Development and Validation of Shiga Toxin-Producing Escherichia coli Immunodiagnostic Assay

Shiga toxin (Stx)–producing Escherichia coli (STEC) and its subgroup enterohemorrhagic E. coli are important pathogens involved in diarrhea, which may be complicated by hemorrhagic colitis and hemolytic uremic syndrome, the leading cause of acute renal failure in children. Early diagnosis is essential for clinical management, as an antibiotic treatment in STEC infections is not recommended. Previously obtained antibodies against Stx(1) and Stx(2) toxins were employed to evaluate the sensitivity and specificity of the latex Agglutination test (LAT), lateral flow assay (LFA), and capture ELISA (cEIA) for STEC detection. The LAT (mAb Stx(1) plus mAb stx(2)) showed 99% sensitivity and 97% specificity. Individually, Stx(1) antibodies showed 95.5% and 94% sensitivity and a specificity of 97% and 99% in the cEIA and LFA assay, respectively. Stx(2) antibodies showed a sensitivity of 92% in both assays and a specificity of 100% and 98% in the cEIA and LFA assay, respectively. These results allow us to conclude that we have robust tools for the diagnosis of STEC infections.