Browsing by Author "Oleastro, M."
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- Arcobacter spp. in food chain – From culture to omicsPublication . Ferreira, S.; Oleastro, M.; Domingues, F.Book description by editor: Food is an essential means for humans and other animals to acquire the necessary elements needed for survival. However, it is also a transport vehicle for foodborne pathogens, which can pose great threats to human health. Use of antibiotics has been enhanced in the human health system; however, selective pressure among bacteria allows the development for antibiotic resistance. Foodborne Pathogens and Antibiotic Resistance bridges technological gaps, focusing on critical aspects of foodborne pathogen detection and mechanisms regulating antibiotic resistance that are relevant to human health and foodborne illnesses This groundbreaking guide: - Introduces the microbial presence on variety of food items for human and animal consumption; - Provides the detection strategies to screen and identify the variety of food pathogens in addition to reviews the literature; - Provides microbial molecular mechanism of food spoilage along with molecular mechanism of microorganisms acquiring antibiotic resistance in food; - Discusses systems biology of food borne pathogens in terms of detection and food spoilage; - Discusses FDA’s regulations and Hazard Analysis and Critical Control Point (HACCP) towards challenges and possibilities of developing global food safety. Foodborne Pathogens and Antibiotic Resistance is an immensely useful resource for graduate students and researchers in the food science, food microbiology, microbiology, and industrial biotechnology.
- Country-wide surveillance of norovirus outbreaks in the Portuguese Army, 2015-2017Publication . Lopes-João, A.; Mesquita, J.R.; de Sousa, R.; Oleastro, M.; Silva, C.; Penha-Gonçalves, C.; Nascimento, M.S.J.INTRODUCTION: Gastrointestinal infections are among the most common foodborne and waterborne diseases in military populations, with direct implications in operational efficiency and force readiness. Through the surveillance system of reportable acute gastrointestinal illness in the Portuguese Army, four norovirus outbreaks were identified between October 2015 and October 2017 in mainland Portugal and the Azores archipelago. The present study documents the epidemiological, clinical and laboratory investigations of these norovirus outbreaks. METHODS: Cases were investigated and epidemiological questionnaires were distributed to all soldiers in each military setting where the outbreaks occurred. Stool samples from soldiers with acute gastroenteritis illness were collected and screened for common enteropathogenic agents. Food and water samples served on the settings were also collected for microbiological investigation. Norovirus-positive samples were further characterised by sequence analysis using a public automated genotyping tool. RESULTS: The four outbreaks affected a total of 99 soldiers among the 618 stationed on base units and in a military exercise. A total of 27 soldiers provided a stool sample, of which 20 were positive for norovirus by real-time PCR. Phylogenetic analysis showed that the noroviruses involved were all genogroup II, namely GII.17, GII.Pe-GII.4 Sydney 2012, GII.P2-GII.2 and GII.P16-GII.2. Of note, 30 soldiers had to receive treatment at the military hospital due to severity of symptoms. CONCLUSION: In this short, two-year surveillance period, a total of four norovirus gastroenteritis outbreaks were detected in the Portuguese Army which caused a considerable morbidity, showing once again the impact of norovirus on Army effectiveness and force readiness.
- First report of a norovirus outbreak associated with the variant Sydney 2012 in PortugalPublication . Mesquita, J.R.; Costa, I.; Oleastro, M.; Conceição-Neto, N.; Nascimento, M.S.Introduction: This study describes the investigation of a gastroenteritis outbreak in a group of students, associated with a dinner reunion in February 2013 in Porto, Portugal. Methodology: An anonymous structured questionnaire was developed and sent to 34 students who attended the dinner reunion. Eighteen students completed the questionnaire and thirteen met the case definition (attack rate of 72%). Stools from two students were screened for norovirus by RT-PCR using primer pairs that target the highly conserved polymerase gene and the capsid gene. Results: Norovirus genotyping confirmed the variant Sydney 2012 as the probable cause of the outbreak. Conclusion: This is the first report of an outbreak associated with the new variant Sydney 2012 in Portugal.
- Genomes of Helicobacter pylori prophagesPublication . Vale, F.F.; Nunes, A.; Oleastro, M.; Gomes, J.P.; Sampaio, D.; Rocha, R.; Vítor, J.; Engstrand, L.; Pascoe, B.; Berthenet, E.; Sheppard, S.; Hitchings, M.D.; Mégraud, F.; Vadivedu, J.; Lehours, P.Nearly 20% of the Helicobacter pylori genomes carry prophages genes. Recently we were able to clearly differentiate four populations of prophages according to geographical origin of host strain. Interestingly we were able to discriminate between Northern Europe and Southern Europe using a phage sequence typing based on 2 prophage genes of H. pylori (integrase and holin) but present in only a minority of strains.
