Antibiotics given early in life may have lasting negative effects

In mice, disruptions to the gut microbiome and behavioral issues lasted into adulthood.

70 percent of children in North America receive at least two courses of antibiotics by the time they are two years old. A new study adds to an emerging body of research suggesting that antibiotic use early in life could have lasting health effects. It found that mice exposed to antibiotics in the womb and after birth saw changes to their brains, gut microbiomes, and social behavior that lasted into adulthood. For mice that received a probiotic alongside the antibiotic, these problems were not as severe. While we don’t yet know if these effects apply to humans, the results highlight the need for more research on early-life antibiotics and their long-term impact. Senior author John Bienenstock, a molecular medicine specialist at McMaster University, tells us more:

ResearchGate: What treatment did the mice in your study receive?

John Bienenstock: Pregnant mice were treated with low-dose penicillin V (equivalent to a pediatric dose) in the last week before they gave birth, and the pups continued to receive antibiotic through to weaning. One group of mice received this same antibiotic dose for 12 hours and were given a probiotic called Lactobacillus for 12-24 hours. Male and female offspring were tested as adults, three to six weeks after cessation of treatment.

RG: How did the antibiotic impact the mice?

Bienenstock: Mice treated with antibiotic had significant changes in gut microbiota, and behavioral changes including less anxiety. Half of them showed significant aggression in social defeat experiments. Antibiotic-treated mice also showed significant changes in the frontal cortex, but not the hippocampus.

RG: What was the effect of the probiotic you administered alongside the antibiotic in some of the mice?

Bienenstock: It had a definite effect in lessening most of the negative outcomes we observed, especially the imbalance of gut bacteria and behavioral changes.

RG: How common is it for human children to be treated with antibiotics when they’re very young?

Bienenstock: Statistics from North America suggest that 70 percent of all children have received at least two courses of antibiotic before the age of two.

RG: What’s the likelihood that the negative effects you saw also apply to humans?

Bienenstock: We can only speculate, since these experiments were conducted in mice. There are some early epidemiological-type studies suggesting that certain common psychiatric conditions are more prevalent if extensive antibiotic consumption occurred in early life. But there is no information as to whether there might be a correlation with the infections for which the antibiotic was given, or whether a specific antibiotic has greater association with potential incidence of anxiety or depression.

RG: What are the next steps in your research?

Bienenstock: We need to establish whether the same effects are seen if the antibiotic is administered only in pregnancy, or only to the pups after birth. The timing of the antibiotic late in pregnancy may be a crucial issue. This is a time when the fetus is undergoing rapid maturity of brain structure which may render it extremely sensitive to potentially noxious stimuli.

RG: What should the public take away from this study?

Bienenstock: These experimental results add to the list of concerns about the use and abuse of antibiotics in terms of long-term effects. Epidemiological studies in humans are suggesting that antibiotic use, and especially long-term use, may be associated with a number of gut conditions including celiac disease, inflammatory bowel disease, colorectal cancer and obesity. Our results as yet cannot be translated directly into the clinical arena. But they do flag the possible long-term negative effects, especially if given in early life, and identify the possibility that an appropriate probiotic taken twice a day may lessen such detrimental effects.

Featured image courtesy of eltpics.