# Genetic and virulence characterization of eae-positive enteropathogenic E. coli (EPEC) clinical isolates from USA patients with diarrhea

> **NIH NIH R21** · LOYOLA UNIVERSITY CHICAGO · 2020 · $191,666

## Abstract

Diarrhea from foodborne pathogens is estimated to cause 47 million illnesses/year in the USA alone. Given the
lack of specificity of symptoms and limitations of microbiological assays, the etiologic agent is often not identified.
Recently, a multiplex PCR assay (FilmArray GI Panel (GIP), BioFire Diagnostics, Salt Lake City, UT) was
approved that screens diarrheal stool samples for 22 enteric pathogens, providing a new perspective on enteric
pathogens in the USA. Particularly surprising is the prevalence of enteropathogenic E. coli (EPEC), ranging from
7-22% of diarrhea samples. EPEC dogma states it is a pathogen of infants in developing countries who are often
malnourished. EPEC is non-invasive; instead, EPEC pathogenesis depends on a type three secretion system
that injects effector proteins into host cells inducing actin pedestals, attaching/effacing lesions, and physiological
changes in intestinal epithelial cells that contribute to diarrhea including alterations in ion transporters and tight
junctions. The presence or absence of the EPEC adherence factor plasmid defines typical EPEC (tEPEC) and
atypical EPEC (aEPEC), respectively. GIP does not distinguish between tEPEC and aEPEC nor does it detect
other virulence genes such as known adhesins or toxins, raising the question of the virulence potential of GIP-
eae-positive strains. Despite the abundance of epidemiological data of EPEC infections worldwide, there is a
lack of knowledge about the characteristics of EPEC infections in industrialized nations. Also, while there is a
wealth of information regarding EPEC T3SS and effectors in prototypical EPEC strains such as E2348/69, there
is a dearth of information linking clinical EPEC strains with functional virulence assays or diarrheal severity.
Although EPEC is detected in some healthy individuals and is often part of a mixed infection, aEPEC occurrence
is on the rise in developing and developed nations and determined to be the causative agent for many outbreaks
in both children and adults. EPEC is also often detected in patients who are immunocompromised due to cancer.
Given the frequency of EPEC identification, the uncertainty of its contribution to diarrhea, and the lack of
detection of other EPEC virulence genes by GIP, it is prudent to characterize these strains to gain insight into
their pathogenicity. Therefore, the overarching goal of this proposal is to determine the virulence properties of
EPEC strains identified by GIP and isolated from humans with diarrhea. The specific aims of this proposal are:
1) Compare EPEC bacterial loads in samples from single versus mixed infections as identified by GIP and
correlate bacterial burden with diarrheal severity; 2) Isolate and characterize genomic virulence propensity of
eae-positive colonies from EPEC-GIP-positive stool samples; 3) Characterize the phenotypic virulence
properties of isolated EPEC strains related to attachment, disruption of tight junctions (TJ), and Cl-/HCO3-
exchanger (DRA) in...

## Key facts

- **NIH application ID:** 9930557
- **Project number:** 5R21AI142515-02
- **Recipient organization:** LOYOLA UNIVERSITY CHICAGO
- **Principal Investigator:** Gail A Hecht
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $191,666
- **Award type:** 5
- **Project period:** 2019-05-16 → 2022-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9930557

## Citation

> US National Institutes of Health, RePORTER application 9930557, Genetic and virulence characterization of eae-positive enteropathogenic E. coli (EPEC) clinical isolates from USA patients with diarrhea (5R21AI142515-02). Retrieved via AI Analytics 2026-06-11 from https://api.ai-analytics.org/grant/nih/9930557. Licensed CC0.

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