Hospital superbug MRSA was triggered by hedgehogs

By Mark Waghorn via SWNS

Hospital superbug MRSA was triggered by hedgehogs, according to new research.

It arose in the prickly little mammals more than 200 years ago - long before clinical use of antibiotics.

The discovery sheds fresh light on one of the world's biggest threats to health.

Humans and livestock have speeded its course - but were not the originators.

"Our study suggests it wasn't the use of penicillin that drove the initial emergence of MRSA - it was a natural biological process,"said senior author Dr. Ewan Harrison, of Cambridge University.

"We think MRSA evolved in a battle for survival on the skin of hedgehogs - and subsequently spread to livestock and humans through direct contact."

But it is not a reason to fear the charismatic creatures. They carry a form called mecC-MRSA that rarely infects people.

An international team tracked the deadly bacteria's genetic history after surveys in Denmark and Sweden detected it in up to 60 percent of hedgehogs.

"Using sequencing technology we have traced the genes that give mecC-MRSA its antibiotic resistance all the way back to their first appearance. We found they were around in the 19th century," Harrison said.

Humans and livestock have traditionally been blamed for the emergence of MRSA (methicillin-resistant staphylococcus aureus).

But resistance to antibiotics is not a modern phenomenon. It has existed for centuries. Almost all those we use today arose in nature.

Overuse will favor the strongest strains. It's only a matter of time before they start to lose effectiveness.

"This study is a stark warning that when we use antibiotics, we have to use them with care,"said senior author Professor Mark Holmes, also from Cambridge.

"There's a very big wildlife 'reservoir' where antibiotic-resistant bacteria can survive.

"From there it's a short step for them to be picked up by livestock - and then to infect humans."

It illustrates the role of natural selection in the evolution of antibiotic resistance in disease-causing bacteria, said the researchers.

They isolated more than 1,000 strains of S. aureus from hedgehogs and other sources.

The analysis revealed certain lineages of MRSA appeared in European hedgehogs by the early 1800s - before spreading to cattle and humans.

It was not until 1928 penicillin, the first true antibiotic, was discovered by Scots born Alexander Fleming at St Mary's Hospital in London.

Hedgehogs are frequently colonized with a fungal parasite called Trichophyton erinacei that naturally produces its own antibiotics.

Living side by side, the bacteria evolved antibiotic resistance in response to the skin fungus. It causes 1 in 200 MRSA infections in humans.

"It's widely thought the emergence of antibiotic resistance in bacteria was driven by the clinical use of antibiotics," Harrison said.

"This study suggests that hedgehogs had a primary role in at least some of the current antibiotic-resistant bacterial strains."

Misuse of antibiotics is now accelerating the process - with resistance rising to dangerously high levels globally.

Ten years ago Holmes and colleagues first identified mecC-MRSA in human and dairy cow populations.

At the time it was assumed the strain had arisen in the cows because of the large amount of antibiotics they are routinely given.

MRSA was first identified in patients in 1960. Due to its resistance to antibiotics, it's much harder to treat than other bacterial infections.

The World Health Organization says MRSA and other superbugs could return medicine to the "Dark Ages." They are also a major challenge in livestock farming.

"It isn't just hedgehogs that harbor antibiotic-resistant bacteria - all wildlife carries many different types of bacteria, as well as parasites, fungi and viruses," said Holmes.

"Wild animals, livestock and humans are all interconnected - we all share one ecosystem.

"It isn't possible to understand the evolution of antibiotic resistance unless you look at the whole system."

An estimated 30 percent of hedgehogs have disappeared over the past decade. There are now fewer than one million left in the UK.

They are facing extinction because of habitat loss, urban development and garden pest control - including slug pellets.

MRSA is carried harmlessly by one in three people. But it can prove fatal in the elderly or vulnerable - including newborn babies.

Drug-resistant diseases already kill 700,000 people a year - including 800 in Britain.

Experts fear the annual toll could hit 10 million by 2050 without more action. The study was published in the journal Nature.