Menus Subscribe Search

Quick Studies

EMpylori1.jpg

Helicobacter pylori. (Photo: Wikimedia Commons)

Evolutionary Explosions Help Bacteria Beat Immune Systems

• June 19, 2014 • 10:43 AM

Helicobacter pylori. (Photo: Wikimedia Commons)

Scientists have discovered bacteria evolving at a rate never before witnessed.

It’s been with humanity since before modern humans started to leave Africa, beguiling immune systems and stubbornly persisting in human stomachs for more than 60,000 years. It doesn’t always trigger illness, but, when it does, it can cause crippling stomach ulcers and gastritis.

When Helicobacter pylori invades a new host, it pulls off a frenetic feat of rapid-fire evolution that science is only just beginning to comprehend. It’s a bacterial trick that’s thought to have helped the widespread pathogen stay ahead of humans’ natural defense systemspossibly since humans became human.

A new H. pylori infection triggers an immune response that leads to stomach inflammation, attracting white blood cells to the stomach lining and releasing reactive nitrogen- and oxygen-based molecules. These molecules can trigger mutations in the bacterial genes, helping the species accelerate its rate of evolution as it comes under attack. And new research published in Nature Communications has revealed just how quickly the bacteria evolves during this initial battle.

“This extraordinarily fast mutation rate during the acute infection phase is the highest mutation estimate so far for any bacteria.”

Researchers somehow found two infected Australian volunteersboth naturally infected with H. pyloriwho were willing to be treated with potent antibiotic cocktails, then re-infected by drinking beef broth tainted with strains of the bacteria that were harvested from their own bodies prior to the antibiotic treatment. All the while, the volunteers were subjected to repeated endoscopies that sampled bacteria and checked for inflammation. That was certainly brave of the two volunteers, but the researchers would have preferred to have found more of them. So an unfortunate rhesus macaque was subjected to similar tests. The scientists analyzed the germ’s DNA at a laboratory in Pennsylvania to figure out how quickly it was mutating during different stages of infection.

During an initial evolutionary burst following a new infection, the bacterial DNA was found to mutate at 40 to 50 times the average rate at which it mutated during the subsequent chronic infection. All of the bacterial DNA mutated quickly during this evolutionary burst, but the changes manifested most prominently in the cell’s outer membrane proteins, helping them avoid detection by human defense cells. The mutation burst was detected both during the initial infections of the monkey and the re-infections of the human volunteers.

(Chart: Nature Communications)(Chart: Nature Communications)

“This extraordinarily fast mutation rate during the acute infection phase is the highest mutation estimate so far for any bacteria, exceeding the substitution rate in other bacterial species by at least two orders of magnitude,” the researchers write in their papernoting that similar experiments have not yet been conducted during the initial infection stages of other bacterial pathogens.

Bodo Linz, a research associate at Pennsylvania State University who was involved with the study, doesn’t expect these findings alone to lead to any new therapies. But he said the results could help do that in the long run.

“It’s basic research on which we can build for future studies,” Linz says. “We need to understand what’s going on before we can develop immune therapy or prevention.”

John Upton
John Upton is a science journalist with an ecology background. He has written recently for VICE, Slate, Nautilus, Modern Farmer, Grist, and Audubon magazine. He blogs at Wonk on the Wildlife. Upton's favorite eukaryotes are fungi, but he won't fault you for being human. Follow him on Twitter @johnupton.

More From John Upton

A weekly roundup of the best of Pacific Standard and PSmag.com, delivered straight to your inbox.

Recent Posts

September 16 • 4:00 PM

Why Is LiveJournal Helping Russia Block a Prominent Critic of Vladimir Putin?

The U.S. blogging company is showing an error message to users inside Russia who try to read the blog of Alexei Navalny, a prominent politician and critic of the Russian government.


September 16 • 2:00 PM

Man Up, Ladies! … But Not Too Much

Too often, women are asked to display masculine traits in order to be successful in the workplace.



