Molecular typing of antimicrobial-resistant Shiga-toxin-producing Escherichia coli strains (STEC) in Brazil

Antimicrobial resistance patterns and molecular characteristics were determined in thirty-two Shiga-toxin-producing Escherichia coli (STEC) strains previously identified in São Paulo State associated with human infections (n = 21) and in cattle feces (n = 11). the highest resistance rates were identified for tetracycline (100%), streptomycin (78%) and trimethoprim sulfamethoxazole (56%). Eleven STEC strains showed resistance to ampicillin and carried bla(TEM) that was confirmed as bla(TEM-1) in one representative isolate. the class 1 integrase gene (intI1) was detected in seven (22%) strains, and most of them belonged to the O111:H8 serotype. the class 1 integron was located on plasmids in five of the seven STEC strains, and conjugation assays confirmed the plasmid support of those resistant determinants. STEC strains were genetically classified into the B I group, and PFGE analysis showed that most of the strains in each serogroup were grouped into the same cluster (80-97% similarity). the presence of a class 1 integron and bla(TEM-1) genes is described for the first time among STEC isolates in Brazil and clearly represents a public health concern. (C) 2010 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Div Infect Dis, BR-04023062 São Paulo, BrazilJMI Labs, N Liberty, IA USAUniversidade Federal de São Paulo, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Div Infect Dis, BR-04023062 São Paulo, BrazilWeb of Scienc

Humoral immune response to Shiga Toxin 2 (Stx2) among Brazilian urban children with hemolytic uremic syndrome and healthy controls

Background: Shiga toxin (Stx)-producing Escherichia coli (STEC) infection is associated with hemolytic uremic syndrome (HUS), the main cause of acute renal failure in early childhood. Stx is essential in the pathogenesis of HUS, which has been mostly related to Stx2-producing isolates. Very limited data exist on the immune response to STEC in the Brazilian population. in this study, the prevalence of immunoglobulin G (IgG) antibodies to Stx2 was investigated in sera of children diagnosed with HUS and of healthy children in the city of São Paulo, Brazil.Methods: IgG-antibody reactivity to Stx2 was determined by immunoblotting (WB) and enzyme-linked immunosorbent assay (ELISA) in sera from 13 children with HUS aged 8 months to 6 years and 54 healthy urban children aged 5 months to 7 years.Results: A positive immune response to the A and B subunits of Stx2 was observed in 46.1% HUS patients and in 16.6% healthy individuals by WB. All HUS patients and 62.9% healthy children showed IgG antibodies to the Stx2 A subunit. the frequency of antibodies to both subunits or only to the A subunit of Stx2 was significantly higher in HUS patients than controls (p < 0.05). Also, the mean OD value obtained by ELISA was higher in that group. Considering children's age, the frequency of reactivity to either the A subunit or both subunits of Stx2 was considerably higher in HUS children up to three years old compared to controls in the same age range. Moreover, in almost 37% of healthy children, no immune response to Stx2 was detected independently of the child's age.Conclusions: the seroepidemiolgy of anti-Stx2 antibodies was described for the first time in healthy children and children with HUS in Brazil. the percentage of individuals showing antibodies against Stx2 was higher among HUS patients than controls, and in spite of the low number of notified HUS cases, STEC strains are circulating in our settings. in addition, the results obtained also corroborated previous data on the increased sensitivity and specificity of WB compared to toxin-based enzyme immunoassays.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Immunol Parasitol, São Paulo, BrazilInst Butantan, Bacteriol Lab, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pediat, Pediat Intens Care Unit, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Immunol Parasitol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pediat, Pediat Intens Care Unit, São Paulo, BrazilWeb of Scienc

First description of a Shiga toxin-producing Escherichia coli O103:H2 strain isolated from sheep in Brazil

Univ Estadual Londrina, Dept Microbiol, Londrina, BrazilUniversidade Federal de São Paulo, Dept Microbiol Parasitol & Imunol, São Paulo, BrazilInst Butantan, Bacteriol Lab, São Paulo, BrazilUniv Santiago de Compostela, Fac Vet, Dept Microbiol & Parasitol, Lab Referencia E Coli, Lugo, SpainUniversidade Federal de São Paulo, Dept Microbiol Parasitol & Imunol, São Paulo, BrazilWeb of Scienc

Phenotypic and genotypic characteristics of shiga toxin-producing Escherichia coli strains isolated from children in São Paulo, Brazil

The biochemical and serological characteristics, virulence properties, and genetic relatedness of Shiga toxin-producing Escherichia coli (STEC) strains isolated in São Paulo, from April 1989 through March 1990, were determined. This is also the first report on clinic findings of human STEC infections in Brazil. The only three STEC strains identified in that period were lysine decarboxylase negative, belonged to serotype O111ac: non-motile, were Stx1 producers, carried the eae and astA genes, and 2 of them also presented the EHEC-hly sequence. The children carrying STEC were all boys, with less than two years old, and had no previous history of hospitalization. None of them presented blood in stools. Vomiting, cough and coryza were the most common clinical manifestations observed. Although the STEC strains were isolated during summer months, and presented similar phenotypic and genotypic characteristics, carbohydrate fermentation patterns and PFGE analysis suggested that these diarrheal episodes were not caused by a single clone.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de Microbiologia, Imunologia e ParasitologiaUSP Hospital das Clínicas Instituto da CriançaUniversidade Estadual do Rio de JaneiroUniversidade Federal Fluminense Departamento de Microbiologia e ParasitologiaUNIFESP, EPM, Depto. de Microbiologia, Imunologia e ParasitologiaSciEL

Hemolytic Uremic Syndrome in Pediatric Intensive Care Units in São Paulo, Brazil

The hemolytic uremic syndrome (HUS) caused by Shiga toxin-producing Escherichia coli (STEC) is one of the most frequent causes of pediatric acute renal failure. The aim of this study was to report the clinic and microbiologic features associated with 13 post-diarrheal HUS cases identified in pediatric intensive care units in the city of São Paulo, Brazil, from January 2001 to August 2005. Epidemiologic, clinic, and laboratorial information, along with fecal and serum samples, were collected for identifying the genetic sequences of Stx and for studying antibodies directed against LPS O26, O111 and O157. STEC was isolated from three patients, and serotypes O26:H11, O157:H7 and O165:H- were identified. In nine patients, high levels of IgM against LPS O111 (n=2) and O157 (n=7) were detected. Dialysis was required in 76.9% of the patients; arterial hypertension was present in 61.5%, neurological complications were observed in 30.7%, and only one patient died. During a 5–year follow-up period, one patient developed chronic kidney disease. The combined use of microbiologic and serologic techniques provided evidence of STEC infection in 92.3% of the HUS cases studied, and the importance of O157 STEC as agents of HUS in São Paulo has not been previously highlighted