hannanoo

• Beek, Nienke van; Bargheet, Ahmed; Jian, Ching; Noordzij, Hanna Theodora; Ponsero, Alise & Pettersen, Veronika K. [Show all 7 contributors for this article] (2026). Metagenomic survey of pathogen prevalence in the infant gut. Scientific Reports. 16(1). doi: 10.1038/s41598-026-47440-7. Full text in Research Archive
• Nilsen, Jeannette; Sand, Kine M. K.; Al-Khabbaz, Hana J.; Ligtenberg, Lennart Maximilian van; Mester, Simone & Mathiesen, Line [Show all 28 contributors for this article] (2026). Fusion of IgG antibodies to albumin inhibits transport across the placenta. Science immunology. 11(122). doi: 10.1126/sciimmunol.aee5151. Full text in Research Archive Show summary

  Immunoglobulin G (IgG)–based monoclonal antibodies are effective therapies for cancer, autoimmune diseases, and migraine. However, they are actively transported across the placenta by the neonatal Fc receptor (FcRn), limiting their use during pregnancy. Using mouse models and an ex vivo human placental perfusion system, we show that although FcRn binds albumin independently of IgG, albumin is not transported to the fetus in mice or across human placental tissue. Fusion of IgG to albumin markedly reduced transplacental transport in both models while preserving the prolonged plasma half-life conferred by FcRn. Similarly, fragment antigen–binding fragments fused to engineered albumin with enhanced FcRn binding showed minimal fetal exposure. In a mouse model of fetal and neonatal alloimmune thrombocytopenia, albumin fusion of an anti–human platelet antigen IgG reduced fetal antibody transfer and attenuated thrombocytopenia in the offspring. These findings identify albumin as an attractive fusion partner for biologics intended to minimize fetal exposure during pregnancy.

• Pettersen, Veronika Kuchařová; Smidt, Hauke; Ponsero, Alise Jany; Jian, Ching; Riumin, Alona & Kurilshikov, Alexander [Show all 16 contributors for this article] (2026). Off to a good start: current gaps and priorities in early-life microbiome research. FEMS Microbiology Reviews. ISSN 0168-6445. 50. doi: 10.1093/femsre/fuag010. Full text in Research Archive Show summary

  Abstract Early-life microbial exposures are essential for optimal development of human physiology. Yet, understanding of the human microbiome during pregnancy and childhood is still far from being complete. To identify knowledge gaps and establish research priorities, a multidisciplinary expert panel used the Delphi method for consensus development and conducted a literature search on early-life microbiome determinants. Responses from 55 researchers from an online survey were analyzed alongside keyword frequency from 20 501 publications. This approach enabled us to categorize existing evidence and highlight areas requiring investigation. While the main routes for mother-to-child bacterial transmission and their contributions to the newborn microbiome have been studied, many gaps remain. Priority areas include non-bacterial microbes, ecological principles of colonization, environmental and social influences, body sites beyond the gut, and factors affecting the maternal microbiome and its effects on the child’s microbiome. Significance of factors such as hygiene habits, non-antibiotic medications, and pollution remains to be uncovered. Knowledge is also limited on postnatal microbial sharing via household contacts and shared environments (e.g. family members, peers) and the contribution of these pathways to microbiome assembly. We hope this report will guide and inspire future research into the early-life microbiome as a modifiable factor in reducing disease risk.

• Noordzij, Hanna Theodora; Wortel, Meike Tessa; Heintz-Buschart, Anna; Petrikonyte, Patricija; Muinck, Eric de & Trosvik, Pål (2025). Assembly-based analysis of the infant gut microbiome reveals novel ubiquitous plasmids. Plasmid. ISSN 0147-619X. 134, p. 1–15. doi: 10.1016/j.plasmid.2025.102761. Full text in Research Archive Show summary

  Little is known about the role of mobile genetic elements in natural ecosystems such as the infant gut microbiome. Here, we conduct the most comprehensive longitudinal study of the infant plasmidome to date by analyzing monthly fecal samples from 12 infants from birth to one year of age. We employ an assembly-based bioinformatic pipeline for the reconstruction and identification of full-length plasmids, including a novel approach for assigning putative plasmid hosts. We then investigated plasmid content and dynamics in the infant gut microbiome. After assembly and identification, we identified 620 unique circular plasmids in the infant cohort, including a number of novel sequences. Independent assembly of the same plasmids in several samples and infants helped corroborate the authenticity of the plasmids. Among the observed plasmids was the recently described ubiquitous and abundant Bacteroides plasmid pBI143. Overall, the genus Bacteroides had the highest plasmid carriage, while the highest plasmid diversity was observed in Clostridium, including 5 previously unknown widespread plasmids. Lastly, we leveraged the longitudinal nature of our dataset to investigate contemporaneous correlations between temporal variations in plasmid abundances and species dynamics. This enabled us to link co-residing plasmids and tightly linked plasmid-taxon pairs within each infant. These insights into plasmid ecology help us understand determinants driving plasmid distribution in complex microbial communities.

