Type 2 heat-labile enterotoxin (LT-II)-producing Escherichia coli isolated from ostriches with diarrhea

The culture supernatant of Escherichia coli, isolated from ostriches with diarrhea in Brazil, caused elongation in Vero cell, rounding in Chinese hamster ovary (CHO) cells and a cytoplasmic vacuolation in ostrich embryo fibroblasts (OEF), but it was not cytotoxic for chicken embryo fibroblasts (CEF). These effects were not neutralized by antiserum to cholera toxin. Polymerase chain reaction assays showed that the ostrich E.coli contained the gene encoding (eltII-A), but not those for type 1 heat-labile enterotoxin (eltA), heat-stable enterotoxins (estA, estB), verocytotoxins (stx-I, stx-II), or cytotoxic necrotizing factors (cnf 1, cnf 2). All isolates belonged to serotype O15:H8. The enteropathogenic relevance of LT-II in ostrich diarrhea remains undetermined. (C) 2004 Elsevier B.V. All rights reserved.

O-serogroups, eae gene and EAF plasmid in Escherichia coli isolates from cases of bovine mastitis in Brazil

Mastitis has been recognized for some time as the most costly disease in dairy herds. From March 1997 to August 1998. 2144 samples of bovine mastitic milk were collected, from which 182 Escherichia coli isolates were made, and from which 14 1 isolates had the somatic anti-en (serogroup) determined. Twelve different serogroups were isolated from mastitic milk, and among them were 026, 055, 0111 and 0 119, all of them classic enteropathogenic E. (oh (EPEC) serogroups. These represented 40.0% of the isolates. The 20 of 57 isolates tested had plasmids and in dot blot hybridization, nine isolates were positive for an EaeA probe and an EPEC adherence factor (EAF) probe while two isolates were negative for EaeA probe but positive for the EAF probe, the nine isolates were characterized as attaching and effacing (A/E) E, coli (AEEC) isolates. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Analysis of Escherichia coli isolated from bovine mastitic milk

Rangel P. & Marin J.M. 2009. Analysis of Escherichia coli isolated from bovine mastitic milk. Pesquisa Veterinaria Brasileira 29(5): 363-368. Departamento de Morfologia, Estomatologia e Fisiologia, Faculdade de Odontologia de Ribeirao Preto, Universidade de São Paulo, Avenida do Cafe s/n, Campus USP, Ribeirao Preto, SP 14040-904, Brazil. E-mail: jmmarin@forp.usp.brMastitis has been recognized for some time as the most costly disease in dairy herds. From February to November 2004, 670 samples of bovine mastitic milk from which 231 Escherichia coli strains were isolated, were collected from two Brazilian states. The strains were screened for the presence of Shiga toxin-producing (stx 1 and stx 2) and intimin (eae) genes. Twenty (8.6%) strains were detected by PCR to harbor the Shiga toxin genes (8 the stx 1 gene, 12 the stx 2 gene and none both of them). Two (0.8%) of the Escherichia coli strains studied were eae positive non Shiga toxin-producing. The strains were also examined for resistance to 12 antimicrobial agents. The predominantly observed resistance was to tetracycline (92.2%), streptomycin (90.4%), nalidixic acid (88.3%), amikacin (86.5%) and cephalothin (84.8%). Multidrug resistance was found among 152 isolates (65.8%).

Low intensity laser therapy (LILT) in vivo acts on the neutrophils recruitment and chemokines/cytokines levels in a model of acute pulmonary inflammation induced by aerosol of lipopolysaccharide from Escherichia coli in rat

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Beef Carcass Contamination by Shiga Toxin-Producing Escherichia coli Strains in an Abattoir in Brazil: Characterization and Resistance to Antimicrobial Drugs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Escherichia coli phylogenetic group determination and its application in the identification of the major animal source of fecal contamination

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structure and catalytic mechanism of glucosamine 6-phosphate deaminase from Escherichia coli at 2.1 Å resolution

Background: Glucosamine 6-phosphate deaminase from Escherichia coli is an allosteric hexameric enzyme which catalyzes the reversible conversion of D-glucosamine 6-phosphate into D-fructose 6-phosphate and ammonium ion and is activated by N-acetyl-D-glucosamine 6-phosphate. Mechanistically, it belongs to the group of aldose-ketose isomerases, but its reaction also accomplishes a simultaneous amination/deamination. The determination of the structure of this protein provides fundamental knowledge for understanding its mode of action and the nature of allosteric conformational changes that regulate its function. Results: The crystal structure of glucosamine 6-phosphate deaminase with bound phosphate ions is presented at 2.1 Å resolution together with the refined structures of the enzyme in complexes with its allosteric activator and with a competitive inhibitor. The protein fold can be described as a modified NAD-binding domain. Conclusions: From the similarities between the three presented structures, it is concluded that these represent the enzymatically active R state conformer. A mechanism for the deaminase reaction is proposed. It comprises steps to open the pyranose ring of the substrate and a sequence of general base-catalyzed reactions to bring about isomerization and deamination, with Asp72 playing a key role as a proton exchanger.

Population analysis of susceptibility to propolis in reference strains of Staphylococcus aureus and Escherichia coli

Susceptibility to several ethanolic extracts of propolis (EEP) concentrations was tested with the population analysis technique in reference strains of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 35218). The results of these tests showed that all bacteria were killed by EEP concentrations approximately equal or higher (2.0% v/v - S. aureus; 10.0% v/v - E. coli) than the respective minimal inhibitory concentrations (MIC). Regarding the susceptibility to propolis, there was a homogeneity of data with the respective time kill curves showing a clear bactericidal effect during 6 to 9 h of exposition.