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81.
82.
Infections caused by Extended spectrum β-lactamase (ESBL)-producing E. coli are an emerging global problem, threatening the effectiveness of the extensively used β-lactam antibiotics. ESBL dissemination is facilitated by plasmids, transposons, and other mobile elements. We have characterized the plasmid content of ESBL-producing E. coli from human urinary tract infections. Ten diverse isolates were selected; they had unrelated pulsed-field gel electrophoresis (PFGE) types (<90% similarity), were from geographically dispersed locations and had diverging antibiotic resistance profiles. Three isolates belonged to the globally disseminated sequence type ST131. ESBL-genes of the CTX-M-1 and CTX-M-9 phylogroups were identified in all ten isolates. The plasmid content (plasmidome) of each strain was analyzed using a combination of molecular methods and high-throughput sequencing. Hidden Markov Model-based analysis of unassembled sequencing reads was used to analyze the genetic diversity of the plasmid samples and to detect resistance genes. Each isolate contained between two and eight distinct plasmids, and at least 22 large plasmids were identified overall. The plasmids were variants of pUTI89, pKF3-70, pEK499, pKF3-140, pKF3-70, p1ESCUM, pEK204, pHK17a, p083CORR, R64, pLF82, pSFO157, and R721. In addition, small cryptic high copy-number plasmids were frequent, containing one to seven open reading frames per plasmid. Three clustered groups of such small cryptic plasmids could be distinguished based on sequence similarity. Extrachromosomal prophages were found in three isolates. Two of them resembled the E. coli P1 phage and one was previously unknown. The present study confirms plasmid multiplicity in multi-resistant E. coli. We conclude that high-throughput sequencing successfully provides information on the extrachromosomal gene content and can be used to generate a genetic fingerprint of possible use in epidemiology. This could be a valuable tool for tracing plasmids in outbreaks. 相似文献
83.
Johanna Aponte-González Luisa Fajardo-Bernal Jorge Diaz Javier Eslava-Schmalbach Oscar Gamboa Joel W. Hay 《PloS one》2013,8(11)
Objective
To compare costs and effectiveness of three strategies used against cervical cancer (CC) and genital warts: (i) Screening for CC; (ii) Bivalent Human Papillomavirus (HPV) 16/18 vaccine added to screening; (iii) Quadrivalent HPV 6/11/16/18 vaccine added to screening.Methods
A Markov model was designed in order to simulate the natural history of the disease from 12 years of age (vaccination) until death. Transition probabilities were selected or adjusted to match the HPV infection profile in Colombia. A systematic review was undertaken in order to derive efficacy values for the two vaccines as well as for the operational characteristics of the cytology test. The societal perspective was used. Effectiveness was measured in number of averted Disability Adjusted Life Years (DALYS).Results
At commercial prices reported for 2010 the two vaccines were shown to be non-cost-effective alternatives when compared with the existing screening strategy. Sensitivity analyses showed that results are affected by the cost of vaccines and their efficacy values, making it difficult to determine with certainty which of the two vaccines has the best cost-effectiveness profile. To be ‘cost-effective’ vaccines should cost between 141 and 147 USD (Unite States Dollars) per vaccinated girl at the most. But at lower prices such as those recommended by WHO or the price of other vaccines in Colombia, HPV vaccination could be considered very cost-effective.Conclusions
HPV vaccination could be a convenient alternative for the prevention of CC in Colombia. However, the price of the vaccine should be lower for this vaccination strategy to be cost-effective. It is also important to take into consideration the willingness to pay, budgetary impact, and program implications, in order to determine the relevance of a vaccination program in this country, as well as which vaccine should be selected for use in the program. 相似文献84.
85.
Cesar D. Bordenave Francisco J. Escaray Ana B. Menendez Eva Serna Pedro Carrasco Oscar A. Ruiz Andrés Gárriz 《PloS one》2013,8(12)
Lotus japonicus is a model legume broadly used to study many important processes as nitrogen fixing nodule formation and adaptation to salt stress. However, no studies on the defense responses occurring in this species against invading microorganisms have been carried out at the present. Understanding how this model plant protects itself against pathogens will certainly help to develop more tolerant cultivars in economically important Lotus species as well as in other legumes. In order to uncover the most important defense mechanisms activated upon bacterial attack, we explored in this work the main responses occurring in the phenotypically contrasting ecotypes MG-20 and Gifu B-129 of L. japonicus after inoculation with Pseudomonas syringae DC3000 pv. tomato. Our analysis demonstrated that this bacterial strain is unable to cause disease in these accessions, even though the defense mechanisms triggered in these ecotypes might differ. Thus, disease tolerance in MG-20 was characterized by bacterial multiplication, chlorosis and desiccation at the infiltrated tissues. In turn, Gifu B-129 plants did not show any symptom at all and were completely successful in restricting bacterial growth. We performed a microarray based analysis of these responses and determined the regulation of several genes that could play important roles in plant defense. Interestingly, we were also able to identify a set of defense genes with a relative high expression in Gifu B-129 plants under non-stress conditions, what could explain its higher tolerance. The participation of these genes in plant defense is discussed. Our results position the L. japonicus-P. syringae interaction as a interesting model to study defense mechanisms in legume species. 相似文献
86.
87.
Oscar Ortega-Recalde Dora Janeth Fonseca Liliana Catherine Patiño Juan Jaime Atuesta Carolina Rivera-Nieto Carlos Martín Restrepo Heidi Eliana Mateus Marjo S. van der Knaap Paul Laissue 《Mitochondrion》2013,13(6):749-754
NDUFV1 mutations have been related to encephalopathic phenotypes due to mitochondrial energy metabolism disturbances. In this study, we report two siblings affected by a diffuse leukodystrophy, who carry the NDUFV1 c.1156C>T (p.Arg386Cys) missense mutation and a novel 42-bp deletion. Bioinformatic and molecular analysis indicated that this deletion lead to the synthesis of mRNA molecules carrying a premature stop codon, which might be degraded by the nonsense-mediated decay system. Our results add information on the molecular basis and the phenotypic features of mitochondrial disease caused by NDUFV1 mutations. 相似文献
88.
Oscar Lamas Longarela Tobias T. Schmidt Katrin Sch?neweis Raffaella Romeo Heiner Wedemeyer Stephan Urban Andreas Schulze 《PloS one》2013,8(3)
The hepatitis delta virus (HDV) is a small, defective RNA virus that requires the presence of the hepatitis B virus (HBV) for its life cycle. Worldwide more than 15 million people are co-infected with HBV and HDV. Although much effort has been made, the early steps of the HBV/HDV entry process, including hepatocyte attachment and receptor interaction are still not fully understood. Numerous possible cellular HBV/HDV binding partners have been described over the last years; however, so far only heparan sulfate proteoglycans have been functionally confirmed as cell-associated HBV attachment factors. Recently, it has been suggested that ionotrophic purinergic receptors (P2XR) participate as receptors in HBV/HDV entry. Using the HBV/HDV susceptible HepaRG cell line and primary human hepatocytes (PHH), we here demonstrate that HDV entry into hepatocytes depends on the interaction with the glycosaminoglycan (GAG) side chains of cellular heparan sulfate proteoglycans. We furthermore provide evidence that P2XR are not involved in HBV/HDV entry and that effects observed with inhibitors for these receptors are a consequence of their negative charge. HDV infection was abrogated by soluble GAGs and other highly sulfated compounds. Enzymatic removal of defined carbohydrate structures from the cell surface using heparinase III or the obstruction of GAG synthesis by sodium chlorate inhibited HDV infection of HepaRG cells. Highly sulfated P2XR antagonists blocked HBV/HDV infection of HepaRG cells and PHH. In contrast, no effect on HBV/HDV infection was found when uncharged P2XR antagonists or agonists were applied. In summary, HDV infection, comparable to HBV infection, requires binding to the carbohydrate side chains of hepatocyte-associated heparan sulfate proteoglycans as attachment receptors, while P2XR are not actively involved. 相似文献
89.
Germinal J. Canto Alarcon Yezenia Rubio Venegas Luis Bojorquez Narvaez Oscar E. Pizano Martínez Leticia García Casanova Susana Sosa Gallegos Alejandro Nava Vargas Andrea M. Olvera Ramírez Feliciano Milian Suazo 《PloS one》2013,8(10)
“Test-and-slaughter” has been successful in industrialized countries to control and eradicate tuberculosis from cattle; however, this strategy is too expensive for developing nations, where the prevalence is especially high. Vaccination with the Calmette-Guérin (BCG) strain has been shown to protect against the development of lesions in vaccinated animals: mouse, cattle and wildlife species. In this study, the immune response and the pathology of vaccinated (BCG-prime and BCG prime-CFP-boosted) and unvaccinated (controls) calves were evaluated under experimental settings. A 106 CFU dose of the BCG strain was inoculated subcutaneously on the neck to two groups of ten animas each. Thirty days after vaccination, one of the vaccinated groups was boosted with an M. bovis culture filtrate protein (CFP). Three months after vaccination, the three groups of animals were challenged with 5×105 CFU via intranasal by aerosol with a field strain of M. bovis. The immune response was monitored throughout the study. Protection was assessed based on immune response (IFN-g release) prechallenge, presence of visible lesions in lymph nodes and lungs at slaughter, and presence of bacilli in lymph nodes and lung samples in histological analysis. Vaccinated cattle, either with the BCG alone or with BCG and boosted with CFP showed higher IFN-g response, fewer lesions, and fewer bacilli per lesion than unvaccinated controls after challenge. Animals with low levels of IFN-g postvaccine-prechallenge showed more lesions than animals with high levels. Results from this study support the argument that vaccination could be incorporated into control programs to reduce the incidence of TB in cattle in countries with high prevalence. 相似文献
90.
Andrés Solórzano Mónica Núñez-Flores Oscar Inostroza-Michael Cristián E. Hernández 《Palaeontology》2020,63(3):415-429
Species diversity patterns are governed by complex interactions among biotic and abiotic factors over time and space, but are essentially the result of the diversification dynamics (differential speciation and extinction rates) over the long-term evolutionary history of a clade. Previous studies have suggested that temporal variation in global temperature drove long-term diversity changes in Crocodylia, a monophyletic group of large ectothermic organisms. We use a large database of crocodylian fossil occurrences (192 spp.) and body mass estimations, under a taxic approach, to characterize the global diversification dynamics of crocodylians since the Cretaceous, and their correlation with multiple biotic and abiotic factors in a Bayesian framework. The diversification dynamic of crocodylians, which appears to have originated in the Turonian (c. 92.5 Ma), is characterized by several phases with high extinction and speciation rates within a predominantly low long-term mean rate. Our results reveal long-term diversification dynamics of Crocodylia to be a highly complex process driven by a combination of biotic and abiotic factors which influenced the speciation and extinction rates in dissimilar ways. Higher crocodylian extinction rates are related to low body mass disparity, indicating selective extinctions of taxa at both ends of the body mass spectrum. Speciation rate slowdowns are noted when the diversity of the clade is high and the warm temperate climatic belt is reduced. Our finding supports the idea that temporal variations of body mass disparity, self-diversity, and the warm climate belt size provided more direct mechanistic explanations for crocodylian diversification than do proxies of global temperature. 相似文献