Format

Send to

Choose Destination
Front Microbiol. 2016 Jan 19;6:1573. doi: 10.3389/fmicb.2015.01573. eCollection 2015.

Phylogenetic Analyses of Shigella and Enteroinvasive Escherichia coli for the Identification of Molecular Epidemiological Markers: Whole-Genome Comparative Analysis Does Not Support Distinct Genera Designation.

Author information

1
Division of Microbiology, Office of Regulatory Science, U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition College Park, MD, USA.
2
Division of Public Health Informatics and Analytics, Office of Analytics and Outreach, U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition College Park, MD, USA.

Abstract

As a leading cause of bacterial dysentery, Shigella represents a significant threat to public health and food safety. Related, but often overlooked, enteroinvasive Escherichia coli (EIEC) can also cause dysentery. Current typing methods have limited ability to identify and differentiate between these pathogens despite the need for rapid and accurate identification of pathogens for clinical treatment and outbreak response. We present a comprehensive phylogeny of Shigella and EIEC using whole genome sequencing of 169 samples, constituting unparalleled strain diversity, and observe a lack of monophyly between Shigella and EIEC and among Shigella taxonomic groups. The evolutionary relationships in the phylogeny are supported by analyses of population structure and hierarchical clustering patterns of translated gene homolog abundance. Lastly, we identified a panel of 404 single nucleotide polymorphism (SNP) markers specific to each phylogenetic cluster for more accurate identification of Shigella and EIEC. Our findings show that Shigella and EIEC are not distinct evolutionary groups within the E. coli genus and, thus, EIEC as a group is not the ancestor to Shigella. The multiple analyses presented provide evidence for reconsidering the taxonomic placement of Shigella. The SNP markers offer more discriminatory power to molecular epidemiological typing methods involving these bacterial pathogens.

KEYWORDS:

Shigella; classification; enteroinvasive E. coli (EIEC); epidemiological markers; phylogeny; whole genome sequencing

Supplemental Content

Full text links

Icon for Frontiers Media SA Icon for PubMed Central
Loading ...
Support Center