1,761 research outputs found
Tuning the microstructure of flash sintered BZT-BCT ceramics to obtain enhanced and singular properties
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Serotypes, virulence genes, and PFGE patterns of enteropathogenic Escherichia coli isolated from Cuban pigs with diarrhea
Thirty-six enteropathogenic Escherichia coli strains isolated from Cuban pigs with diarrhea were serotyped and screened by PCR for the presence of virulence genes. The 36 isolates belonged to 11 O serogroups and 14 O:H serotypes, with 53% of the isolates belonging to only two serotypes: O141:Hâ (13 isolates) and O157:H19 (6 isolates). Genes coding for STb, STa, VT2e, and LT toxins were identified in 69, 61, 53, and 6% of the isolates, respectively. The most prevalent fimbrial adhesin was F18, detected in 22 (61%) isolates. The gene encoding F6 (P987) colonization factor was identified in three (8%) isolates. None of the 36 isolates assayed contained genes encoding F4 (K88), F5 (K99), or F41. The seropathotype O141:Hâ:STa/STb/VT2e/F18 (13 isolates) was the most frequently detected, followed by O157:H19:VT2e/F18 (5 isolates). A genetic diversity study, carried out by pulsed-field gel electrophoresis (PFGE) of 24 representative isolates, revealed 21 distinct restriction patterns clustered in 18 groups (IâXVIII). Isolates of the same serotype were placed together in a dendrogram, but isolates of serotype O157:H19 showed a high degree of polymorphism. The results of this study demonstrate the presence in Cuba of different clusters among one of the most prevalent serotypes isolated from pigs with diarrhea. Further experiments are needed to determine whether some of these clusters have appeared recently; if so, their evolution, as well as their possible association with pathogenicity in farms should be studied. [Int Microbiol 2006; 9(1):53-60
A sequence stratigraphic based geological model for constraining hydrogeological modeling in the urbanized area of the Quaternary BesĂČs delta (NW Mediterranean coast, Spain)
The Quaternary BesĂČs delta is located on the Mediterranean coast in NE Spain. The BesĂČs Delta Complex includes 3 aquifers constituted by 3 sandy and gravelly bodies, separated by lutitic units. These aquifers supply water for domestic and industrial use in this area. Management of groundwater has been problematic in the BesĂČs delta since the 1960s, and continues to pose major problems for subsurface engineering works in this highly urbanized region. This study seeks to demonstrate the advantages of detailed geological characterization and modeling for designing and constructing a hydrogeological model. Available information of the subsurface was compiled, integrated and homogenized in a geospatial database. The interpretation of these data enabled us to delimit geological units by means of a sequence stratigraphic subdivision. A three-dimensional facies belt-based model of the BesĂČs delta was built on the basis of this geological characterization. This model was used to constrain the distribution of hydraulic parameters and thus to obtain a consistent hydrogeological model of the delta, which was calibrated by data of water management and production over the last hundred years. The resulting hydrogeological model yielded new insights into water front displacements in the aquifer during the time-span considered, improving predictions in an attempt to optimize aquifer management
Serotypes, virulence genes, and PFGE profiles of Escherichia coli isolated from pigs with postweaning diarrhoea in Slovakia
BACKGROUND: Postweaning diarrhoea (PWD) in pigs is usually the main infectious problem of large-scale farms and is responsible for significant losses worldwide. The disease is caused mainly by enterotoxigenic E. coli (ETEC) and Shiga-toxin producing E. coli (STEC). In this study a total of 101 E. coli isolated from pigs with PWD in Slovakia were characterized using phenotypic and genotypic methods. RESULTS: These 101 isolates belonged to 40 O:H serotypes. However, 57% of the isolates belonged to only six serotypes (O9:H51, O147:H-, O149:H10, O163:H-, ONT:H-, and ONT:H4), including two new serotypes (O163:H- and ONT:H4) not previously found among porcine ETEC and STEC isolated in other countries. Genes for EAST1, STb, STa, LT and Stx2e toxins were identified in 64%, 46%, 26%, 20%, and 5% of isolates, respectively. PCR showed that 35% of isolates carried genes for F18 colonization factor, and further analyzed by restriction endonuclease revealed that all of them were F18ac. Genes for F4 (K88), F6 (P987), F17, F5 (K99), F41, and intimin (eae gene) adhesins were detected in 19 %, 5%, 3%, 0.9%, 0.9%, and 0.9% of the isolates, respectively. The study of genetic diversity, carried out by PFGE of 46 representative ETEC and STEC isolates, revealed 36 distinct restriction profiles clustered in eight groups. Isolates of the same serotype were placed together in the dendrogram, but high degree of polymorphism among certain serotypes was detected. CONCLUSION: Seropathotype O149:H10 LT/STb/EAST1/F4 (14 isolates) was the most commonly detected followed by O163:H- EAST1/F18 (six isolates), and ONT:H4 STa/STb/Stx2e/F18 (five isolates). Interestingly, this study shows that two new serotypes (O163:H- and ONT:H4) have emerged as pig pathogens in Slovakia. Furthermore, our results show that there is a high genetic variation mainly among ETEC of O149:H10 serotype
