Jpn.J.Infect.Dis., 52, 33-37, 1999

Original Article

A Clinical and Bacteriological Study of Children Suffering from Haemolytic Uraemic Syndrome in Tucman, Argentina

Susana Miceli3, Maria Angela Jure1,2, Olga A de Saab1, Marta C de Castillo1,*, Susana Rojas3, Aida P de Ruiz Holgado1,2 and Olga M de Nader1

1Instituto de Microbiologia, Facultad de Bioquimica, Quimica y Farmacia,Universidad Nacional de Tucuman (UNT), Ayacucho 471, (4000) S.M. de Tucuman, Argentina, 2CERELA (Centro de Referencias para Lactobacilos) (Lactobacillus Reference Centre), Chacabuco 145, (4000) S.M. de Tucuman, Argentina and 3Servicio de Nefrologia, Hospital del Nino Jesus (Nephrology Department, Children's Hospital), Tucuman, Argentina

(Received October 6, 1998. Accepted March 23, 1999)

SUMMARY: Haemolytic uraemic syndrome (HUS) is a disease with serious consequences for children, such as terminal chronic renal failure. During the last few years there have been numerous studies undertaken to determine whether there is a relationship between this disease and the presence of Shiga toxin-producing bacteria. Escherichia coli (E. coli) O157:H7 is one of the most frequent etiologic agents of HUS. It acts through cytotoxins called Shiga toxin 1 (Stx1) and/or Shiga toxin 2 (Stx2) and carries a 90-Kb plasmid codified for an adhesion fimbria which is part of its pathogenicity. The objectives of this study were to: 1) confirm whether there exists a relationship between severity and clinical presentation of HUS; 2) prove the existence of Stx1 and/or Stx2 in the faeces of HUS patients; and 3) detect the presence of Stx1- and/or Stx2-producing E. coli. Our results did not show any difference in the average age, sex or clinical behavior between children with diarrhea positive (D+) HUS and diarrhea negative (D-) HUS. Male patients were predominant, as was incidence during summer, considering all cases. Nor could we find any relationship between severity and HUS type. E. coli O157:H7 was isolated in 40% of the patients with (D+) HUS and in 50% of patients with (D-) HUS. Another serotype, O55:K59, was also isolated (7%). Stx1 and/or Stx2 were found in all HUS cases. The following virulence factors of E. coli strains isolated from 12 patients were found: Adhesion fimbria (100%), Stx1 (16%), Stx2 (32%), and Stx1 + Stx2 (50%). None of these factors was found in control patients. Sixty-three percent of the HUS cases showed seroconversion for lipopolysaccharides of E. coli O157. We drew the following conclusions: 1) there is no significant relationship between seriousness of HUS and type of disease; 2) an association exists between HUS and the production of Stx1 and Stx2; 3) the incidence of E. coli O157:H7 was high in Tucuman, Argentina; and 4) Stx2 alone or in association with Stx1 was the predominant toxin.

*Corresponding author: Address: Avenida J.B. Justo 1192, (4000) S.M. de Tucuman, Argentina, Fax: +54-381-424 8169

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