Jumping between host species may be easier for bacteria than previously thought

Date: Feb-18-2015Researchers who studied a strain of bacteria that is responsible for

widespread epidemics in the global rabbit farming industry, have discovered just a

simple genetic mutation is all that separates it from a strain that also infects

humans.

A single genetic mutation enabled a human-specific bacterium to

jump to rabbits 40 years ago.

The team - from the Universities of Glasgow and Edinburgh in Scotland - believes

the discovery has major implications for how we assess the risks of bacterial

diseases that can pass between humans and other animals.

The study - reported in Nature Genetics - suggests bacteria may

be able to jump between host species more easily than we previously

thought.

In their paper, the scientists describe how they traced the evolution of the bacterium Staphylococcus

aureus ST121 in rabbits, where it can cause serious skin infections.

In humans, ST121 is found in the respiratory tract and on the skin of some

people. It is usually harmless, but it can lead to a range of

conditions - from minor infections to meningitis and sepsis.

One genetic change caused human-specific bacteria to jump to rabbits

In their study, the team found that rabbit-specific ST121 "evolved

through a likely human-to-rabbit host jump over 40 years ago," and that only a

single, naturally occurring mutation was all that was required.

The team believes theirs is the first study to report a single mutation is

sufficient to alter the host species of a pathogen during its evolution and to

highlight the capacity for disease-causing microorganisms to "readily expand into

new host species populations."

Co-author Jose Penades, a professor in the Institute of Infection, Immunity and

Inflammation at the University of Glasgow, adds:

"Our results represent a paradigm shift in understanding of the

minimal adaptations required for a bacterium to overcome species barriers and

establish in new host populations."

Fellow co-author Ross

Fitzgerald, a professor in the Centre for Infectious Diseases and of the Roslin

Institute at the University of Edinburgh, says the finding has important implications that "will require a re-examination of the future threat posed by bacterial host-switching events."

He notes that the potential seriousness of the finding is highlighted by

the increasing opportunities for cross-species transmission in domestic, industrial

and agricultural situations in a globalized world.

Meanwhile, Medical News Today recently learned of a study of mice that

showed individuals can inherit bacterial DNA from

their mothers in the womb. Writing in Nature, the researchers say

influences on immunity and inflammation can also be passed to offspring through

this mechanism.

Written by Catharine Paddock PhD

Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.