Surface architecture of the bacterial envelope determines phage adsorption route in pathogenic Escherichia coli O157:H7
- 1Environmental Genomics & Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
Abstract
The outermost surface layers of Gram-negative bacteria determine phage access to terminal receptors, yet their genetic basis has been mapped almost exclusively in laboratory strains that lack them. Here we apply genome-wide RB-TnSeq fitness profiling to four Escherichia coli O157:H7 strains from distinct phylogenetic clades sharing the O157 O-antigen, using 38 phages with terminal receptors previously mapped in E. coli K-12 strain. RB-TnSeq fitness landscapes across all four pathogenic backgrounds were mostly similar, and dominated by surface-associated loci, including the gfc-etk group 4 capsule operon, O-antigen biosynthesis genes, LPS core assembly genes and outer membrane proteins. Disruption of gfc-etk abolished infection in 11 genetically diverse myoviruses, establishing the O-antigen capsule as a widespread required primary recognition substrate. O-antigen loci generated two classes of fitness score patterns. For 10 phages, disruption increased infectivity, indicating it is a barrier to receptor access; for 3 others, disruption abolished infectivity, demonstrating it can also be a primary recognition substrate. Outer membrane protein receptor identity was conserved across laboratory and pathogenic backgrounds, with the same proteins recognized in both K-12 and O157:H7, while glycan layer state determines whether these receptors are reached. These results demonstrate that outer surface glycan layers can act as primary and optional recognition substrates for phage infection, or as physical barriers preventing terminal receptor access. Extending the ability to probe phage-targeted receptors beyond outer membrane proteins provides a framework for incorporating glycan layer state into predictive models of phage-host interactions.
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BibTeX
@misc{riveralopez2026surface,
title = {{Surface architecture of the bacterial envelope determines phage adsorption route in pathogenic Escherichia coli O157:H7}},
author = {E. O. Rivera-Lopez and L. Moriniere and A. Kazakov and D. Piya and M. Pena and B. Weinberg and J. Feng and A. J. C. Noonan and D. W. Lacher and A. Deutschbauer and A. P. Arkin and V. K. Mutalik and E. G. Dudley},
howpublished = {bioRxiv},
year = {2026},
month = jul,
doi = {10.64898/2026.07.23.740414},
url = {https://www.biorxiv.org/content/10.64898/2026.07.23.740414v2},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Surface architecture of the bacterial envelope determines phage adsorption route in pathogenic Escherichia coli O157:H7
AU - E. O. Rivera-Lopez
AU - L. Moriniere
AU - A. Kazakov
AU - D. Piya
AU - M. Pena
AU - B. Weinberg
AU - J. Feng
AU - A. J. C. Noonan
AU - D. W. Lacher
AU - A. Deutschbauer
AU - A. P. Arkin
AU - V. K. Mutalik
AU - E. G. Dudley
PY - 2026
DA - 2026/07/23
PB - bioRxiv
DO - 10.64898/2026.07.23.740414
UR - https://www.biorxiv.org/content/10.64898/2026.07.23.740414v2
AB - The outermost surface layers of Gram-negative bacteria determine phage access to terminal receptors, yet their genetic basis has been mapped almost exclusively in laboratory strains that lack them. Here we apply genome-wide RB-TnSeq fitness profiling to four Escherichia coli O157:H7 strains from distinct phylogenetic clades sharing the O157 O-antigen, using 38 phages with terminal receptors previously mapped in E. coli K-12 strain. RB-TnSeq fitness landscapes across all four pathogenic backgrounds were mostly similar, and dominated by surface-associated loci, including the gfc-etk group 4 capsule operon, O-antigen biosynthesis genes, LPS core assembly genes and outer membrane proteins. Disruption of gfc-etk abolished infection in 11 genetically diverse myoviruses, establishing the O-antigen capsule as a widespread required primary recognition substrate. O-antigen loci generated two classes of fitness score patterns. For 10 phages, disruption increased infectivity, indicating it is a barrier to receptor access; for 3 others, disruption abolished infectivity, demonstrating it can also be a primary recognition substrate. Outer membrane protein receptor identity was conserved across laboratory and pathogenic backgrounds, with the same proteins recognized in both K-12 and O157:H7, while glycan layer state determines whether these receptors are reached. These results demonstrate that outer surface glycan layers can act as primary and optional recognition substrates for phage infection, or as physical barriers preventing terminal receptor access. Extending the ability to probe phage-targeted receptors beyond outer membrane proteins provides a framework for incorporating glycan layer state into predictive models of phage-host interactions.
ER -