Microstructure and Defect Formation in BaTiO3 Ceramics Obtained by Flash Sintering of Micro and Nanopowders
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Fecal carriage of Escherichia coli O157:H7 and carcass contamination in cattle at slaughter in northern Italy
Feedlot cattle slaughtered at a large abattoir in northern Italy during 2002 were examined for intestinal carriage and carcass contamination with Escherichia coli O157:H7. Carcass samples were taken following the excision method described in the Decision 471/2001/EC, and fecal material was taken from the colon of the calves after evisceration. Bacteria were isolated and identified according to the MFLP-80 and MFLP-90 procedures (Food Directorateâs Health Canadaâs). Eighty-eight non-sorbitol-fermenting E. coli O157:H7 isolates were obtained from 12 of the 45 calves examined. In particular, E. coli O157:H7 isolates were found in 11 (24%) fecal and five (11%) carcass samples. PCR analysis showed that all 11
fecal samples and five carcass samples carried eae-Îł1-positive E. coli O157:H7 isolates. In addition, genes encoding Shigatoxins were detected in O157:H7 isolates from nine and two of those 11 fecal and five carcasses, respectively. A representative group of 32 E. coli O157:H7 isolates was analyzed by phage typing and DNA macrorestriction fragment analysis (PFGE). Five phage types (PT8, PT32v, PT32, PT54, and PT not typable) and seven (IâVII) distinct restriction patterns of similarity
> 85% were detected. Up to three different O157:H7 strains in an individual fecal sample and up to four from the same animal could be isolated. These findings provide evidence of the epidemiological importance of subtyping more than one isolate from the same sample. Phage typing together with PFGE proved to be very useful tools to detect cross-contamination among carcasses and should therefore be included in HACCP programs at abattoirs. The results showed that the same PFGE-phage type E. coli O157:H7 profile was detected in the fecal and carcass samples from an animal, and also in two more carcasses corresponding to two animals slaughtered the same day. [Int Microbiol 2007; 10(2):109-116
Extraintestinal pathogenic Escherichia coli O1:K1:H7/NM from human and avian origin: detection of clonal groups B2 ST95 and D ST59 with different host distribution
<p>Abstract</p> <p>Background</p> <p>Extraintestinal pathogenic <it>Escherichia coli </it>(ExPEC) strains of serotype O1:K1:H7/NM are frequently implicated in neonatal meningitis, urinary tract infections and septicemia in humans. They are also commonly isolated from colibacillosis in poultry. Studies to determine the similarities of ExPEC from different origins have indicated that avian strains potentially have zoonotic properties.</p> <p>Results</p> <p>A total of 59 ExPEC O1:K1:H7/NM isolates (21 from avian colibacillosis, 15 from human meningitis, and 23 from human urinary tract infection and septicemia) originated from four countries were characterized by phylogenetic PCR grouping, Multilocus Sequence Typing (MLST), Pulsed Field Gel Electrophoresis (PFGE) and genotyping based on several genes known for their association with ExPEC or avian pathogenic <it>Escherichia coli </it>(APEC) virulence.</p> <p>APEC and human ExPEC isolates differed significantly in their assignments to phylogenetic groups, being phylogroup B2 more prevalent among APEC than among human ExPEC (95% vs. 53%, <it>P </it>= 0.001), whereas phylogroup D was almost exclusively associated with human ExPEC (47% vs. 5%, <it>P </it>= 0.0000). Seven virulence genes showed significant differences, being <it>fimAv</it><sub>MT78 </sub>and <it>sat </it>genes linked to human isolates, while <it>papGII</it>, <it>tsh</it>, <it>iron</it>, <it>cvaC </it>and <it>iss </it>were significantly associated to APEC. By MLST, 39 of 40 ExPEC belonging to phylogroup B2, and 17 of 19 belonging to phylogroup D exhibited the Sequence Types (STs) ST95 and ST59, respectively. Additionally, two novel STs (ST1013 and ST1006) were established. Considering strains sharing the same ST, phylogenetic group, virulence genotype and PFGE cluster to belong to the same subclone, five subclones were detected; one of those grouped six strains of human and animal origin from two countries.