Biology subjects

Wende, M.

Publications and source records attributed to Wende, M..

3 recordsLinked to original sources

bioRxiv2025

Metabolites produced by gut bacteria under anoxic conditions drive the suppression of Acinetobacter baumannii

Multidrug-resistant (MDR) bacteria pose a significant global health threat. Among these, Acinetobacter baumannii, particularly carbapenem-resistant A. baumannii, is a leading cause of healthcare-associated infections. Emerging evidence links gut colonization to systemic infections, highlighting opportunities for new control strategies. We demonstrate that A. baumannii can survive under anaerobic conditions ([≤]1%) and shows limited growth under low oxygen conditions ([≥]1%), underscoring its adaptation to niches in the intestine. However, specific carbohydrates, including maltose, provide the gut bacteria Klebsiella oxytoca with a competitive advantage under anoxic conditions, enabling it to actively suppress A. baumannii through its metabolism. Notably, maltose induces this suppressive capacity in other commensals and complex gut microbiomes as well. Force-feeding experiments in Galleria mellonella larvae corroborate that K. oxytoca in combination with maltose significantly reduces A. baumannii recovery in gut environments. These findings suggest that targeted carbohydrate supplementation could enhance probiotic strategies, creating an environment unfavorable to A. baumannii.

microbiology↗

bioRxiv2025

Ablation of polysaccharide breakdown in Bacteroides thetaiotaomicron prevents cross-feeding and growth of Salmonella Typhimurium in the mouse gut

Pathogens invading the intestine compete for nutrients with the resident microbiota. However, there is evidence that commensal members of the gut also provide nutritional resources to enteropathogens and thus promote their outgrowth. In this study, we investigated metabolic cross-feeding mechanisms between the abundant gut commensal Bacteroides thetaiotaomicron and the model enteropathogen Salmonella enterica serovar Typhimurium. We discovered that the processing of various dietary and host-derived glycans by B. thetaiotaomicron liberated building blocks available to Salmonella and identified a range of cross-fed metabolites. Interfering with polysaccharide degradation in B. thetaiotaomicron by genetic manipulation of specific polysaccharide utilization loci (PUL) inhibited pathogenic cross-feeding, both in vitro and in a gnotobiotic mouse model. Our findings highlight the complex metabolic commensal-pathogen interaction in the intestine and propose the disruption of polysaccharide breakdown as a potential microbiota-centric strategy to intervene in intestinal infections.

microbiology↗

bioRxiv2024

Broad diversity of human gut bacteria accessible via a traceable strain deposition system

Numerous bacteria in the human gut microbiome remain unknown and/or have yet to be cultured. While collections of human gut bacteria have been published, few strains have been made publicly available. A major hurdle in making strains publicly available is their deposition to public culture collections. We propose a framework for the bulk-deposition of strains to culture collections, which removes many of the barriers previously identified (www.dsmz.de/bulk-deposit). Using this bulk-deposition system we have created a publicly available collection of human gut isolates. The Human intestinal Bacteria Collection (HiBC) (www.hibc.rwth-aachen.de) contains 340 strains representing 198 species within 29 families and 7 phyla, of which 29 previously unknown species are taxonomically described and named. These included two butyrate-producing species of Faecalibacterium and new dominant species associated with health and inflammatory bowel disease, Ruminococcoides intestinale and Blautia intestinihominis, respectively. Plasmids were prolific within the HiBC isolates, with almost half (46%) of strains containing plasmids, with a maximum of six within a strain. This included a broadly occurring plasmid (pBAC) that exists in three diverse forms across Bacteroidales species. Megaplasmids were identified within two strains, the pMMCAT megaplasmid is globally present within multiple Bacteroidales species. This collection of easily searchable and publicly available gut bacterial isolates will facilitate functional studies of the gut microbiome.

microbiology↗