Pylori Story #4: The Microbe Revolt

Could any life form survive in the stomach’s sizzling acid? Most thought there was no chance! And yet…there were occasional unexplained sightings…

 

Click above for previous installments of Pylori Story.

Stomach ulcers are miserable things. And not just because of their symptoms. Some of them will perforate – burn their way right through the stomach wall, causing bleeding that can be life-threatening. And some will lead to stomach cancer.

Helicobacter pylori, or H. pylori, has been causing peptic and other stomach ulcers in people for thousands of years at least. The oldest specimen found so far was reported this week: from the stomach of a 5,300 year-old mummy. But we didn’t know it was the culprit for both peptic ulcers and a lot of stomach cancer until pathologist Robin Warren formed his strong suspicions about what he was seeing in specimens – and his colleague Barry Marshall decided to lay his own uninfected stomach on the line to find out once and for all (publishing in 1985).

H. pylori is a helix- or S-shaped and straw-colored bacterium with the extraordinary ability to resist being harmed by acid. It moves with a corkscrew motion, propelled by its flagella – the 5 to 7 string-like appendages at one end. (A general introduction here, and more technical detail here.)

An increase in H. pylori infection associated with urbanization probably helped an ulcer epidemic take hold in the early 20th century (in people born before 1950). High rates of smoking and large-scale use of painkillers really kicked it along. About 10% of people in developed countries had peptic ulcers at the height of the epidemic. And because there weren’t very effective drugs yet, about 10% of those had operations to remove a part (or even all) of all their stomachs – a whopping 1% of adults!

At times, we were wrestling directly with H. pylori even though we didn’t realize it. Bismuth salts, the basis for the widely used antacid Pepto Bismol, turned out to be helping partly because it reduced H. pylori populations. And H. pylori infection could make drugs that reduce acid secretion a little more effective. We went off on various tangents about the cause of stomach ulcers – especially about diet and stress. (Read more about belief in stress as the cause of stomach ulcers below Pylori Story #1: Acid Attack.)

For a while, H. pylori eradication was suspected as the reason for a rise in gastric esophageal reflux disease (GERD), but it doesn’t seem to be after all. Some also thought that H. pylori was the only bacterium that could survive in the stomach. In 2006, though, Elisabeth Bik and colleagues identified a vast variety of microbes in the lining of the stomachs of healthy people.

H. pylori infection isn’t increasing – about half the people on the planet are estimated to be infected by them, with more advantaged people being infected less. But the effectiveness of therapy has been declining as H. pylori resistance to antibiotics grows. A multicenter study by the CDC from 1998 to 2002 found that just under 30% of the isolates of H. pylori they studied were resistant to at least 1 antibiotic – and 5% were resistant to 2 or more.

But now, studies of H. pylori isolates are showing around 70% of them are resistant to at least 1 antibiotic. And a recent study in Turkey found that nearly 20% of isolates there were resistant to multiple antibiotics. Resistance is developing more quickly in drugs used heavily in the region. For example, a recent study in Italy found around 70% resistance to clarithromycin, while in China, a study found a similar level,but to metronizadole.

So far, the rate of death from bleeding ulcers hasn’t been increasing along with the rise of antibiotic resistance. Combinations of drugs are still working though.

 

Read more about the weird and wonderful history of viewing the inside of the stomach in Pylori Story #2: Journey to the Center of the Stomach – with a detailed timeline below.

Pylori Story #3: Drug Wars – The Lab Strikes Back is about the development of drugs to suppress acid in the stomach.

Patient information and research about peptic ulcers.

 

Bibliography:

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Braden B. The best and worst treatments for Helicobacter pylori. BMJ 2015; 351: h4146.

Caliskan R, Tokman HB, Erzin Y, Saribas S, Yuksel P et al. Antimicrobial resistance of Helicobacter pylori strains to five antibiotics, including levofloxacin, in Northwestern Turkey. Rev Soc Bras Med Trop 2015; 48: 278-284.

Cappell MS, Wayne JD, Farrar JT, Sleisenger MH. Fifty landmark discoveries in gastroenterology during the past 50 years: a brief history of modern gastroenterology at the Millennium: Part I. Gastrointestinal procedures and upper gastrointestinal disorders. Gastroenterology Clinics of North America 2000; 29: 223-263.

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Marshall BJ, Armstrong JA, McGechie DB, Glancy RJ. Attempt to fulfil Koch’s postulates for pyloric Campylobacter. Med J Aust 1985; 142: 436-439.

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Zhang YX, Zhou LY, Song ZQ, Zhang JZ, He LH, Ding Y. Primary antibiotic resistance of Helicobacter pylori strains isolated from patients with dyspeptic symptoms in Beijing: a prospective serial study. World J Gastroenterol 2015; 21: 2686-2792.

 

The comic in this post is my own (CC-NC-ND-SA license). (More of my cartoons at Statistically Funny and on Tumblr.) With apologies for the lack of the resemblance to the actual people depicted!

 

* The thoughts Hilda Bastian expresses here at Absolutely Maybe are personal, and do not necessarily reflect the views of the National Institutes of Health or the U.S. Department of Health and Human Services.