Antibiotics mess up your stomach, U.S. study finds

WASHINGTON Mon Sep 13, 2010 7:05pm EDT

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WASHINGTON (Reuters) - Even seemingly gentle antibiotics may severely disrupt the balance of microbes living in the gut, with unforeseen health consequences, U.S. researchers reported on Monday.

An intimate study of three women given ciprofloxacin showed the drug suppressed entire populations of beneficial bacteria, and at least one woman took months to recover.

The study, published in the Proceedings of the National Academy of Sciences, supports the common wisdom that antibiotics can damage the "good" germs living in the body.

It may also support the idea behind the development of so-called probiotic products including yogurt with live cultures of bacteria.

The researchers tested the three volunteers daily, giving them a five-day course of the commonly used antibiotic ciprofloxacin twice during the 10-month study.

They ran DNA tests on stool samples from the volunteers to determine what kind of microbes were living in the gut.

"The effect of ciprofloxacin on the gut microbiota was profound and rapid," Les Dethlefsen and David Relman of Stanford University in California wrote.

"By one week after the end of each course, communities began to return to their initial state, but the return was often incomplete."

More and more studies support the idea that humans and other animals have a symbiotic relationship with germs. Microbes in the intestines help digest food and "good" germs can take up space and keep bad germs away.

"The human distal gut is one of the most complex ecosystems on the planet," the researchers wrote in the study, available here

Gut microbes can affect obesity and may play a role in allergy. Lactobacillus reuteri, found in breast milk, may protect against rotavirus infections, other researchers have found.

Several recent studies have found that certain bacteria cause inflammation that can affect appetite as well as inflammatory bowel conditions like Crohn's disease and colitis.

Regularly wiping out the body's bacterial population could also be helping drive the rapid spread of drug-resistant superbugs, the Stanford team said.

"One potential ramification of the altered community is an enhanced carriage of antibiotic-resistance genes in the human population," they wrote.

"Every course of antibiotics may represent another roll of the dice," they added -- potentially a "bad" strain to replace a beneficial species.

(Reporting by Maggie Fox; Editing by Cynthia Osterman)

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Comments (3)
Terry5003 wrote:
That is why they are called antibiotics because they kill microbes? So far none have been developed to kill only the microbes that are the problem they kill a wide variety. Good and bad.
This was discovered many years ago.
I wonder if this was a government research project that we the taxpayers paid for?

Sep 14, 2010 6:04pm EDT  --  Report as abuse
Sigh please spend money on isolating and cataloguing the millions of microbes in the average stomach as its blatantly obvious that they have a major effect on the health of anyone, if you dont put in the work you can hardly be supprised when evolution bumps you off.

Sep 14, 2010 8:26pm EDT  --  Report as abuse
jmmx wrote:
Gee – the Natural Foods community has been saying this for years. Correction – for DECADES. I first heard this over 30 years ago. I am not one who believes everything I hear or read, but this made absolute sense.

Nice to see that the medical profession is finally catching up.

BTW: Nancy’s Yogurt of Springfield Oregon is the best! (No I have no financial interest in them.)

Sep 15, 2010 2:16am EDT  --  Report as abuse
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