ABSTRACT: Shiga toxin-producing Escherichia coli (STEC) is a significant public health concern, with plasmids playing a key role in its pathogenicity. This study investigates the relationship between plasmid types, virulence genes, and host specificity in 96 STEC strains isolated from cattle, sheep, goats, and pigeons in Iran. We examined the distribution of plasmid-encoded virulence genes, including astA, cma, cba, rhsA1, rhsA2, rhsC, stcE, katP, toxB, espP, subAB, ihaG, LAA iha, saa, etpD, cif, and epeA, along with ehxA subtypes and plasmid replicon types using PCR and RFLP analysis. The most frequently detected virulence factors, rhsC and ihaG, were associated with ehxA subtype A and IncFIB/IncK/B plasmids. Pigeon-derived isolates had a unique virulence profile, including cif but lacking ehxA, su
