Table 1. Phenotypic and genotypic characteristics used to identify of diarrheagenic Escherichia coli (DEC) groups in this study.

DEC group	Defining characteristic(s)	Target genes	Multiplex PCR assay
tEPEC	Presence of both intimin (as a marker of the pathogenic island LEE) and the BFP contained in the EAF plasmid	eaeA, bfpA	1
aEPEC	Presence of intimin (as a marker of LEE); absence of the EAF plasmid and Shiga toxins 1 and 2	eaeA	1
ETEC	Presence of thermo labile (LT) or/and thermo stable (ST) toxins	lt, st	1
EIEC	Presence of the invasion-associated locus (IAL) of the invasion plasmid	ial	1
STEC	Presence of Shiga toxin 1 (STX1) and/or 2 (STX2); in addition, some strains also have intimin (as a marker of LEE)	stx1, stx2, eaeA	1
EAEC	Presence of AggR master regulon most genes associated with the aggregative adherence (AA) and EAEC virulence are controlled by this regulon.	aggR	2
DAEC	Presence of surface afimbrial adhesins as AfaE-I and AfaE-III, that are encoded on the Afa/dr/daa operon	afaC	2

ETEC: enterotoxigenic E. coli,

tEPEC: typical enteropathogenic E. coli,

aEPEC: atypical enteropathogenic E. coli,

EAEC: enteroaggregative E. coli,

DAEC: diffusely adherent E. coli.

LEE: locus of enterocyte effacement,

BFP: bundle-forming pilus;

EAF: EPEC adherence factor plasmid, eaeA and afaC: genes encoding for intimin and Afa fimbria usher, respectively.