• Seth, Rakoff-Nahoum,; Justine, Debelius,; Mireia, Valles-Colomer,; Noordzij, Hanna Theodora; Maria, Esteban-Torres, & Alexandra, Zhernakova, [Show all 8 contributors for this article] (2025). A reconceptualized framework for human microbiome transmission in early life | Nature Communications. Nature Communications. 16, p. 1–14. doi: 10.1038/s41467-025-61998-2. Full text in Research Archive Show summary

  Human development and physiology are fundamentally linked with the microbiome. This is particularly true during early life, a critical period for microbiome assembly and its impact on the host. Understanding microbial acquisition in early life is thus central to both our basic understanding of the human microbiome and strategies for disease prevention and treatment. Here, we review the historical approaches to categorize microbial transmission originating from the fields of infectious disease epidemiology and evolutionary biology and discuss how this lexicon has influenced our approach to studying the early-life microbiome, often leading to confusion and misinterpretation. We then present a conceptual framework to capture the multifaceted nature of human microbiome acquisition based on four key components: what, where, who, and when. We present ways these parameters may be assigned, with a particular focus on the ‘transmitted strain’ through metagenomics to capture these elements. We end with a discussion of approaches for implementing this framework toward defining each component of microbiome acquisition. Here, the authors provide a critical view of historical approaches to categorize microbial transmission in early life, and present a conceptual framework to capture the multifaceted nature of human microbiome acquisition based on four key components: what, where, who, and when.

• Bargheet, Ahmed; Noordzij, Hanna Theodora; Ponsero, Alise; Jian, Ching; Korpela, Katri & Valles-Colomer, Mireia [Show all 9 contributors for this article] (2025). Dynamics of gut resistome and mobilome in early life: a meta-analysis. EBioMedicine. 114. doi: 10.1016/j.ebiom.2025.105630. Full text in Research Archive Show summary

  <p><i>Background</i> The gut microbiota of infants harbours a higher proportion of antibiotic resistance genes (ARGs) compared to adults, even in infants never exposed to antibiotics. Our study aims to elucidate this phenomenon by analysing how different perinatal factors influence the presence of ARGs, mobile genetic elements (MGEs), and their bacterial hosts in the infant gut. <p><i>Methods</i> We searched MEDLINE and Embase up to April 3rd, 2023, for studies reporting infant cohorts with shotgun metagenomic sequencing of stool samples. The systematic search identified 14 longitudinal infant cohorts from 10 countries across three continents, featuring publicly available sequencing data with corresponding metadata. For subsequent integrative bioinformatic analyses, we used 3981 high-quality metagenomic samples from 1270 infants and 415 mothers. <p><i>Findings</i> We identified distinct trajectories of the resistome and mobilome associated with birth mode, gestational age, antibiotic use, and geographical location. Geographical variation was exemplified by differences between cohorts from Europe, Southern Africa, and Northern America, which showed variation in both diversity and abundance of ARGs. On the other hand, we did not detect a significant impact of breastfeeding on the infants' gut resistome. More than half of detected ARGs co-localised with plasmids in key bacterial hosts, such as <i>Escherichia coli</i> and <i>Enterococcus faecalis</i>. These ARG-associated plasmids were gradually lost during infancy. We also demonstrate that <i>E. coli</i> role as a primary modulator of the infant gut resistome and mobilome is facilitated by its increased abundance and strain diversity compared to adults. <p><i>Interpretation</i> Birth mode, gestational age, antibiotic exposure, and geographical location significantly influence the development of the infant gut resistome and mobilome. A reduction in <i>E. coli</i> relative abundance over time appears as a key factor driving the decrease in both resistome and plasmid relative abundance as infants grow.

