Abstract
Escherichia coli O157:H7 is the largest cause of hemolytic uremic syndrome (HUS). Previous studies proposed that HUS risk varies across the E. coli O157:H7 phylogenetic tree (hypervirulent clade 8), but the role of age in the association is unknown. We determined phylogenetic lineage of E. coli O157:H7 isolates from 1160 culture-confirmed E. coli O157:H7 cases reported in Washington State, 2004-2015. Using generalised estimating equations, we tested the association between phylogenetic lineage and HUS. Age was evaluated as an effect modifier. Among 1082 E. coli O157:H7 cases with both phylogenetic lineage and HUS status (HUS n = 76), stratified analysis suggested effect modification by age. Lineages IIa and IIb, relative to Ib, did not appear associated with HUS in children 0-9-years-old. For cases 10-59-years-old, lineages IIa and IIb appeared to confer increased risk of HUS, relative to lineage Ib. The association reversed in ≥60-year-olds. Results were similar for clade 8. Phylogenetic lineage appears to be associated with HUS risk only among those ≥10-years-old. Among children <10, the age group most frequently affected, lineage does not explain progression to HUS. However, lineage frequency varied across age groups, suggesting differences in exposure and/or early disease manifestation.
Original language | English (US) |
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Pages (from-to) | 1550-1555 |
Number of pages | 6 |
Journal | Epidemiology and infection |
Volume | 146 |
Issue number | 12 |
DOIs | |
State | Published - Sep 1 2018 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:Copyright © Cambridge University Press 2018.
Keywords
- Epidemiology
- Escherichia coli (E. coli)
- Shiga toxin-producing E. coli
- phylogenetics