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 freelance 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

July 29 • 10:29 AM

How Textbooks Have Changed the Face of War

War is more personal, less glorious, and more hellish in modern textbooks than in the past. But there’s still room for improvement.


July 29 • 10:00 AM

The Monolingual American: Why Are Those Outside of the U.S. Encouraging It?

If you are an American trying to learn German in a large German town or city, you will mostly hear English in return, even when you give sprechen your best shot.


July 29 • 8:00 AM

The Elusive Link Between Casinos and Crime

With a study of the impact of Philadelphia’s SugarHouse Casino, a heated debate gets fresh ammunition.


July 29 • 6:00 AM

What Are the Benefits of Locking Yourself in a Tank and Floating in Room-Temperature Saltwater?

After three sessions in an isolation tank, the answer’s still not quite clear.


July 29 • 4:00 AM

Harry Potter and the Battle Against Bigotry

Kids who identify with the hero of J.K. Rowling’s popular fantasy novels hold more open-minded attitudes toward immigrants and gays.


July 29 • 2:00 AM

Geographic Scale and Talent Migration: Washington, D.C.’s New Silver Line

Around the country, suburbs are fighting with the urban core over jobs and employees.


July 28 • 4:00 PM

Border Fences Make Unequal Neighbors and Enforce Social Inequality

What would it look like if you combined Israel, the West Bank, and Gaza, demographically speaking? What about the United States and Guatemala?


July 28 • 2:00 PM

Are Patient Privacy Laws Being Misused to Protect Medical Centers?

A 1996 law known as HIPAA has been cited to scold a mom taking a picture of her son in a hospital, to keep information away from police investigating a possible rape at a nursing home, and to threaten VA whistleblowers.


July 28 • 12:00 PM

Does Internet Addiction Excuse the Death of an Infant?

In Love Child, documentary filmmaker Valerie Veatch explores how virtual worlds encourage us to erase the boundary between digital and real, no matter the consequences.


July 28 • 11:11 AM

NASA Could Build Entire Spacecrafts in Space Using 3-D Printers

This year NASA will experiment with 3-D printing small objects in space. That could mark the beginning of a gravity-free manufacturing revolution.


July 28 • 10:00 AM

Hell Isn’t for Real

You may have seen pictures of the massive crater in Siberia. It unfortunately—or fortunately—does not lead to the netherworld.


July 28 • 8:00 AM

Why Isn’t Obama More Popular?

It takes a while for people to notice that things are going well, particularly when they’ve been bad for so long.


July 28 • 7:45 AM

The Most Popular Ways to Share Good and Bad Personal News

Researchers rank the popularity of all of the different methods we have for telling people about our lives, from Facebook to face-to-face.


July 28 • 6:00 AM

Hams Without Ends and Cats Tied to Trees: How We Create Traditions With Dubious Origins

Does it really matter if the reason for why you give money to newlyweds is based on a skewed version of a story your parents once told you?


July 28 • 4:00 AM

A Belief in ‘Oneness’ Is Equated With Pro-Environment Behavior

New research finds a link between concern for the environment and belief in the concept of universal interconnectedness.


July 25 • 4:00 PM

Flying Blind: The View From 30,000 Feet Puts Everything in Perspective

Next time you find yourself in an airplane, consider keeping your phone turned off and the window open.


July 25 • 2:00 PM

Trophy Scarves: Race, Gender, and the Woman-as-Prop Trope

Social inequality unapologetically laid bare.


July 25 • 1:51 PM

Confusing Population Change With Migration

A lot of population change is baked into a region from migration that happened decades ago.


July 25 • 1:37 PM

Do Not Tell Your Kids That Eating Vegetables Will Make Them Stronger

Instead, hand them over in silence. Or, market them as the most delicious snack known to mankind.



July 25 • 11:07 AM

The West’s Groundwater Is Being Sucked Dry

Scientists were stunned to discover just how much groundwater has been lost from beneath the Colorado River over the past 10 years.


July 25 • 10:00 AM

Shelf Help: New Book Reviews in 100 Words or Less

What you need to know about Bad Feminist, XL Love, and The Birth of Korean Cool.



July 25 • 8:00 AM

The Consequences of Curing Childhood Cancer

The majority of American children with cancer will be cured, but it may leave them unable to have children of their own. Should preserving fertility in cancer survivors be a research priority?


July 25 • 6:00 AM

Men Find Caring, Understanding Responses Sexy. Women, Not So Much

For women looking to attract a man, there are advantages to being a caring conversationalist. But new research finds it doesn’t work the other way around.


Follow us


Subscribe Now

How Textbooks Have Changed the Face of War

War is more personal, less glorious, and more hellish in modern textbooks than in the past. But there’s still room for improvement.

NASA Could Build Entire Spacecrafts in Space Using 3-D Printers

This year NASA will experiment with 3-D printing small objects in space. That could mark the beginning of a gravity-free manufacturing revolution.

The Most Popular Ways to Share Good and Bad Personal News

Researchers rank the popularity of all of the different methods we have for telling people about our lives, from Facebook to face-to-face.

Do Not Tell Your Kids That Eating Vegetables Will Make Them Stronger

Instead, hand them over in silence. Or, market them as the most delicious snack known to mankind.

The West’s Groundwater Is Being Sucked Dry

Scientists were stunned to discover just how much groundwater has been lost from beneath the Colorado River over the past 10 years.

The Big One

One in two full-time American fast-food workers' families are enrolled in public assistance programs, at a cost of $7 billion per year. July/August 2014

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