• Trosvik, Pål; Noordzij, Hanna Theodora & Muinck, Eric Jacques de (2024). Antibiotic resistance gene dynamics in the commensal infant gut microbiome over the first year of life. Scientific Reports. 14(1). doi: 10.1038/s41598-024-69275-w. Full text in Research Archive Show summary

  Colonization of the infant gut is an important developmental process characterized by high carriage of antimicrobial resistance genes (ARGs) and high abundances of pathobionts. The horizontal transfer of ARGs to pathogenic bacteria represents a major public health concern. However, there is still a paucity of longitudinal studies surveilling ARGs in healthy infant guts at high temporal resolution. Furthermore, we do not yet have a clear view of how temporal variation in ARG carriage relates to the dynamics of specific bacterial populations, as well as community virulence potential. Here, we performed deep shotgun metagenomic sequencing of monthly fecal samples from a cohort of 12 infants, covering the first year of life to interrogate the infant gut microbiome for ARG content. We further relate ARG dynamics to the dynamics of taxa, virulence potential, as well as the potential for ARG mobilization. We identify a core resistome dominated by efflux systems typically associated with Enterobacteriaceae. Overall ARG carriage declined over the first year of life and showed strong contemporaneous correlation with the population dynamics of Proteobacteria. Furthermore, the majority of ARGs could be further mapped to metagenome-assembled genomes (MAGs) classified to this phylum. We were able to assign a large number of ARGs to E. coli by correlating the temporal dynamics of individual genes with species dynamics, and we show that the temporal dynamics of ARGs and virulence factors are highly correlated, suggesting close taxonomic associations between these two gene classes. Finally, we identify ARGs linked with various categories of mobile genetic elements, demonstrating preferential linkage among mobility categories and resistance to different drug classes. While individual variation in ARG carriage is substantial during infancy there is a clear reduction over the first year of life. With few exceptions, ARG abundances closely track the dynamics of pathobionts and community virulence potential. These findings emphasize the potential for development of resistant pathogens in the developing infant gut, and the importance of effective surveillance in order to detect such events.

• Sand, Kine Marita Knudsen; Bern, Malin C.; Nilsen, Jeannette; Noordzij, Hanna Theodora; Sandlie, Inger & Andersen, Jan Terje (2015). Unraveling the interaction between FcRn and albumin: Opportunities for design of albumin-based therapeutics. Frontiers in Immunology. 5:682. doi: 10.3389/fimmu.2014.00682. Full text in Research Archive Show summary

  The neonatal Fc receptor (FcRn) was first found to be responsible for transporting antibodies of the immunoglobulin G (IgG) class from the mother to the fetus or neonate as well as for protecting IgG from intracellular catabolism. However, it has now become apparent that the same receptor also binds albumin and plays a fundamental role in homeostatic regulation of both IgG and albumin, as FcRn is expressed in many different cell types and organs at diverse body sites. Thus, to gain a complete understanding of the biological function of each ligand, and also their distribution in the body, an in-depth characterization of how FcRn binds and regulates the transport of both ligands is necessary. Importantly, such knowledge is also relevant when developing new drugs, as IgG and albumin are increasingly utilized in therapy. This review discusses our current structural and biological understanding of the relationship between FcRn and its ligands, with a particular focus on albumin and design of albumin-based therapeutics.

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• Noordzij, Hanna Theodora (2026). Dispersal of antibiotic resistance genes and mobile genetic elements in the human infant gut. Universitetet i Oslo. Full text in Research Archive Show summary

  The PhD project produced new knowledge about antibiotic resistance and mobile elements in the infant gut microbiota. It was already known that infants have more antibiotic resistance within their gut compared to mothers or other adults. The thesis provides additional evidence of higher abundance of both antibiotic resistance and mobile elements. The bacterial species Escherichia coli was found as a main contributor of these high abundances. Fortunately, Escherichia coli is generally replaced by more favorable species during the maturation of the infant gut microbiota. However, there is a reasonable concern that antibiotic resistance genes are transferred to pathogens during early life. Disease caused by the now resistant pathogen can be difficult to treat. Plasmids, one of the mobile elements, can carry and transfer antibiotic resistance genes between bacteria. To study plasmids within the complex ecosystem of the human infant gut is methodologically challenging. The thesis significantly improves current (bioinformatic) methods for assignment of plasmids to their bacterial host. This will aid future studies to uncover bacterial hosts of resistance plasmids within a complex ecosystem. Moreover, the method gives an indication of plasmid transfer risk when multiple species or genera are associated with the same plasmid.

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