Diagnostic Value of Serological Tests Against Verotoxigenic Escherichia coli in Hemolytic Uremic Syndrome in Children.

Background: Diarrhea-associated hemolytic uremic syndrome (HUS D+) caused by verotoxigenic E. coli strains (VTEC) is a major cause of acute kidney injury in children between 1 and 5 years of age. Because of the short presence of VTEC in the gastrointestinal tract as well as difficulties with the detection of the verotoxigenic strain, identification of HUS etiology might be challenging.

Objectives: The aim of the study was to assess the clinical and diagnostic value of serological tests for specific antibodies against verotoxigenic strains of E. coli in patients with HUS.

Material And Methods: Eight children aged 8 months - 7.1 years (mean 40 ± 29 months) with symptoms of acute kidney injury, hemolytic anemia and thrombocytopenia observed after hemorrhagic diarrhea were included to the study. VTEC presence was detected in a stool culture with subsequent analysis of the ability to produce verotoxin and the presence of VT1 and VT2 as well as intimin and enterohemolysin genes. In addition, the presence of specific IgA, IgM and IgG antibodies against E. coli serogroups O26, O103, O104, O111, O121, O145 and O157 was measured using ELISA.

Results: In 3 subjects, VTEC O26, O157 and O104 serogroups were cultured in the stool and the specific IgA, IgM and IgG antibodies were detected. In 4 subjects, no VTEC strains were cultured, however, high titers of IgA, IgM and IgG antibodies against E. coli O26, O157 and O111 were detected. In a single patient, the negative results of bacteriological and serological analyses excluded VTEC etiology of HUS.

Conclusions: A serological analysis of VTEC can confirm the result of stool culture for verotoxigenic E. coli strains and help to find the cause of HUS in case of negative results of a stool culture.