This confirms what researchers such as Dr. Martin Blaser (in his book Missing Microbes) and others (such as Drs. Sonnenburg and Sonnenburg) have been saying about antibiotic use in infants and children: that there are negative effects to the gut microbiome from antibiotic use in early childhood, and the more frequent the use, the greater the negative effects. It is because the use of antibiotics in early childhood "disrupts the microbiome".
Penicillins appear to be less disruptive, but macrolides (e.g., Clarithromycin, azithromycin) much more disruptive - the researchers found that the gut microbiota recovered within 6–12 months after a penicillin course, but did not fully recover from a macrolide course even after 2 years . Antibiotics can be life-saving, but they absolutely should not be used casually because there are hidden costs (such as microbiome changes). From Medical Xpress:
The use of antibiotics in early childhood interferes with normal development of the intestinal microbiota, shows research conducted at the University of Helsinki. Particularly the broad-spectrum macrolide antibiotics, commonly used to treat respiratory tract infections, have adverse effects. Macrolides appear also to contribute to the development of antibiotic-resistant strains of bacteria.
It is already known that early-life use of antibiotics is connected to increased risk of immune-mediated diseases such as inflammatory bowel disease, and asthma, as well as obesity. The effect is thought to be mediated by the intestinal microbes, since antibiotics in animal studies has been found to change the composition of the intestinal microbiota and reduce biodiversity.
The study, conducted at the University of Helsinki and led by Professor Willem de Vos, included 142 Finnish children, aged 2 to 7 years. Researchers investigated how many courses of antibiotics the children had received in their lifetime and how the use of antibiotics was reflected in their intestinal microbiota. In addition, they investigated the association between use of antibiotics and asthma and body mass index. The study is published in the scientific journal Nature Communications.
The results showed that children's intestinal microbiota composition clearly reflected the use of antibiotics. Antibiotics reduced the bacterial species richness and slowed the age-driven microbiota development. Particularly the microbiota of the children who had received macrolide antibiotics, such as azithromycin or clarithromycin, within the past two years differed from normal. The less time had passed since the macrolide course, the larger were the anomalies in the microbiota.
"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", says the researcher, Katri Korpela, whose doctoral thesis project includes the newly published research.
Macrolides appear to promote also the development of antibiotic resistance, as the resistance to these antibiotics was elevated in the microbiota of children who had used them."Penicillin-type antibiotics seemed to have a weaker impact on the composition and functioning of the microbiome than macrolides", Korpela says. The results support the recommendation to avoid macrolides as the primary antibiotic, and generally restrict the use of antibiotics to genuine need. Antibiotics should not be used to treat self-limiting infections and never 'just in case', the researchers emphasize.