Time filter

Source Type

Ferreira S.,University of Beira Interior | Queiroz J.A.,University of Beira Interior | Oleastro M.,National Institute Of Health Dr Ricardo Jorge | Domingues F.C.,University of Beira Interior
Microbial Pathogenesis | Year: 2014

Even though Arcobacter butzleri has been implicated in some human disease as diarrhoea and bacteraemia, much of its pathogenesis and virulence factors remain unclear.In this work we have compared pathogenic and genotypic properties of six A.butzleri isolates from human and non-human sources. The tested isolates showed to be susceptible to tetracyclines and aminoglycosides, however non-human isolates were all resistant to quinolones. The ability to form biofilms was variable among the tested strains, and all of them showed a weak haemolytic activity. The presence of nine putative virulence genes was determined, with cadF, ciaB, cj1349, mviN, pldA, tlyA being detected in all strains, while irgA (3/6), hecA (5/6), hecB (4/6) were detected only in some strains. High levels of adhesion were observed for A.butzleri on Caco-2 cells, with pre-existing inflammation showing no significant effect on the adherence ability; yet variable levels of invasion were observed. A.butzleri isolates were able to survive intracellularly in Caco-2 cells and to induce a significant up-regulation of interleukin-8 secretion and structural cell rearrangements. These data brings new insights on A.butzleri virulence and highlights its pathogenic potential. © 2014 Elsevier Ltd.

Ferreira S.,University of Beira Interior | Fraqueza M.J.,University of Lisbon | Queiroz J.A.,University of Beira Interior | Domingues F.C.,University of Beira Interior | Oleastro M.,National Institute Of Health Dr Ricardo Jorge
International Journal of Food Microbiology | Year: 2013

The genus Arcobacter is an emerging pathogen associated with several clinical symptoms. This genus is widely distributed and has been isolated from environmental, animal, food and human samples, where poultry is considered the major source. In this study, forty three Arcobacter butzleri strains isolated from poultry and environment of a Portuguese slaughterhouse, were characterized by pulsed field gel electrophoresis (PFGE) and assessed for antimicrobial susceptibility and ability to form biofilms. PFGE patterns obtained using restriction enzymes SmaI and SacII revealed high genetic diversity, with 32 distinct PFGE patterns. Most of A. butzleri isolates presented multiple antimicrobial resistance, exhibiting four different resistance profiles. All 43 isolates were susceptible to gentamicin and 2.3% were resistant to chloramphenicol, in contrast to twenty four (55.8%) that were resistant to ciprofloxacin. Among 36 selected isolates, 26 strains presented biofilm-forming ability, which was dependent on the atmosphere and initial inoculum density.Overall, the results showed that A. butzleri displays a high genetic diversity, and presents resistance to several antibiotics, which together with its biofilm formation ability may represent a potential hazard for foodborne infections and a considerable risk for human health. © 2013 Elsevier B.V.

Nogueira P.J.,National Institute Of Health Dr Ricardo Jorge
Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin | Year: 2010

The experience reported in an earlier Eurosurveillance issue on a fast method to evaluate the impact of the 2003 heatwave on mortality in Portugal, generated a daily mortality surveillance system (VDM) that has been operating ever since jointly with the Portuguese Heat Health Watch Warning System. This work describes the VDM system and how it evolved to become an automated system operating year-round, and shows briefly its potential using mortality data from January 2006 to June 2009 collected by the system itself. The new system has important advantages such as: rapid information acquisition, completeness (the entire population is included), lightness (very little information is exchanged, date of death, age, sex, place of death registration). It allows rapid detection of impacts (within five days) and allows a quick preliminary quantification of impacts that usually took several years to be done. These characteristics make this system a powerful tool for public health action. The VDM system also represents an example of inter-institutional cooperation, bringing together organisations from two different ministries, Health and Justice, aiming at improving knowledge about the mortality in the population.

Torres V.M.,ITQB UNL | Torres V.M.,National Institute Of Health Dr Ricardo Jorge | Posa M.,ITQB UNL | Srdjenovic B.,ITQB UNL | Simplicio A.L.,University of Novi Sad
Colloids and Surfaces B: Biointerfaces | Year: 2011

Fullerene (C60), the third carbon allotrope, is a classical engineered material with the potential application in biomedicine. However, extremely high hydrophobicity of fullerene hampers its direct biomedical evaluation and application. In this work, we investigated the solubilization of fullerene using 9 different solubility enhancers: Tween 20, Tween 60, Tween 80, Triton X-100, PVP, polyoxyethylene (10) lauryl ether, n-dodecyl trimethylammonium chloride, myristyl trimethylammonium bromide and sodium dodecyl sulphate and evaluated its antioxidant activity in biorelevant media. The presence of C60 entrapped in surfactant micelles was confirmed by UV/VIS spectrometry. The efficacy of each modifier was evaluated by chemometric analysis using experimental data for investigating the relationship between solubilization and particle size distribution. Hierarchical clustering and principal component analysis was applied and showed that non-ionic surfactants provide better solubilization efficacy (>85%). A correlation was established (r=0.975) between the degree of solubilization and the surfactant structure. This correlation may be used for prediction of C60 solubilization with non-tested solubility modifiers. Since the main potential biomedical applications of fullerene are based on its free radical quenching ability, we tested the antioxidant potential of fullerene micellar solutions. Lipid peroxidation tests showed that the micellar solutions of fullerene with Triton and polyoxyethylene lauryl ether kept high radical scavenging activity, comparable to that of aqueous suspension of fullerene and BHT. The results of this work provide a platform for further solubilization and testing of pristine fullerene and its hydrophobic derivatives in a biological benign environment. © 2010 Elsevier B.V.

Shivaji T.,U.S. Center for Disease Control and Prevention | Machado J.,National Institute Of Health Dr Ricardo Jorge | Carvalho L.,University of Lisbon | Nunes B.,National Institute Of Health Dr Ricardo Jorge
Eurosurveillance | Year: 2014

An outbreak of Legionnaires’ disease with 334 confirmed cases was identified on 7 November 2014 in Vila Franca de Xira, Portugal and declared controlled by 21 November. Epidemiological, environmental and microbiological analysis identified industrial wet cooling systems to be the probable source of infection. Preliminary results from sequence-based typing of clinical specimens and environmental isolates confirmed this link. A series of meteorological phenomena are likely to have contributed to the scale of this outbreak. © 2014 European Centre for Disease Prevention and Control (ECDC). All rights reserved.

Discover hidden collaborations