Haiser, H. J. | Search bioRxiv

bioRxiv2026

Pharmacokinetics and Efficacy of the FimH Inhibitor Sibofimloc in Preventing Necrotizing Enterocolitis in Preterm Piglets

Necrotizing enterocolitis (NEC) is a disease in preterm infants associated with an increased abundance of Enterobacteriaceae. FimH, a mannose-binding adhesin on Enterobacteriaceae type 1 fimbriae, mediates mucosal attachment and TLR4-dependent inflammatory cascades. We evaluated the safety, pharmacokinetics, and efficacy of an oral FimH inhibitor (Sibofimloc) to reduce Enterobacteriaceae colonization and prevent NEC in preterm piglets. We performed a 9-d dose-escalation safety study (10, 25, 50 mg/kg BID) assessing absorption and tolerability and a 10-d randomized efficacy study. Piglets in the efficacy study received an infant formula diet with or without oral sibofimloc (40 mg/kg BID), or donor human milk (DHM) as a healthy control. NEC incidence, tissue histopathology, and gut microbiota composition via metagenomic whole-genome sequencing (WGS) were evaluated. Systemic exposure data reveal that sibofimloc was dose-dependently absorbed, while plasma levels decreased from postnatal day 2 to day 8, indicating reduced drug absorption with maturation of the intestinal barrier. Treatment with sibofimloc did not reduce NEC incidence (100% in sibofimloc in formula controls) or severity, whereas DHM-fed piglets experienced 0% NEC. Sibofimloc-treated animals exhibited significantly reduced crypt depths, demonstrating heightened mucosal injury and impaired regenerative capacity. WGS revealed that sibofimloc-treated animals maintained a gut luminal microbiota composition similar to untreated formula controls, dominated by Clostridium perfringens (C. perfringens). Selective targeting of FimH-expressing Enterobacteriaceae was insufficient to prevent NEC or alter the gut microbiota in this preterm piglet model, underscoring the complexity of NEC-associated microbial communities and suggesting that additional microbial targets and other colonization mechanisms may contribute to disease development.

microbiology↗

bioRxiv2018

Illuminating the microbiome’s dark matter: a functional genomic toolkit for the study of human gut Actinobacteria

Despite the remarkable evolutionary and metabolic diversity found within the human microbiome, the vast majority of mechanistic studies focus on two phyla: the Bacteroidetes and the Proteobacteria. Generalizable tools for studying the other phyla are urgently needed in order to transition microbiome research from a descriptive to a mechanistic discipline. Here, we focus on the Coriobacteriia class within the Actinobacteria phylum, detected in the distal gut of 90% of adult individuals around the world, which have been associated with both chronic and infectious disease, and play a key role in the metabolism of pharmaceutical, dietary, and endogenous compounds. We established, sequenced, and annotated a strain collection spanning 14 genera, 8 decades, and 3 continents, with a focus on Eggerthella lenta. Genome-wide alignments revealed inconsistencies in the taxonomy of the Coriobacteriia for which amendments have been proposed. Re-sequencing of the E. lenta type strain from multiple culture collections and our laboratory stock allowed us to identify errors in the finished genome and to identify point mutations associated with antibiotic resistance. Analysis of 24 E. lenta genomes revealed an \"open\" pan-genome suggesting we still have not fully sampled the genetic and metabolic diversity within this bacterial species. Consistent with the requirement for arginine during in vitro growth, the core E. lenta genome included the arginine dihydrolase pathway. Surprisingly, glycolysis and the citric acid cycle was also conserved in E. lenta despite the lack of evidence for carbohydrate utilization. We identified a species-specific marker gene and validated a multiplexed quantitative PCR assay for simultaneous detection of E. lenta and specific genes of interest from stool samples. Finally, we demonstrated the utility of comparative genomics for linking variable genes to strain-specific phenotypes, including antibiotic resistance and drug metabolism. To facilitate the continued functional genomic analysis of the Coriobacteriia, we have deposited the full collection of strains in DSMZ and have written a general software tool (ElenMatchR) that can be readily applied to novel phenotypic traits of interest. Together, these tools provide a first step towards a molecular understanding of the many neglected but clinically-relevant members of the human gut microbiome.

microbiology↗