Georgetown Study to Recruit Washington-area Children to Assess Probiotic to Prevent Diarrhea

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WASHINGTON (October 17, 2017) — Can a specific probiotic strain added to yogurt prevent diarrhea in children taking antibiotics for a common illness? That is what a new multimillion dollar study at Georgetown University Medical Center (GUMC) aims to investigate.

Probiotics, the “good bacteria” found in some foods and dietary supplements, have gained popularity as people have learned more about their suggested health benefits. Some studies have found that certain strains of bacteria can help treat or prevent a number of illnesses, such as traveler’s diarrhea, colic, inflammatory bowel disease, and diarrhea caused by antibiotics.

Up to 30 percent of people develop mild to severe diarrhea while taking antibiotics, and while previous studies (new window) have found that probiotics can help prevent it, there is not enough known about which strains are most effective, how they work or if a certain strain is more effective when taking a particular antibiotic.

To address this gap, a clinical trial led by researchers at GUMC will investigate whether a particular strain of bacteria added to yogurt is safe and prevents diarrhea in children who are receiving antibiotics to treat an upper-respiratory infection.

The phase 2 clinical trial is being funded by a five-year $3.1 million grant from the National Institute of Child Health and Human Development, which is part of the National Institutes of Health. It will treat the probiotic-supplemented yogurt as an “investigational new drug” as required by the U.S. Food and Drug Administration’s rules for substances that claim to improve a person’s health. The trial will begin enrolling patients in September.

“We know that after using antibiotics, we need to replenish good bacteria,” since antibiotics kill both good and bad bacteria in our bodies, said the study’s lead investigator, Dan Merenstein, MD, professor of family medicine at Georgetown University School of Medicine. “Now we’re trying to figure out which probiotics work, and to quantify it. It’s like we know exercise works, but if you can figure out which exercise works best and why, you can use it more effectively.”

The study will enroll 300 children and their parents. Half of the children will receive a strawberry yogurt drink that has two of the usual probiotic strains that are used to make milk into yogurt, plus a high dose of a third probiotic, Bifidobacterium lactis strain BB-12. The other half (the control group) will receive identical strawberry yogurt without the added BB-12. Both yogurts will be produced by Pennsylvania State University, which has its own dairy, to ensure the yogurt is consistent and meets the FDA quality control standards for drugs.

Merenstein said they chose to use yogurt because delivering the probiotics in a delicious drink has the potential to be more appealing, particularly to children, than delivering the same dose in a pill.

Not all beneficial bacteria can survive the stomach’s acidity, but BB-12 has been well-studied and is known to have that capability, Merenstein said. Both Merenstein’s lab and others have shown this to be true. This Bifidobacterium strain has also been found to be helpful in people who have chronic constipation by improving transit time, reducing bloating, and boosting people’s immune systems in general.

The study will also attempt to learn how antibiotics and probiotics affect the bacteria in the children’s intestines. Research colleagues at the University of Maryland will analyze the genetic makeup of bacteria found in the children’s stools during and after treatment to see which types are present and how they change over time.

“We’re still not sure how and why antibiotics disturb the gastrointestinal tract,” Merenstein said. “Even if our probiotic doesn’t work, we still might get a clue why from the microbiome analysis.”

Merenstein has served as an expert witness for General Mills, Nestle Healthcare and Bayer Healthcare on matters related to probiotics. He has also received travel funding for conference support from the International Scientific Association for Probiotics and Prebiotics.

The study is supported by the Eunice Kennedy Shriver National Institute of Child Health & Human Development (new window) of the National Institutes of Health (R01HD088428). 

More information about the study can be found on the study’s website (new window).

About Georgetown University Medical Center (new window)
Georgetown University Medical Center (GUMC) is an internationally recognized academic medical center with a three-part mission of research, teaching and patient care (through MedStar Health). GUMC’s mission is carried out with a strong emphasis on public service and a dedication to the Catholic, Jesuit principle of cura personalis — or “care of the whole person.” The Medical Center includes the School of Medicine and the School of Nursing & Health Studies, both nationally ranked; Georgetown Lombardi Comprehensive Cancer Center, designated as a comprehensive cancer center by the National Cancer Institute; and the Biomedical Graduate Research Organization, which accounts for the majority of externally funded research at GUMC including a Clinical and Translational Science Award from the National Institutes of Health.

Connect with GUMC on Facebook (new window) ( (new window)) and Twitter (new window) (@gumedcenter (new window)). Connect with Georgetown University School of Medicine on Facebook ( (new window)), Twitter (new window) (@gumedicine (new window)) and Instagram (new window) (@GeorgetownMedicine (new window)).