Geogenomic Segregation and Temporal Trends of Human Pathogenic Escherichia coli O157:H7, Washington, USA, 2005-2014

• Published in: Emerging infectious diseases Vol. 24; no. 1; pp. 32 - 39
• Main Authors: Tarr, Gillian A.M, Shringi, Smriti, Phipps, Amanda I, Besser, Thomas E, Mayer, Jonathan, Oltean, Hanna N, Wakefield, Jon, Tarr, Phillip I, Rabinowitz, Peter
• Format: Journal Article
• Language: English
• Published: U.S. National Center for Infectious Diseases 01.01.2018; Centers for Disease Control and Prevention
• Subjects: Analysis; bacteria; Escherichia coli; Escherichia coli O157; Geogenomic Segregation and Temporal Trends of Human Pathogenic; Health aspects; Infection; Phylogeny; phylogeography; Shiga-toxigenic Escherichia coli; spatial analysis; Washington; Canada; Japan
• ISSN: 1080-6040; 1080-6059
• DOI: 10.3201/eid2401.170851

The often-noted and persistent increased incidence of Escherichia coli O157:H7 infections in rural areas is not well understood. We used a cohort of E. coli O157:H7 cases reported in Washington, USA, during 2005–2014, along with phylogenomic characterization of the infecting isolates, to identify geographic segregation of and temporal trends in specific phylogenetic lineages of E. coli O157:H7. Kernel estimation and generalized additive models demonstrated that pathogen lineages were spatially segregated during the period of analysis and identified a focus of segregation spanning multiple, predominantly rural, counties for each of the main clinical lineages, Ib, IIa, and IIb. These results suggest the existence of local reservoirs from which humans are infected. We also noted a secular increase in the proportion of lineage IIa and IIb isolates. Spatial segregation by phylogenetic lineage offers the potential to identify local reservoirs and intervene to prevent continued transmission.