biostudies-literatureLitvak YCalifornia Agricultural Experimental StationNIAID NIH HHSPublic Health ServiceUSDA128-139.e5https://www.ebi.ac.uk/biostudies/studies/S-EPMC12036633biostudies-literatureUnknown25(1)Neonates are highly susceptible to infection with enteric pathogens, but the underlying mechanisms are not resolved. We show that neonatal chick colonization with Salmonella enterica serovar Enteritidis requires a virulence-factor-dependent increase in epithelial oxygenation, which drives pathogen expansion by aerobic respiration. Co-infection experiments with an Escherichia coli strain carrying an oxygen-sensitive reporter suggest that S. Enteritidis competes with commensal Enterobacteriaceae for oxygen. A combination of Enterobacteriaceae and spore-forming bacteria, but not colonization with either community alone, confers colonization resistance against S. Enteritidis in neonatal chicks, phenocopying germ-free mice associated with adult chicken microbiota. Combining spore-forming bacteria with a probiotic E. coli isolate protects germ-free mice from pathogen colonization, but the protection is lost when the ability to respire oxygen under micro-aerophilic conditions is genetically ablated in E. coli. These results suggest that commensal Enterobacteriaceae contribute to colonization resistance by competing with S. Enteritidis for oxygen, a resource critical for pathogen expansion.Cell host & microbeCommensal Enterobacteriaceae Protect against Salmonella Colonization through Oxygen Competition.PMC12036633R37 AI044170AI112445AI044170R01 AI112445R56 AI112949AI060555R01 AI044170T32 AI060555AI112949R01 AI096528AI096528R01 AI112949Mon KKZTsolis RMLitvak YByndloss MXZhu YByndloss AJAlcantara MABronner DNTiffany CRNguyen HFaber FVelazquez EMKutter LWalker GTBaumler AJLiou MZhou HChanthavixay GfalseCommensal Enterobacteriaceae Protect against Salmonella Colonization through Oxygen Competition.Neonates are highly susceptible to infection with enteric pathogens, but the underlying mechanisms are not resolved. We show that neonatal chick colonization with Salmonella enterica serovar Enteritidis requires a virulence-factor-dependent increase in epithelial oxygenation, which drives pathogen expansion by aerobic respiration. Co-infection experiments with an Escherichia coli strain carrying an oxygen-sensitive reporter suggest that S. Enteritidis competes with commensal Enterobacteriaceae for oxygen. A combination of Enterobacteriaceae and spore-forming bacteria, but not colonization with either community alone, confers colonization resistance against S. Enteritidis in neonatal chicks, phenocopying germ-free mice associated with adult chicken microbiota. Combining spore-forming bacteria with a probiotic E. coli isolate protects germ-free mice from pathogen colonization, but the protection is lost when the ability to respire oxygen under micro-aerophilic conditions is genetically ablated in E. coli. These results suggest that commensal Enterobacteriaceae contribute to colonization resistance by competing with S. Enteritidis for oxygen, a resource critical for pathogen expansion.2019-01-01T00:00:00Z2019 Jan2026-06-01T07:50:53.634Z2025-06-27T03:05:14.32ZS-EPMC120366333062991310.1016/j.chom.2018.12.003