Encontrados 205 documentos, a visualizar página 1 de 21
Detection of Salmonella enterica serovar Enteritidis using real time PCR, immun...
Almeida, Carina; Cerqueira, L.; Azevedo, N. F.; Vieira, M. J.Several methods for the rapid and specific detection of Salmonella in food samples have been described. Here, we compare 4 of those methods in terms of assay time, procedure complexity, detection limit, sensitivity, specificity and accuracy. Milk, eggs and mayonnaise samples were artificially contaminated with Salmonella enterica serovar Enteritidis cell concentrations ranging from 1 × 10- 2 to 1 × 102 CFU per ...
Fluorescence in situ hybridization method using peptide nucleic acid probes for...
Machado, António; Almeida, Carina; Salgueiro, D. A. L.; Henriques, Ana Filipa; Vaneechoutte, Mario; Haesebrouck, Freddy; Vieira, M. J.; Rodrigues, L. R.Background: Bacterial vaginosis (BV) is a common vaginal infection occurring in women of reproductive age. It is widely accepted that the microbial switch from normal microflora to BV is characterized by a decrease in vaginal colonization by Lactobacillus species together with an increase of Gardnerella vaginalis and other anaerobes. Our goal was to develop and optimize a novel Peptide Nucleic Acid (PNA) Fluore...
Rapid detection of urinary tract infections caused by Proteus spp. using PNA-FISH
Almeida, Carina; Azevedo, N. F.; Bento, Joana C.; Cerca, Nuno; Ramos, H.; Vieira, M. J.; Keevil, C. W.We developed a fluorescence in situ hybridization (FISH) method for the rapid detection of Proteus spp. in urine, using a novel peptide nucleic acid (PNA) probe. Testing on 137 urine samples from patients with urinary tract infections has shown specificity and sensitivity values of 98 % (95 % CI, 93.2–99.7) and 100 % (95 % CI, 80,8–100), respectively, when compared with CHROMagar Orientation medium. Results ind...
Validation of a fluorescence in situ hybridization method using peptide nucleic...
Cerqueira, L.; Fernandes, R. M.; Ferreira, Rui M.; Oleastro, Mónica; Carneiro, Fátima; Brandão, Catarina; Nunes, Pedro Pimentel; Ribeiro, Mário DinisHere, we evaluated a previously established peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) method as a new diagnostic test for Helicobacter pylori clarithromycin resistance detection in paraffin-embedded gastric biopsy specimens. Both a retrospective study and a prospective cohort study were conducted to evaluate the specificity and sensitivity of a PNA-FISH method to determine H. pylori cla...
Detection of Escherichia coli O157 by Peptide Nucleic Acid Fluorescence In Situ...
Almeida, C.; Sousa, J. M.; Rocha, R.; Cerqueira, L.; Fanning, S.; Azevedo, N. F.; Vieira, M. J.Despite the emergence of non-O157 shiga toxin-producing Escherichia coli (STEC) infections, E. coli O157 serotype is still the most commonly identified STEC in world. It causes high morbidity and mortality, and has been responsible for a number of outbreaks in many parts of the world. Various methods have been developed to detect this particular serotype, but standard bacteriological methods remain as the gold ...
Probe4pylori : a new kit for the rapid detection of H. pylori and associated cl...
Cerqueira, L.; Fernandes, R. M.; Ferreira, Rui M.; Oleastro, Mónica; Carneiro, Fátima; Brandão, Catarina; Nunes, Pedro Pimentel; Ribeiro, Mário DinisIn this study an evaluation of Probe4Pylori, a previously established PNA-FISH diagnostic test for H. pylori clarithromycin resistance in paraffin embedded gastric biopsies was performed and compared against culture followed by E-test and PCR. The Probe4Pylori showed very promising results with values of sensitivity (80%) and specificity (approximately 90%) for the patients harboring clarithromycin-resistant H....
Proposal for a method to estimate nutrient shock effects in bacteria
Azevedo, N. F.; Bragança, S. M.; Simões, Lúcia C.; Cerqueira, L.; Almeida, Carina; Keevil, C. W.; Vieira, M. J.Plating methods are still the golden standard in microbiology; however, some studies have shown that these techniques can underestimate the microbial concentrations and diversity. A nutrient shock is one of the mechanisms proposed to explain this phenomenon. In this study, a tentative method to assess nutrient shock effects was tested. Findings To estimate the extent of nutrient shock effects, two strains is...
Characterization of contaminants from a sanitized milk processing plant
Cleto, S.; Matos, Sónia; Kluskens, Leon; Vieira, M. J.Milk processing lines offer a wide variety of microenvironments where a diversity of microorganisms can proliferate. We sampled crevices and junctions where, due to deficient reach by typical sanitizing procedures, bacteria can survive and establish biofilms. The sampling sites were the holding cell, cold storage tank, pasteurizer and storage tank - transfer pump junction. The culturable bacteria that were isol...
Mixing and matching siderophore clusters : structure and biosynthesis of serrat...
Seyedsayamdost, Mohammad R.; Cleto, S.; Carr, Gavin; Vlamakis, Hera; Vieira, M. J.; Kolter, Roberto; Clardy, JonStudying the evolutionary history underlying the remarkable structures and biological activities of natural products has been complicated by not knowing the functions they have evolved to fulfill. Siderophores - soluble, low molecular weight compounds - have an easily understood and measured function: acquiring iron from the environment. Bacteria engage in a fierce competition for acquiring iron, which rewards ...
Comparison of methods to assess biofilm disinfection and recovery by drinking w...
Simões, Lúcia C.; Simões, M.; Vieira, M. J.Drinking water (DW) distribution systems are known to harbour biofilms even in the presence of disinfectants. DW biofilms are constituted by microbial communities adapted to low nutrient concentrations and high chlorine levels. Biofilm formation and resistance to disinfection have been recognized as important factors that contribute to the survival and persistence of microbial contamination in DW. The purpose o...
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