Virulence Genes in Isolates of Escherichia coli from Samples of Milk and Feces from Dairy Cattle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pt(II) and Ag(I) complexes with acesulfame: Crystal structure and a study of their antitumoral, antimicrobial and antiviral activities

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

Sub-MICs of Mentha piperita essential oil and menthol inhibits AHL mediated quorum sensing and biofilm of Gram-negative bacteria

Bacterial quorum sensing (QS) is a density dependent communication system that regulates the expression of certain genes including production of virulence factors in many pathogens. Bioactive plant extract/compounds inhibiting QS regulated gene expression may be a potential candidate as antipathogenic drug. In this study anti-QS activity of peppermint (Menthe piperita) oil was first tested using the Chromobacterium violaceum CVO26 biosensor. Further, the findings of the present investigation revealed that peppermint oil (PMO) at sub-Minimum Inhibitory Concentrations (sub-MICs) strongly interfered with acyl homoserine lactone (AHL) regulated virulence factors and biofilm formation in Pseudomonas aeruginosa and Aeromonas hydrophila. The result of molecular docking analysis attributed the QS inhibitory activity exhibited by PMO to menthol. Assessment of ability of menthol to interfere with QS systems of various Gram-negative pathogens comprising diverse AHL molecules revealed that it reduced the AHL dependent production of violacein, virulence factors, and biofilm formation indicating broad-spectrum anti-QS activity. Using two Escherichia colt biosensors, MG4/pKDT17 and pEAL08-2, we also confirmed that menthol inhibited both the las and pqs QS systems. Further, findings of the in vivo studies with menthol on nematode model Caenorhabditis elegans showed significantly enhanced survival of the nematode. Our data identified menthol as a novel broad spectrum QS inhibitor.

Multidrug-resistant Shiga toxin-producing Escherichia coli in dogs with diarrhea

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

Isolation of extraintestinal pathogenic Escherichia coli from diarrheic dogs and their antimicrobial resistance profile

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

Shigatoxigenic Escherichia coli serogroups O157, O111 and O113 in feces, water and milk samples from dairy farms

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

Characterization of Escherichia coli isolated from carcasses of beef cattle during their processing at an abattoir in Brazil

Beef carcass sponge samples collected between March 2003 and August 2005 at an abattoir in Brazil were surveyed for the presence of Shiga toxin-producing Escherichia coli (STEC). Only one carcass among the 80 tested showed a STEC, stx2-encoding gene by PCR amplification. The frequency of carcass contamination by E. coli during processing was tested at three situations, respectively: preevisceration, postevisceration and postprocessing, during the rain and dry seasons. The prevalence of E. coli at the three points was of 30.0%, 70.0%, 27.5% in the rain season and of 22.5%, 55.0%, 17.5% during the dry season, respectively. The E. coli isolates exhibited a high level (45.0%) of multidrug resistance to two or more antimicrobial agents. (c) 2006 Elsevier B.V. All rights reserved.

Inibição do crescimento de Escherichia coli isolada de Queijo Minas Frescal por Lactobacillus acidophilus

Escherichia coli faz parte da microbiota anaeróbica facultativa normal, sendo também considerada um dos maiores patógenos entéricos predominantes no cólon dos animais e homem. Neste trabalho, realizaram-se ensaios in vitro para avaliar o grau de atividade antagonista de cinco cepas de Lactobacillus acidophilus, com capacidade probiótica sobre Escherichia coli BIA 26 (STEC) isolada de queijo Minas Frescal. Para tanto, foi utilizado o teste de inibição através do método de dupla camada em triplicata para avaliar zonas de inibição de crescimento. Todas as cepas de Lactobacillus mostraram-se capazes de inibir a E. coli, com zonas de inibição variando de 12 a 15mm de diâmetro, sendo que a maioria apresentou 14mm de diâmetro, consideradas como fortes halos de inibição.

Phenotypical characterization and adhesin identification in Escherichia coli strains isolated from dogs with urinary tract infections

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Virulence factors of Escherichia coli isolated from diarrheic calves

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Virulence properties and antimicrobial susceptibility of Shiga toxin-producing Escherichia coli strains isolated from healthy cattle from Parana State, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Shiga Toxigenic and Atypical Enteropathogenic Escherichia coli in the Feces and Carcasses of Slaughtered Pigs

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ice as a vehicle for diarrheagenic Escherichia coli

In a recent study of the microbiological quality of commercial ice, 50 Escherichia coli isolates belonging to different serotypes were found. The potential hazard from these isolates was examined by testing their adherence patterns ill HeLa cells and searching for the presence of DNA sequences related to E. coli virulence properties. Twelve potentially diarrheagenic isolates were found and classified as enteroaggregative E. coli (EAEC) based oil their ability to produce aggregative adherence to HeLa cells. The remaining isolates were devoid of the virulence properties searched for. The EAEC isolates belonged to 10 different serotypes, among which O128ab:H35 is often found in diarrheic feces. None of these isolates reacted with a specific EAEC DNA probe or carried any of the known EAEC virulence genes. These data indicate that ice may be all important vehicle for transmission of enteropathogens, especially of the EAEC group. (C) 2003 Elsevier B.V. All rights reserved.

Human colostral phagocytes eliminate enterotoxigenic Escherichia coli opsonized by colostrum supernatant

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