Providencia alcalifaciens strains translocate from the gastrointestinal tract and are resistant to lytic activity of serum complement

The ability of Providencia alcalifaciens strains, isolated from patients with diarrhoeal disease, to translocate from the gastrointestinal tract and their resistance to serum complement lytic activity were investigated and compared with previously characterized differential invasive capabilities in HeLa cells. Translocation ability to several extraintestinal sites and resistance to lysis by human serum complement were observed in both highly invasive and non-invasive strains. These characteristics have not been previously described in P. alcalifaciens and their potential role in causing disseminated infections should therefore be considered.Universidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, SP, BrazilFed Univ Para, Dept Patol, BR-66059 Belem, Para, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Tecn Operatoria, BR-04023062 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Immunol & Parasitol, BR-04023062 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Tecn Operatoria, BR-04023062 São Paulo, SP, BrazilWeb of Scienc

Characterization of enterotoxigenic Escherichia coli by random amplification of polymorphic DNA

Two enterotoxigenic Escherichia coli (ETEC) strains (H10407 and 4011-1) were characterized by random amplification of polymorphic DNA (RAPD) profiles using 10-mer oligonucleotides with diverse GC content, All tested primers yielded arrays of amplified DNA products ranging in size from 200 to 3000 bp. the effects of annealing temperature, template concentration and GC content of the primers were evaluated and an optimal reaction procedure was established. Application of the RAPD analysis to ten ETEC strains belonging to five different serotypes showed that strains of the same serotype shared identical or almost identical band profiles, suggesting a similar genetic composition. the use of RAPD profiles as a tool in epidemiological analysis of ETEC is discussed.UNIV FED RIO de JANEIRO,CCS,INST BIOFIS CARLOS CHAGAS FILHO,BR-21941590 RIO JANEIRO,BRAZILESCOLA PAULISTA MED,DISCIPLINA MICROBIOL & IMUNOL,BR-04023062 São Paulo,BRAZILESCOLA PAULISTA MED,DISCIPLINA MICROBIOL & IMUNOL,BR-04023062 São Paulo,BRAZILWeb of Scienc

High occurrence of Shiga toxin-producing Escherichia coli (STEC) in healthy cattle in Rio de janeiro State, Brazil

In order to evaluate the prevalence of Shiga toxin-producing Escherichia coli (STEC) strains, 197 fecal samples of healthy cattle from 10 dairy farms, four beef farms and one slaughterhouse at Rio de Janeiro State, Brazil, were examined for Shiga toxin (Stx) gene sequences by polymerase chain reaction (PCR). for presumptive isolation of O157:H7 E. coli, the Cefixime-potassium tellurite-sorbitol MacConkey Agar (CT-SMAC) was used. A high occurrence (71%) of Stx was detected, and was more frequently found among dairy cattle (82% vs. 53% in beef cattle), in which no differences were observed regarding the age of the animals. Dot blot hybridization with stx1 and stx2 probes revealed that the predominant STEC type was one that had the genes for both stx1 and stx2 in dairy cattle and one that had only the stx1 gene for beef cattle. Three (1.5%) O157:H7 E. coli strains were isolated from one beef and two dairy animals by the use of CT-SMAC. To our knowledge, this is the first report of O157:H7 isolation in Brazil. A PCR-based STEC detection protocol led to the isolation of STEC in 12 of 16 randomly selected PCR-positive stool samples. A total of 15 STEC strains belonging to 11 serotypes were isolated, and most of them (60%) had both stx1 and stx2 gene sequences. Cytotoxicity assays with HeLa and Vero cells revealed that all strains except two of serotype O157:H7 expressed Stx. the data point to the high prevalence of STEC in our environment and suggest the need for good control strategies for the prevention of contamination of animal products. (C) 1999 Elsevier Science B.V. All rights reserved.Univ Fed Fluminense, Dept Microbiol & Parasitol, BR-24210130 Niteroi, RJ, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilUniv Estado Rio de Janeiro, Disciplina Microbiol & Imunol, Rio de Janeiro, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilWeb of Scienc

Virulence properties of Escherichia coli strains belonging to enteropathogenic (EPEC) serogroups isolated from calves with diarrhea

Nineteen Escherichia coli strains belonging to enteropathogenic (EPEC) serogroups were isolated from calves with diarrhea in Parana State, Brazil, and studied for virulence markers associated with EPEC or enterohemorrhagic E. coli (EHEC). the 19 isolates belonged to 12 serotypes with isolates of O26:H11, O119:H25 and O114:H- being the most prevalent. Localized adherence (LA) was demonstrated for 37% of the isolates, consisting of all four O26:H11, both O114:H- and one O114:H40 isolates. All the LA strains were positive in the fluorescent-actin staining (FAS) test and possessed attaching-effacing E. coli (eae) sequences, but only O114 strains hybridized with the EPEC adherence factor (EAF) probe. None of the strains produced Shiga-like toxins (Verotoxin). Only the O26:H11 strains hybridized with the EHEC plasmid specific (CVD419) probe and were enterohemolytic, properties associated with EHEC strains. This investigation demonstrates that among the bovine strains isolated only those of serogroup O114 behaved as typical EPEC.Universidade Federal de São Paulo,ESCOLA PAULISTA MED,DISCIPLINA MICROBIOL,BR-04023062 São Paulo,BRAZILUniversidade Federal de São Paulo,ESCOLA PAULISTA MED,DISCIPLINA MICROBIOL,BR-04023062 São Paulo,BRAZILWeb of Scienc