Antibiotics are the most widely used drugs in childhood populations in Western countries, and antibiotic resistance is a growing public-health concern worldwide.
Now, new findings published in Nature Communications indicate that antibiotic use during childhood is associated with long-term changes in the composition, function, and antibiotic resistance of gut microbiota.
University of Helsinki researchers studied fecal samples from 142 children between ages 2 and 7. The control group of 43 children had not used antibiotics for more than two years and had a lifetime use of less than one course per year on average. The microbiota composition of other groups was compared with those of the control group. Fecal samples for the other groups were assigned based on antibiotic type and frequency during early life but not recently, within six to 12 months or 12 to 24 months of donation.
The researchers noticed clear differences in the gut microbiome of antibiotic-treated children. Antibiotics reduced the richness, or amount and variety, of bacterial species and slowed the age-driven microbiota development, particularly in kids who were dosed with macrolide antibiotics, broad-spectrum antibiotics often used to treat common bacterial infections, including ear infections and bronchitis. These include azithromycin (brand name Zithromax), clarithromycin (Klacid), erythromycin (Erymax, Erythrocin, and Erythroped), and others. The U.S. Centers for Disease Control and Prevention says that azithromycin is among the most commonly prescribed antibiotics.
“Penicillin-type antibiotics seemed to have a weaker impact on the composition and functioning of the microbiome than macrolides,” says lead researcher Katri Korpela, MSc.
The researchers also found that macrolide antibiotic use may alter the microbiota in infants in a way that predisposes them to weight gain and asthma in later childhood.
The results confirm prior research on mice that suggests antibiotics aren’t the direct cause of weight gain in later life, but because they alter or destroy the billions of beneficial bacteria in our guts that help to regulate our immune systems and prevent chronic disease, they make children more susceptible to these health risks.
Based on their findings, the researchers recommend avoiding macrolides as the primary antibiotic and advise restricting use of antibiotics to only times of genuine need, emphasizing they “should not be used to treat self-limiting infections and never ‘just in case.’”
More recently, findings from one study, published in Gastroenterology, also found that children who took three or more courses of antibiotics before the age of 2 were associated with an increased risk of early childhood obesity.
For more on beneficial gut bacteria, see “Good Bacteria Welcome” from our September 2011 issue.