- Genotypic and phenotypic features of Arcobacter butzleri pathogenicityPublication . Ferreira, S.; Queiroz, J.A.; Oleastro, M.; Domingues, F.C.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.
- Helicobacter pullorum cytolethal distending toxin targets vinculin and cortactin and triggers formation of lamellipodia in intestinal epithelial cellsPublication . Varon, C.; Mocan, I.; Mihi, B.; Péré-Védrenne, C.; Aboubacar, A.; Moraté, C.; Oleastro, M.; Doignon, F.; Laharie, D.; Mégraud, F.; Ménard, A.Helicobacter pullorum, a bacterium initially isolated from poultry, has been associated with human digestive disorders. However, the factor responsible for its cytopathogenic effects on epithelial cells has not been formally identified. The cytopathogenic alterations induced by several human and avian H. pullorum strains were investigated on human intestinal epithelial cell lines. Moreover, the effects of the cytolethal distending toxin (CDT) were evaluated first by using a wild-type strain and its corresponding cdtB isogenic mutant and second by delivering the active CdtB subunit of the CDT directly into the cells. All of the H. pullorum strains induced cellular distending phenotype, actin cytoskeleton remodeling, and G2/M cell cycle arrest. These effects were dependent on the CDT, as they were (1) not observed in response to a cdtB isogenic mutant strain and (2) present in cells expressing CdtB. CdtB also induced an atypical delocalization of vinculin from focal adhesions to the perinuclear region, formation of cortical actin-rich large lamellipodia with an upregulation of cortactin, and decreased cellular adherence. In conclusion, the CDT of H. pullorum is responsible for major cytopathogenic effects in vitro, confirming its role as a main virulence factor of this emerging human pathogen.
- Helicobacter pylori infection - recent developments in diagnosisPublication . Lopes, A.I.; Vale, F.F.; Oleastro, M.Considering the recommended indications for Helicobacter pylori (H. pylori) eradication therapy and the broad spectrum of available diagnostic methods, a reliable diagnosis is mandatory both before and after eradication therapy. Only highly accurate tests should be used in clinical practice, and the sensitivity and specificity of an adequate test should exceed 90%. The choice of tests should take into account clinical circumstances, the likelihood ratio of positive and negative tests, the cost-effectiveness of the testing strategy and the availability of the tests. This review concerns some of the most recent developments in diagnostic methods of H. pylori infection, namely the contribution of novel endoscopic evaluation methodologies for the diagnosis of H. pylori infection, such as magnifying endoscopy techniques and chromoendoscopy. In addition, the diagnostic contribution of histology and the urea breath test was explored recently in specific clinical settings and patient groups. Recent studies recommend enhancing the number of biopsy fragments for the rapid urease test. Bacterial culture from the gastric biopsy is the gold standard technique, and is recommended for antibiotic susceptibility test. Serology is used for initial screening and the stool antigen test is particularly used when the urea breath test is not available, while molecular methods have gained attention mostly for detecting antibiotic resistance.
- Helicobacter pylori infection features in a paediatric gastroenterology reference centre in PortugalPublication . Oliveira, L.; Santos, A.; Oleastro, M.; Cabral, J.Aim : To describe H. pylori infecon features in a Portuguese paediatric gastroenterology reference centre over the last five years.
- Helicobacter pylori prevalence, histological and antibiotic resistance patterns among paediatric patients, at a single hospital in Lisbon, during a 5- year periodPublication . Santos, A.; Pereira, L.; Paixão, P.; Braga, A.C.; Oliveira, R.; Catarino, A.; Oleastro, M.Background : Decreasing prevalence of H. pylori infection has been reported worldwide, in parallel with the improvement in sociodemographic conditions. In contrast, in Portugal, there is still a high prevalence of infection, including in pediatric population, and of gastric carcinoma. Aim : This study aims to evaluate H. pylori prevalence, histological and antibiotic resistance patterns in symptomatic Portuguese children/adolescents attending a hospital in Lisbon.
- Helicobacter pylori strains from ulcer and non-ulcer differ in binding ability to mucinsPublication . Quintana-Hayashi, M.P.; Rocha, R.; Roxo-Rosa, M.; Oleastro, M.; Linden, S.K.Background : Adhesion to mucins within the mucus layer and to membrane bound mucins present on the surface epithelial cells is a key step in the interacon of H. pylori and its host. Aim : To invesgate the level and mechanisms of binding of non- ulcer dyspepsia (NUD) strains versus pepc ulcer disease (PUD) strains to human gastric mucins.
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