria are much older than we previously
thought, and has highlighted their incredible metabolic flexibility
combined with numerous mechanisms enhancing their survival under harsh conditions that has allowed them to spread widely across the globe." ========================================================================== Story Source: Materials provided by Wellcome_Trust_Sanger_Institute. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Anna K. Po"ntinen, Janetta Top, Sergio Arredondo-Alonso, Gerry
Tonkin-
Hill, Ana R. Freitas, Carla Novais, Rebecca A. Gladstone, Maiju
Pesonen, Rodrigo Meneses, Henri Pesonen, John A. Lees, Dorota
Jamrozy, Stephen D.

Bentley, Val F. Lanza, Carmen Torres, Luisa Peixe, Teresa M. Coque,
Julian Parkhill, Anita C. Schu"rch, Rob J. L. Willems, Jukka
Corander.

Apparent nosocomial adaptation of Enterococcus faecalis predates
the modern hospital era. Nature Communications, 2021; 12 (1) DOI:
10.1038/ s41467-021-21749-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/03/210309091248.htm

--- up 12 weeks, 7 hours, 57 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)