Stomach Bug that you even know about

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Twenty years ago, in a report published in the prestigious British medical journal The Lancet, scientists from Australia announced that they had isolated a microorganism that lives on the thick mucus lining of the stomach. They theorized that the bacterium might play a role in chronic active gastritis, a persistent inflammation of the stomach.

Over the next two decades, research into the bacterium named Helicobacter pylori, or H. pylori led to a new era in gastrointestinal medicine. The bacterium was found in the stomachs of more than half the world’s population 70% to 90% in developing countries, and about 30% in the US. H. pylori also were discovered to be a leading cause of ulcers and stomach cancer.

These days, a doctor who finds a patient infected with H. pylori attempts to eradicate it. But is that treatment always helpful? Or, as newer studies suggest, is the eradication of H. pylori creating an unexpected and unprecedented epidemic of diseases of the esophagus, the tube that connects the back of the throat to the stomach?

To answer these and other questions, we spoke to Martin J. Blaser, MD, a renowned authority on H. pylori.

• Billions of people worldwide are infected with H. pylori. Is this a normal condition or a disease?

The most recent evidence strongly suggests that H. pylori was once even more common than it is now, perhaps found in everyone. In other words, it is probably a normal part of the bacterial environment, or flora, of the stomach, much like the so-called friendly bacteria in the intestines.

Our industrial, postmodern society is not conducive to H. pylori. Studies show that in populations that have better hygiene and sanitation as well as smaller families, there is a lower incidence of colonization with H. pylori. (Scientists don’t know exactly how the bacterium spreads from person to person.) With the widespread use of antibiotics and the concerted efforts of physicians to remove H. pylori from large numbers of people, the bacterium is disappearing in developed countries, particularly in the US.

• Is the disappearance of H. pylori a positive development?

Yes and no. Everybody who has the organism has a condition called chronic superficial gastritis a mild inflammation of the stomach that has no symptoms. However, having that condition increases the risk of developing an ulcer by approximately three- to fourfold and stomach cancer by tenfold.

This is especially true for people who carry a strain of the bacterium called CagA+, one of a number of types of H. pylori. Where H. pylori are disappearing, ulcers and stomach cancer are disappearing as well. And that’s good. More and more cases of ulcers are being caused by the chronic intake of non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen (Advil).

But as these diseases have gone away, other diseases have become more common particularly gastrointestinal reflux disease (GERD), commonly referred to as heartburn. In some people, GERD leads to a condition called Barrett’s esophagus (abnormal changes in the cells lining the esophagus), which in turn can lead to esophageal cancer.

In the US, the rate at which esophageal cancer is increasing is one of the fastest for all malignancies. The same is true in other developed countries, such as England, Norway and Australia.

• Why would a decrease in H. pylori cause an increase in GERD and esophageal cancer?

With aging, there is a normal diminution in the production of stomach acid. Eradicating the CagA+ strain of H. pylori creates a biochemical process that allows the stomach to generate full levels of acid, even at age 50 and older. And it’s the regurgitation of stomach acid into the esophagus that causes GERD.

Additionally, studies show that there is an inverse relationship between the level of the CagA+ strain of H. pylori and esophageal cancer those without CagA+ have a four- to five fold higher risk of developing esophageal cancer.

• In light of these findings, who should be treated for H. pylori?

If somebody has an ulcer, there is no question getting rid of H. pylori. The benefits far outweigh the risks. And if someone has a rare form of stomach cancer called gastric lymphoma, eradicating H. pylori is a standard part of treatment.

Otherwise, there is no reason to remove the bacteria even though removing it, in cases of indigestion, is standard practice for many physicians. H. pylori are not a pathogen. Studies show that removing it does not improve the symptoms of indigestion.

New studies show that the stomachs of people who have H. pylori produce more leptin, a hormone that inhibits appetite. As H. pylori are being eradicated, obesity is increasing. Is there a link? Many scientists think this is a possibility.

• If a person should be treated for H. pylori, what is the best method?

The best therapy is the simultaneous use of three or four medications, usually two antibiotics, such as amoxicillin (Amoxil), metronidazole (Flagyl), tetracycline (Achromycin V) or clarithromycin (Biaxin), an acid inhibitor (such as a protonpump inhibitor or H2-blocker) and/or bismuth salts. The use of this combination regimen for seven to 10 days has eradication rates of higher than 90%.

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