Dynamics of the bacterial gut microbiota in preterm and term infants after intravenous amoxicillin/ceftazidime treatmentOriginal 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 study measured how the duration of intravenous amoxicillin/ceftazidime treatment affects gut microbiota development in newborns. Fecal samples were collected across the first six postnatal weeks. The V3-V4 region of the 16S rRNA gene was sequenced on the Illumina MiSeq platform. Differential abundance testing, redundancy analysis and correlation analysis linked microbiota composition to antibiotic duration and clinical factors such as delivery mode, feeding and gestational age.
Who was studied?
The cohort was 63 preterm and term infants born at 32 to 42 weeks gestation, admitted to a neonatal ward in Zwolle, the Netherlands. In total, 263 fecal samples were collected. Infants received either no antibiotics (control, n = 28), short-term treatment under three days (n = 22), or long-term treatment over five days (n = 13) during the first postnatal week. Samples were taken at postnatal weeks one, two, three, four and six.
What were the most important findings?
Antibiotics increased Enterococcus while decreasing Bifidobacterium and Streptococcus during the first two weeks. Overall composition was associated with treatment duration through the first three weeks. At week one, treated infants had lower Bifidobacterium (Log2 fold change around -7.5, p = 0.0003 for short-term) and higher Enterococcus. Enterococcus rose further after long treatment at week two (p = 0.005). Richness and diversity increased over time in all groups and depended on which taxon dominated, being lowest when Enterococcus dominated.
What are the greatest implications of this study?
The findings show early antibiotics reshape the neonatal gut, favoring enterococci over beneficial bifidobacteria and streptococci. Both short and long courses allowed restoration within six weeks. Longer treatment appeared to leave a more lasting mark, with Bifidobacterium recovery affected in more long-treated infants. The authors argue that this trade-off, and the possible link between disturbed early microbiota and later health, should factor into antibiotic prescribing decisions for newborns. Enterococcus could not be resolved to species level.