title: Persistent bloody diarrhoea without fever associated with diffusely adherent Escherichia coli in a young child.
abstract: Diffusely adherent Escherichia coli (DAEC) is thought to cause diarrhoea in children, and so too are other diarrhoeagenic E. coli (DEC); however, the evidence base is inconclusive. DEC pathotypes are differentiated on the basis of their pathogenic features, and thus cannot be quickly identified on selective culture media. Molecular techniques, not readily available in most clinical laboratories, are required to differentiate DEC strains from non-pathogenic E. coli in the stool flora. We report a case of persistent bloody diarrhoea, without fever, in a previously healthy 21-month infant from whom we isolated five DAEC strains. The child's stools movements were loose, with gross blood and mucus; fresh mount analysis revealed numerous faecal leukocytes and erythrocytes. Response to antimicrobial treatment with trimethoprim-sulfamethoxazole was poor despite susceptibility in vitro. Although the patient improved with azithromycin, blood was present in the patient's stools for over 30 days. The severe diarrhoea in this patient might be explained by the fact that these DAEC isolates harboured a siderophore receptor, which allows the bacteria to use iron derived from haem compounds that promote its multiplication. The isolates also induced in vitro secretion of several immunomodulatory cytokines that may account for the patient's loose stools and faecal leukocytes. DAEC may play a greater role than suspected in afebrile children with bloody diarrhoea.
authors.affiliation: Department of Molecular Biomedicine, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, Mexico.
authors.forename: Sandra
authors.initials: S
authors.lastname: Patzi-Vargas
authors.affiliation: Infectious Diseases Research Unit, Hospital Regional de Alta Especialidad de La Península de Yucatán, Mérida, Yucatán, Mexico.|Microbiology Research Laboratory and Paediatric Emergency Department, Hospital General O'Horan, Mérida, Yucatán, Mexico.
authors.forename: Mussaret
authors.initials: M
authors.lastname: Zaidi
authors.affiliation: Department of Molecular Biomedicine, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, Mexico.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Bernal-Reynaga
authors.affiliation: Microbiology Research Laboratory and Paediatric Emergency Department, Hospital General O'Horan, Mérida, Yucatán, Mexico.
authors.forename: Magda
authors.initials: M
authors.lastname: León-Cen
authors.affiliation: Microbiology Research Laboratory and Paediatric Emergency Department, Hospital General O'Horan, Mérida, Yucatán, Mexico.
authors.forename: Alba
authors.initials: A
authors.lastname: Michel
authors.affiliation: Department of Molecular Biomedicine, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, Mexico.
authors.forename: Teresa
authors.initials: T
authors.lastname: Estrada-Garcia
mesh_terms: D003967:Diarrhea / Q000175:diagnosis* / Q000382:microbiology*; D004926:Escherichia coli / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000382:microbiology; D005334:Fever / Q000175:diagnosis* / Q000382:microbiology*; D006801:Humans; D007223:Infant; D008297:Male