Researchers look at the positive and negative effects of giving penicillin and other antibiotics to children.

Antibiotics have been helping us to ward off infections for nearly a century, since the invention of penicillin in 1928.

An increasing number of studies, however, point to the adverse effects of administering penicillin to children early in life.

Nonetheless, a new study has examined the effect of a low dose of penicillin in late pregnancy and early life on the offspring of mice.

When Sir Alexander Fleming discovered penicillin – the world’s first antibiotic – in 1928, he revolutionized medicine.

Since then, penicillin has saved countless lives as the bacteria-killer has been used to fight a wide range of infectious diseases that, until then, were incurable and deadly.

Today, penicillin-based antibiotics are still widely prescribed. In fact, a 2010 study reported that amoxicillin was the most commonly dispensed drug among children around the world.

Recent studies, however, have been expressing concern over the long-term, negative effects of early-life exposure to penicillin.

Maternal intake of antibiotics has been linked with a risk of asthma in children. Early-life exposure in offspring has been associated with allergies, obesity, and neurocognitive impairment in late adulthood.

Researchers at St. Joseph’s Healthcare Hamilton and McMaster University – both in Ontario, Canada – set out to investigate the long-term effects of early-life exposure to penicillin in the offspring of mice.

The study was published in the journal Nature Communications.

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The researchers found that penicillin had long-lasting effects on offspring.

Specifically, the mice treated with antibiotics showed a lower level of anxiety-like behavior as well as higher levels of social aggression.

The antibiotics seemed to affect both sexes equally, altering the gut bacteria and increasing the expression of cytokines in the mice’s frontal cortex. Cytokines help to control the body’s immune response.

Additionally, the antibiotic was found to alter the integrity of the blood-brain barrier – a semipermeable membrane barrier that separates the blood circulating in our body from the brain fluid and tissue.

Dr. John Bienenstock, director of the Brain-Body Institute at St. Joseph’s Healthcare Hamilton and Distinguished Professor at McMaster University, explains the findings:

“In this paper, we report that low-dose penicillin taken late in pregnancy and in early life of mice offspring, changes behavior and the balance of microbes in the gut. While these studies have been performed in mice, they point to popular increasing concerns about the long-term effects of antibiotics. Furthermore, our results suggest that a probiotic might be effective in preventing the detrimental effects of the penicillin.”

The scientists discovered that a probiotic supplementation protects against some of these modifications. The Lactobacillus rhamnosus JB-1 was found to partially counteract the antibiotics’ effect.

However, the researchers concede that the sample size of the analyses for this was quite small, so the positive effects of the probiotic should be validated by further research.

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Bienenstock expressed concern over the widespread pediatric use of antibiotics.

“There are almost no babies in North America that have not received a course of antibiotics in their first year of life,” he told Healthline. “Antibiotics are not only prescribed, but they are also found in meat and dairy products. If mothers are passing along the effects of these drugs to their as yet unborn children or children after birth, this raises further questions about the long-term effects of our society’s consumption of antibiotics.”

In the near future, the researchers plan to investigate the effects of penicillin on offspring when administered only to pregnant mothers.

Additionally, the scientists hope to counter the negative behavioral effects of antibiotics with the help of beneficial bacteria, so they will test the efficacy of various bacteria in the offspring of mice.

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