Short- and long-term impacts of azithromycin treatment on the gut microbiota in children: A double-blind, randomized, placebo-controlled trialOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
A randomized, double-blind, placebo-controlled trial tested whether short courses of azithromycin alter the gut microbiota of children aged 12 to 36 months. Children from the COPSAC2010 cohort had recurrent asthma-like episodes treated with a 3-day course of oral azithromycin or placebo.
How was it studied?
Fecal samples were collected 14 days after randomization (n = 59, short-term) and again at age 4 years (n = 49, long-term, including 18 placebo recipients). Microbiota composition was profiled by 16S rRNA gene amplicon sequencing.
What did they find?
Short-term, azithromycin reduced observed richness by 23 percent and Shannon diversity by 13 percent compared with placebo. The shift centered on the Actinobacteria phylum, with a notable reduction in the genus Bifidobacterium. At long-term follow-up, 13 to 39 months later, no differences remained between azithromycin and placebo groups.
Why it matters
A brief pediatric azithromycin course meaningfully disrupts gut microbiota diversity and Bifidobacterium abundance within two weeks. The disruption did not persist into later childhood, though the long-term placebo sample was small.