Antibiotic use in early childhood interferes with normal development of the intestinal microbiota, according to researchers at the University of Helsinki, Finland, in the study “Intestinal microbiome is related to lifetime antibiotic use in Finnish pre-school children.” The article was recently published in the journal Nature Communications.

Early antibiotic use is associated with an increased risk of metabolic and immunological diseases such as inflammatory bowel disease (IBD), and mouse studies have indicated a causal role of the disrupted microbiome. However, little is known about the impact of antibiotics on the developing microbiome of children.

The study led by Professor Willem de Vos involved 142 children, ages 2 to 7 years, who were assessed as to the number of courses of antibiotics they had received in their lifetime and how such use was reflected in their intestinal microbiota. The team of researchers also examined the relationship between antibiotics, asthma, and body mass index (BMI).

Researchers found that the children’s intestinal microbiota composition reflected antibiotic use. Specifically, the antibiotics were found to reduce the richness of bacterial species and slowed the age-driven development of microbiota.

The microbiota of children treated with broad-spectrum macrolide antibiotics, including clarithromycin or azithromycin, within the previous two years particularly diverged from normal. The microbiota anomalies were also larger if less time had passed since the last macrolide course. These antibiotics are commonly used to treat respiratory tract infections.

“In general, it seems that the gut microbiota recovery from antibiotic treatment lasts more than a year. If a child gets repeated courses of antibiotics during their first years, the microbiota may not have time to fully recover,” said the study’s lead author Dr. Katri Korpela, in a university news release.

Macrolide use was related to microbiota features already associated with metabolic disease and obesity. A higher BMI was associated with macrolide use in a child’s first two years of life. Heavy use during those years also may have led to and asthma development later in life.

Macrolides also seemed to promote resistance to antibiotic treatment, as this resistance was high in the microbiota of children who had used them. In contrast, penicillin-type antibiotics “seemed to have a weaker impact on the composition and functioning of the microbiome than macrolides,” Korpela said.

Study results support the idea that, without compromising clinical practice, the impact on the intestinal microbiota should be considered when prescribing antibiotics to children.