</p> <p>Conclusion</p> <p>Present results reveal that the clonal group B2 O1:K1:H7/NM ST95, detected in strains of animal and human origin, recovered from different dates and geographic sources, provides evidence that some APEC isolates may act as potential pathogens for humans and, consequently, poultry as a foodborne source, suggesting no host specificity for this type of isolates. A novel and important finding has been the detection of the clonal group D O1:K1:H7/NM ST59 almost exclusively in humans, carrying pathogenic genes linked to the phylogenetic group D. This finding would suggest D O1:K1:H7/NM ST59 as a host specific pathotype for humans.</p
The Bartonian-Priabonian marine record of the eastern South Pyrenean foreland basin (NE Spain): a new calibration of the larger foraminifers and calcareous nannofossil biozonation
This study presents a combined biostratigraphic (calcareous nannofossils, larger foraminifers) and magnetostratigraphic study of the Middle and Late Eocene marine units of the Igualada area, eastern Ebro Basin. The studied sections of Santa Maria de Miralles and La Tossa encompass the complete marine succession of the Santa Maria Group, where assemblages rich in larger foraminifers have been studied since the early 1950âs. A total of 224 paleomagnetic sites and 62 biostratigraphic samples were collected along a 1350m-thick section that ranges from chron C20n to chron C16n (âŒ43Ma to âŒ36Ma). The resulting magnetostratigraphy-based chronology challenges existing chronostratigraphic interpretations of these units and results in a new calibration of the biostratigraphic zonations. The base of calcareous nannofossil Zone NP19-20 is pinned down to an older age than its presently accepted attribution, whereas the time span assigned to Zone NP18 is significantly reduced. A revised calibration of larger foraminifers indicates that Zone SBZ18, formerly assigned exclusively to the late Bartonian, extends its range to the earlymost Priabonian, the Bartonian stage being almost entirely represented by Zone SBZ17. A division of Zone SBZ18 into two subzones is proposed
Preconcentration and sensitive determination of the anti-inflammatory drug diclofenac on a paper-based electroanalytical platform
This work describes the development of a paper-based platform for highly sensitive detection of diclofenac. The quantification of this anti-inflammatory drug is of importance in clinical (e.g. quality and therapeutic control) and environmental (e.g. emerging contaminant determination) areas. The easy-to-handle platform here described consists of a carbon-ink paper-based working electrode and two metallic wires, provided by a gold-plated standard connector, as reference and counter electrodes. The porous paper matrix enables the preconcentration of the sample, decoupling sample and detection solutions. Thus, relatively large sample volumes can be used, which significantly improves the sensitivity of the method. A wide dynamic range of four orders of magnitude, between 0.10 and 100âŻÎŒM, was obtained for diclofenac determination. Due to the predominance of adsorption at the lowest concentrations, there were two linear concentration ranges: one comprised between 0.10 and 5.0âŻÎŒM (with a slope of 0.85âŻÎŒAâŻÎŒM-1) and the other between 5.0 and 100âŻÎŒM (with a slope of 0.48âŻÎŒAâŻÎŒM-1). A limit of detection of 70âŻnM was achieved with this simple device that provided accurate results with an RSD of ca. 5%. The platform was applied for diclofenac quantification in spiked tap water samples. The versatility of this design enabled the fabrication of a multiplexed platform containing eight electrochemical cells that work independently. The low cost, small size and simplicity of the device allow on-site analysis, which is very useful for environmental monitoring.The authors would like to thank the EU and FCT/UEFISCDI/FORMAS for funding, in the frame of the collaborative internationalconsortium REWATERfinanced under the ERA-NET CofundWaterWorks 2015 Call. This ERA-NET is an integral part of the 2016Joint Activities developed by the Water Challenges for a ChangingWorld Joint Programme Initiative (Water JPI). This work was alsosupported by the EU (FEDER funds through COMPETE) and FCT(project FOODnanoHEALTH, Portugal2020, Norte-01-0145-FEDER-000011 and project UID/QUI/50006/2013) and by the SpanishMinistry of Economy and Competitiveness (MINECO, projectCTQ2014-58826-R). EstefanĂa Costa Rama thanks the Governmentof Principado de Asturias and Marie Curie-Cofund Actions for thepost-doctoral grantâClarĂn-CofundâACA17-20.info:eu-repo/semantics/publishedVersio
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