September 16 • 12:00 PM

What Makes You So Smart, Brilliant 12-Year-Old?

Charles Wang is going to rule the world.


September 16 • 10:09 AM

No Innovation Without Migration: The Harlem Renaissance

The Harlem Renaissance wasn’t a place, but an era of migration. It would have happened even without New York City.


September 16 • 10:00 AM

A Law Professor Walks Into a Creative Writing Workshop

One academic makes the case for learning how to write.



September 16 • 7:23 AM

Does Not Checking Your Buddy’s Facebook Updates Make You a Bad Friend?

An etiquette expert, a social scientist, and an old pal of mine ponder the ever-shifting rules of friendship.



September 16 • 6:12 AM

3-D Movies Aren’t That Special

Psychologists find that 3-D doesn’t have any extra emotional impact.


September 16 • 6:00 AM

What Color Is Your Pygmy Goat?

The fierce battle over genetic purity, writ small. Very small.



September 15 • 4:00 PM

The Average Prisoner Is Visited Only Twice While Incarcerated

And black prisoners receive even fewer visitors.


September 15 • 2:00 PM

Gambling With America’s Health

The public health costs of legal gambling.


September 15 • 12:23 PM

The Scent of a Conservative

We are attracted to the body odor of others with similar political beliefs, according to new research.


September 15 • 12:00 PM

2014: A Pretty Average Election

Don’t get too worked up over this year’s congressional mid-terms.


September 15 • 10:00 AM

Online Harassment of Women Isn’t Just a Gamer Problem

By blaming specific subcultures, we ignore a much larger and more troubling social pathology.


September 15 • 8:00 AM

Atheists Seen as a Threat to Moral Values

New research attempts to pinpoint why non-believers are widely disliked and distrusted.


September 15 • 6:12 AM

To Protect Against Meltdowns, Banks Must Map Financial Interconnections

A new model suggests looking beyond balance sheets, studying the network of investment as well.


September 15 • 6:00 AM

Interview With a Drug Dealer

What happens when the illicit product you’ve made your living off of finally becomes legal?


September 15 • 4:00 AM

A Feeling of Control: How America Can Finally Learn to Deal With Its Impulses

The ability to delay gratification has been held up as the one character trait to rule them all—the key to academic success, financial security, and social well-being. But willpower isn’t the answer. The new, emotional science of self-regulation.



September 15 • 2:04 AM

No Innovation Without Migration: Do Places Make People?

We know that people make places, but does it also work the other way?


September 12 • 4:00 PM

Life, Liberty, and the Pursuit of Plastic Bags

California wants you to pay for your plastic bags. (FYI: That’s not an infringement on your constitutional rights.)


September 12 • 2:00 PM

Should We Trust the Hearts of White People?

On the 50th anniversary of the Civil Rights Act, revisiting a clip of James Baldwin on the Dick Cavett Show.


Follow us


3-D Movies Aren’t That Special

Psychologists find that 3-D doesn't have any extra emotional impact.

To Protect Against Meltdowns, Banks Must Map Financial Interconnections

A new model suggests looking beyond balance sheets, studying the network of investment as well.

Big Government, Happy Citizens?

You may like to talk about how much happier you'd be if the government didn't interfere with your life, but that's not what the research shows.

Give Yourself a Present for the Future

Psychologists discover that we underestimate the value of looking back.

In Soccer as in Art, Motifs Matter

A new study suggests a way to quantitatively measure a team’s style through its pass flow. It may become another metric used to evaluate potential recruits.

The Big One

One in three drivers in Brooklyn's Park Slope—at certain times of day—is just looking for parking. The same goes for drivers in Manhattan's SoHo. September/October 2014 new-big-one-3

Copyright © 2014 by Pacific Standard and The Miller-McCune Center for Research, Media, and Public Policy. All Rights Reserved.