Intestinal microbiome analysis demonstrates azithromycin post-treatment effects improve when combined with lactuloseOriginal 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?
This randomized controlled trial tested whether adding the prebiotic lactulose reduces the gut microbiome damage caused by the antibiotic azithromycin in children. It used a double-blind design. Investigators sequenced the 16S rRNA gene from stool samples taken before and after treatment. They compared children given azithromycin alone with those given azithromycin plus lactulose, tracking recovery of the gut microbial profile over time.
Who was studied?
The cohort was 87 children treated with azithromycin, with or without lactulose. The trial was double-blind and randomized, spanning preschool through adolescent ages. Gut microbial profiles were established at both the pre-treatment and post-treatment stages using stool 16S rRNA sequencing. The study was run by groups in Cyprus and Russia. The comparison was antibiotic alone versus antibiotic plus prebiotic.
What were the most important findings?
Azithromycin increased the relative abundance of opportunistic pathogens such as Streptococcus, an effect still evident 60 days after treatment. This shows a lasting disruption from the antibiotic alone. Children who also received lactulose showed higher relative abundance of saccharolytic bacteria within days, including Lactobacillus, Enterococcus, Anaerostipes, Blautia, and Roseburia. These genera appeared to protect against opportunistic pathogens. The azithromycin plus lactulose combination produced a phylogenetic profile more similar to the pre-treatment stage than azithromycin alone.
What are the greatest implications of this study?
The results suggest that pairing lactulose with azithromycin helps the gut microbiome return to balance faster by promoting beneficial saccharolytic microbes. This may limit colonization by opportunistic pathogens. The finding points toward antibiotic protocols designed to spare commensal bacteria. It offers a practical prebiotic co-treatment strategy. As a single trial in children, the durability and clinical benefit of this approach would need confirmation in larger studies.