title: Fecal diagnostics in combination with serology: best test to establish STEC-HUS.
abstract: In the majority of pediatric patients, the hemolytic-uremic syndrome (HUS) is caused by an infection with Shiga toxin-producing Escherichia coli (STEC), mostly serotype O157. It is important to discriminate between HUS caused by STEC and complement-mediated HUS (atypical HUS) due to differences in treatment and outcome. As STEC and its toxins can only be detected in the patient's stool for a short period of time after disease onset, the infectious agent may go undetected using only fecal diagnostic tests. Serum antibodies to lipopolysaccharide (LPS) of STEC persist for several weeks and may therefore be of added value in the diagnosis of STEC.
  
  
  
  All patients with clinical STEC-HUS who were treated at Radboud University Medical Center between 1990 and 2014 were included in this retrospective single-center study. Clinical and diagnostic microbiological data were collected. Immunoglobulin M (IgM) antibodies against LPS of STEC serotype O157 were detected by a serological assay (ELISA).
  
  
  
  Data from 65 patients weres available for analysis. Fecal diagnostic testing found evidence of an STEC infection in 34/63 patients (54 %). Serological evidence of STEC O157 was obtained in an additional 16 patients. This is an added value of 23 % (p < 0.0001) when the serological antibody assay is used in addition to standard fecal diagnostic tests to confirm the diagnosis STEC-HUS. This added value becomes especially apparent when the tests are performed more than 7 days after the initial manifestation of the gastrointestinal symptoms.
  
  
  
  The serological anti-O157 LPS assay clearly makes a positive contribution when used in combination with standard fecal diagnostic tests to diagnose STEC-HUS and should be incorporated in clinical practice.
authors.affiliation: Department of Pediatric Nephrology, Radboudumc Amalia Children's Hospital, Radboud University Medical Center, P.O. Box 1901, 6500 HB, Nijmegen, Netherlands. Kioa.Wijnsma@radboudumc.nl.
authors.forename: Kioa L
authors.initials: KL
authors.lastname: Wijnsma
authors.affiliation: Department of Pediatric Nephrology, Radboudumc Amalia Children's Hospital, Radboud University Medical Center, P.O. Box 1901, 6500 HB, Nijmegen, Netherlands.
authors.forename: Sheila A M
authors.initials: SA
authors.lastname: van Bommel
authors.affiliation: Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands.
authors.forename: Thea
authors.initials: T
authors.lastname: van der Velden
authors.affiliation: Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands.
authors.forename: Elena
authors.initials: E
authors.lastname: Volokhina
authors.affiliation: Department of Pediatric Nephrology, Radboudumc Amalia Children's Hospital, Radboud University Medical Center, P.O. Box 1901, 6500 HB, Nijmegen, Netherlands.
authors.forename: Michiel F
authors.initials: MF
authors.lastname: Schreuder
authors.affiliation: Department of Pediatric Nephrology, Radboudumc Amalia Children's Hospital, Radboud University Medical Center, P.O. Box 1901, 6500 HB, Nijmegen, Netherlands.|Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands.|Department of Pediatrics, University Hospital Leuven, Leuven, Belgium.
authors.forename: Lambertus P
authors.initials: LP
authors.lastname: van den Heuvel
authors.affiliation: Department of Pediatric Nephrology, Radboudumc Amalia Children's Hospital, Radboud University Medical Center, P.O. Box 1901, 6500 HB, Nijmegen, Netherlands.
authors.forename: Nicole C A J
authors.initials: NC
authors.lastname: van de Kar
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D004927:Escherichia coli Infections / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D019453:Escherichia coli O157 / Q000276:immunology* / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology*; D005260:Female; D006463:Hemolytic-Uremic Syndrome / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D007223:Infant; D008070:Lipopolysaccharides / Q000276:immunology*; D008297:Male; D012189:Retrospective Studies; D058248:Serum Bactericidal Antibody Assay / Q000379:methods; D013997:Time Factors
chemical_list: D000907:Antibodies, Bacterial; D007075:Immunoglobulin M; D008070:Lipopolysaccharides
keywords: Anti-O157 antibodies; Diagnostics; STEC serotype O157; STEC-HUS; Serological LPS antibody detection