September 14, 2010

Antibiotics Disrupt Good Bacteria Inside Stomach

U.S. researchers reported on Monday that antibiotics can disrupt the balance of microbes living inside the stomach.

A study found that the drug ciprofloxacin suppressed entire populations of beneficial bacteria.

The study, which consisted of three women, supports the common wisdom that antibiotics can damage the "good" germs living in the body.

It may also support the idea of developing probiotic products like yogurt with live cultures of bacteria.

The researchers tested the women by giving them a five-day course of the antibiotic ciprofloxacin twice during the 10-month study.

The team ran DNA tests on stool samples from volunteers in order to try and determine which microbes were living inside the stomach.

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

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

Other studies have also found that 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.

Microbes inside the stomach can affect obesity and may play a role in allergy.  Other researchers have found that Lactobacillus reuteri, which is found in breast milk, may protect against rotavirus infections.

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

The Stanford team wrote that regularly wiping out the body's bacterial population could also be helping to drive the rapid spread of drug-resistant superbugs.

"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.


On the Net: