Dissertations / Theses on the topic 'MLSE'
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Hart, Brian. "MLSE diversity receiver structures." Thesis, University of Canterbury. Electrical and Electronic Engineering, 1996. http://hdl.handle.net/10092/6033.
Full textCovre, Marcos Ricardo. "Redução de estados em receptores MLSE para comunicações ópticas." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259807.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Sistemas ópticos são afetados pelas dispersões cromática e de modo de polarização que causam interferência intersimbólica. Para mitigar essas dispersões é utilizado um receptor de sequência de máxima verossimilhança, com uma métrica subótima adequada para esse sistema. Nesta dissertação uma técnica de redução de estados da treliça do algoritmo de Viterbi é descrita e adaptada para um sistema óptico de modulação por intensidade e detecção direta. A métrica é adaptada para compensar o efeito da redução de estados pela técnica de delayed-decision feedback sequence estimation. Resultados são apresentados em sistemas com dispersão cromática e de modo de polarização
Abstract: Optical systems are affected by chromatic and polarization mode dispersion causing intersymbol interference. To mitigate these dispersions a maximumlikelihood sequence estimation receiver is used, with an appropriate suboptimal metric for this system. In this thesis a technique for reducing the number of states of the trellis of the Viterbi algorithm is described and adapted to an optical intensity modulation and direct detection. The metric is adapted to compensate for the effect of reducing the number of states by the technique of delayed-decision feedback sequence estimation. Results are presented for a system with chromatic and polarization mode dispersions
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
Zhou, Li. "Low Complexity PSP-MLSE receiver for H-CPM with receive diversity." Thesis, University of Canterbury. Department of Electrical and Computer Engineering, 2009. http://hdl.handle.net/10092/4455.
Full textSawada, Manabu, Masaaki Katayama, Takaya Yamazato, and Akira Ogawa. "Effect of Nonlinear Amplification on a Spread Spectrum Signal and Receiver Configurations." IEICE, 1994. http://hdl.handle.net/2237/7201.
Full textMoctezuma, Andres. "CPM Equalization to Compensate for ISI due to Band Limiting Channels." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/34559.
Full textWe propose two approaches to the problem of equalization of band-limited CPM signals. First, our efforts are focused on shortening the channel impulse response so that we can use a low complexity MLSE equalizer. We implement the channel truncation structure by Falconer and Magee and adapt it to work with CPM signals. This structure uses a, a more derivable, pre-filter to shape the overall response of the channel, so that its impulse response is of shorter duration. Simulation results show that near-MLSE performance can be obtained while dramatically reducing MLSE equalizer complexity.
In our second approach, we focus on eliminating the group-delay variations inside the channel passband using an FIR pre-filter. We assume the channel to be time-invariant and provide a method to design an FIR filter so that -when convolved with the band limiting filter - it results in more constant group-delay over the filter passband. Results show that eliminating the group-delay variations in the band limiting filter passband reduce the amount of ISI and improve bit error rate performance.
Master of Science
McCorduck, James A., and Kamilo Feher. "SPECTRAL EFFICIENCY/BIT ERROR RATE OF FQPSK AND OTHER NON-COHERENT SYSTEMS SUPERIOR TO COHERENT SYSTEMS FOR SMS AND BURSTED TDMA AND CDMA SYSTEMS." International Foundation for Telemetering, 2002. http://hdl.handle.net/10150/606360.
Full textFor faster acquisition in bursted environments for SMS (Short Messaging Service) and other lower-bit rate applications, non-coherent detection techniques are proposed. Non-Coherent detection demodulators are proposed because faster acquisition capability in bursted environments can result in a reduced amount of preamble bits in the messaging frame, i.e. less overhead, resulting in an effective increase in spectral efficiency. Reducing the preamble can also provide performance enhancement opportunities for Feher Quadrature Phase Shift Keying (FQPSK) [1] and for other systems. The preamble can also be varied to provide for better Bit Error Rate (BER) performance. The lower bit rate environment also gives the opportunity to employ simpler architectures in lieu of preamble modification. Several non-coherent detection alternatives are described.
Deshpande, Nikhil 1978. "Matlab implementation of GSM traffic channel [electronic resource] / by Nikhil Deshpande." University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000167.
Full textDocument formatted into pages; contains 62 pages
Thesis (M.S.E.E.)--University of South Florida, 2003.
Includes bibliographical references.
Text (Electronic thesis) in PDF format.
ABSTRACT: The GSM platform is a extremely successful wireless technology and an unprecedented story of global achievement. The GSM platform is growing and evolving and offers an expanded and feature-rich voice and data enabling services. General Packet Radio Service, (GPRS), will have a tremendous transmission rate, which will make a significant impact on most of the existing services. Additionally, GPRS stands ready for the introduction of new services as operators and users, both business and private, appreciate the capabilities and potential that GPRS provides. Services such as the Internet, videoconferencing and on-line shopping will be as smooth as talking on the phone. Moreover, the capability and ease of access to these services increase at work, at home or during travel. In this research the traffic channel of a GSM system was studied in detail and simulated in order to obtain a performance analysis. Matlab, software from Mathworks, was used for the simulation.
ABSTRACT: Both the forward and the reverse links of a GSM system were simulated. A flat fading model was used to model the channel. Signal to Noise Ratio, (SNR), was the primary metric that was varied during the simulation. All the building blocks for a traffic channel, including a Convolutional encoder, an Interleaver and a Modulator were coded in Matlab. Finally the GPRS system, which is an enhancement of the GSM system for data services was introduced.
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Lin, Jin-Son, and Kamilo Feher. "NONCOHERENT AND DIFFERENTIAL DETECTION OF FQPSK WITH MAXIMUM-LIKELIHOOD SEQUENCE ESTIMATION IN NONLINEAR CHANNELS." International Foundation for Telemetering, 2002. http://hdl.handle.net/10150/606381.
Full textThis paper presents noncoherent limiter-discriminator detection and differential detection of FQPSK (Feher quadrature phase-shift-keying) with maximum-likelihood sequence estimation (MLSE) techniques. Noncoherent FQPSK systems are suitable for fast fading and cochannel interference channels and channels with strong phase noise, and they can offer faster synchronization and reduce outage events compared with conventional coherent systems. In this paper, both differential detection and limiter-discriminator detection of FQPSK are discussed. We use MLSE with lookup tables to exploit the memory in noncoherently detected FQPSK signals and thus significantly improve the bit error rate (BER) performance in an additive white Gaussian noise (AWGN) channel.
Deshpande, Nikhil. "Matlab implementation of GSM traffic channel." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000167.
Full textOzgur, Ayfer. "Performance Of A Transmit Delay Scheme In Digital Simulcast Environment." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605179/index.pdf.
Full text#960
/4 DQPSK receiver and the results show that the proposed scheme operates succesfully, turning destructive interference disadvantage into a multipath diversity advantage, provided that a sufficient delay is used between the base stations. The &ldquo
sufficient&rdquo
delay value is determined by considering the coverage properties of the scheme and is in fact &ldquo
optimum&rdquo
, since more than sufficient transmit delays result in useless increased receiver complexity. We provide our results using parameters for the TETRA system, however, the results of the work can readily be used for other systems.
Sallem, Soumaya. "Traitements de réception mono et multi-antennes de signaux rectilignes ou quasi-rectilignes en présence de multitrajets de propagation." Thesis, Evry, Institut national des télécommunications, 2012. http://www.theses.fr/2012TELE0054/document.
Full textThe SAIC/MAIC (Single/Multiple Antenna Interference Cancellation) receiver, recently introduced, is able to separate up to 2N synchronous users with N antennas for the radiocommunications networks using rectilinear or quasi-rectilinear modulations. A such receiver, operational in GSM handsets since 2006, exploits the second order non-circularity of signals and gives rise to an optimal widely linear (WL) filter. This receiver has been shown to be powerful for synchronous users without any frequency offsets (for example Doppler shift), but its behaviour in the presence of asynchronous users having potentially non zero carrier residues, omnipresent in many radio applications, has not yet been the subject of theoretical studies, which doesn't allow us to know their damage. For this reason, the purpose of the first part of this work is to present an analysis of SAIC/MAIC receiver performances, implemented via an MMSE approach with training sequence, with two users not necessarily synchronized with frequency shifts. To simplify the analytical developments, we limited the theoretical analysis to some particular cases with rectilinear modulations. Hence, simple and interpretable analytical expressions were given and analyzed. We proved in particular that the performance is less degraded in the case of a shift on the useful than in the presence of a drift on the jammer. Furthermore, the degradation increases with desynchronization of the two signals. To precise the range of validity of analytical approximations, numerical illustrations were made using as parameters those of the GSM standard in order to apply this study to this standard in particular and cellular networks in general. Extending the analysis to quasi-rectilinear modulations had required the implementation of a spatio-temporal filtering. We have studied the impact of the size of the spatio-temporal filter on the performance of MMSE SAIC/MAIC receiver for quasi-rectilinear modulations (GMSK and MSK) in the presence of residual frequencies. The study reveals that with standard carrier residues, this receiver remains relatively robust and doesn't require a compensation. The second part of this work considers frequency-selective channels and is developing a SIMO MLSE receiver for a useful signal with any linear modulation in the presence of an additive Gaussian centered stationary temporally and spatially colored and potentially non-circular noise, starting from a general problem of detection of a waveform. We have shown that SIMO MLSE receiver consists of a WL filter, a sampler at the symbol rate and a recursive minimization of a metric that can be solved by the Viterbi algorithm. The case of quasi-rectilinear modulations is also considered. Within this framework, we had proved that the SIMO MLSE receiver has the same structure through a postreatment derotation. All these filters are interpreted as WL multidimensional matched filters (WL MMF) in the sense that they maximize the SNR of the current symbol at output. Then, we extended the MLSE receiver structure developed in case of a noncircular gaussian noise but this time cyclostationary, so as to approximate radio cellular applications. We call this new receiver "pseudo-MLSE" because its structure was imposed. By conjecturing that the performances by per symbol error probability are directly related to the SNR of the current symbol, general expressions of this SNR are given for MLSE and pseudo MLSE receivers with stationary and cyclostationary potentially noncircular interferences. Interpretable formulas of these SNR were given in special cases and numerical simulations were presented to show performance gains of the receivers we have introduced relative to conventional MLSE receivers derived under the assumption of circular stationary noise
Teal, Paul D., and p. teal@irl cri nz. "Real Time Characterisation of the Mobile Multipath Channel." The Australian National University. Research School of Information Sciences and Engineering, 2002. http://thesis.anu.edu.au./public/adt-ANU20020722.085502.
Full textGomes, Catarina dos Santos Teles. "Identification and phylogenetic characterization of Ralstonia solanacearum species complex isolates collected in Portugal." Master's thesis, ISA, 2017. http://hdl.handle.net/10400.5/15089.
Full textUgurlu, Bilal. "Receiver Design For A Class Of New Pulse Shapes For Cpm Signals." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614093/index.pdf.
Full textZamiri-Jafarian, Hossein. "Adaptive MLSDE receivers for wireless communications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/NQ41537.pdf.
Full textAfonso, Mendes-Yahiaoui Noura. "Épidémiologie moléculaire du complexe d’espèces Ralstonia solanacearum, agent du flétrissement bactérien, dans les îles du Sud-Ouest de l’océan Indien." Thesis, La Réunion, 2018. http://www.theses.fr/2018LARE0014.
Full textIn the southwest Indian Ocean (SWIO) islands (Comoros, Mauritius, Mayotte, Réunion, Rodrigues and Seychelles), bacterial wilt caused by the Ralstonia solanacearum species complex (Rssc) is considered one of the most harmful plant disease for food crops or export. The main objective of this work presented in this manuscript was to explore the level and the distribution of the genetic diversity of Rssc and the genetic structure of its populations in SWIO. We conducted extensive sampling campaigns that resulted in a large collection of 1704 isolates, mainly from Solanaceae (tomato, potato, chilli, eggplant, pepper) and geranium rosat. The phylogenetic assignment of the isolates showed a very high prevalence of phylotype I (88 %), which is distributed in each island of the SWIO, while phylotypes II (9 %) and III (3 %) are found only in Réunion. Two phylotype IV strains have also been reported in Mauritius, representing the first report of this phylogenetic group in SWIO. A phylogenetic and genotyping approach (MLSA/MLST) based on sequence analysis of 6 housekeeping genes and 1 gene associated with virulence (egl) revealed the genetic relationships between 145 representative SWIO strains (geographic diversity + host) and 90 global reference strains. The development and application of MLVA scheme based on 17 variable number of tandem repeat sequences (VNTR) on nearly 1300 strains revealed that phylotype I populations are organized into clonal complexes in SWIO and that the level of genetic diversity is highly contrasted according to the islands, with Mauritius having the highest genetic diversity. This work highlights the deployment of a genetic lineage (Sequevar I-31, STI-13, MT-035), overrepresented in SWIO islands, which could have been introduced via contaminated plant material from South Africa or West Africa. Our preliminary studies show that the main haplotype MT-035 (i) is the probable founding haplotype of the most prevalent clonal complex in SWIO, (ii) has high pathogenicity (wide range of hosts including cultivated plants and weeds, and high aggressiveness on Solanaceae) and (iii) has a strong ability to compete in the environment via the production of bacteriocins. This work will ultimately strengthen epidemiosurveillance and guide control strategies of this plant pathogen, including the deployment of resistant cultivars
Mary, Philippe. "Etude analytique des performances des systèmes radio-mobiles en présence d'évanouissements et d'effet de masque." Phd thesis, INSA de Lyon, 2008. http://tel.archives-ouvertes.fr/tel-00406310.
Full textSALLEM, Soumaya. "Traitements de réception mono et multi-antennes de signaux rectilignes ou quasi-rectilignes en présence de multitrajets de propagation." Phd thesis, Institut National des Télécommunications, 2012. http://tel.archives-ouvertes.fr/tel-00814611.
Full textDiBenedetto, Michael F. "Citing criteria for the microwave landing system (MLS) MLS/ILS collocation and runway hump shadowing." Ohio : Ohio University, 1988. http://www.ohiolink.edu/etd/view.cgi?ohiou1182785020.
Full textDiBenedetto, Michael F. "Siting criteria for the microwave landing system (MLS): MLS/ILS collocation and runway hump shadowing." Ohio University / OhioLINK, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1182785020.
Full textFarrow, Kylie Ann 1973. "Analysis of clostridial MLS resistance determinants." Monash University, Dept. of Microbiology, 2001. http://arrow.monash.edu.au/hdl/1959.1/8319.
Full textPrezotto, Leandro Fontes. "Tipificação de linhagens de Wolbachia do complexo Anastrepha fraterculus (Diptera: Tephritidae) da região neotropical por análise de locos múltiplos." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/41/41131/tde-23072013-145455/.
Full textWolbachia is an intracellular bacteria found in somatic and in the reproductive tissues of various arthropods and nematodes. Phylogenetic studies based on 16S and ftsZ genes indicated the existence of six Wolbachia taxonomic supergroups (\"A\" through \"F\"). Infection of Wolbachia have been linked to several changes in the reproduction of their hosts, like cytoplasmic incompatibility (CI), parthenogenesis, feminization of genetic males and male killing. T Wolbachia infection has been described in several species of fruit flies of the family Tephritidae, like Bactrocera ascita, Rhagoletis cerasi, Ceratitis capitata, in which the bacteria induces cytoplasmic incompatibility. In Anastrepha, endemic to the American Continent, Wolbachia infection has been described in several species by analysis of the wsp gene, and there is also indications that Wolbachia-mediated CI occurs in two species of the fraterculus group. The occurrence of CI coupled with the suggestion of the use of Wolbachia in population supression programs, impose the need for a more precise characterization of the different strains of Wolbachia. The identification of the different strains of the bacteria is most accurate when the methodology of multiple loci (MLST) is applied. In this study fragments of genes gatB, coxA, hcpA, ftsZ and fbpA, integrating the methodology MLST, and of wsp gene were amplified and sequenced. Population samples of the Anastrepha fraterculus.complex of cryptic species from Brasil, Argentina, Peru, Ecuador, Colombia, Guatemala and Mexico, and samples of A. oblique from Basil were analysed. All samples were infected with supergroup \"A\" Wolbachia. For each of the five MLST genes, unique as well already known haplotypes were found. Phylogenetic analyses of each gene isolated showed incongruences in the relationships among haplotypes and population samples. The concatenated sequences of the five genes, with 2079 bp, were analyzed and 20 haplotypes were found, with distances ranging from 0.001 to 0.058. Phylogenetic analysis of Wolbachia isolated haplotypes into distinct clades, demonstrating that different strains of Wolbachia were present in these hosts, and in distinct geographic areas. Hosts specific haplotypes were found as well as more than one strain of Wolbachia was found in given population samples. A haplotypes (ST1) was detected in two species of the complex and is also the most commonly found in different organisms. Twenty two different sequences of about 500 bp were found for the wsp gene. The level of nucleotide variability is not uniform along the gene, forming a pattern with four hypervariable regions, HVRs. Genetic distances between haplotypes showed a variation from 0.001 to 0.235. Phylogenetic analysis of the haplotypes also isolated Wolbachia into distinct clades, but in contrast to the MLST, the tree formed by wsp gene does not support the monophily of some groups. The data show that strains of Wolbachia are disseminated along the American Continent, and also that there are specific strains in determined geographic areas. Analyses of ovaries and testes from infected and non infected (cured by heat treatment) individuals of A. sp. 1 and A. obliqua were made in search of possible effects of Wolbachia on its hosts. Ovaries from infected and cured females of both species, stained by DAPI, showed no visible differences in this morphological analysis. The production of sperms increases during few days after ermergence and drops out later one. Analysis of infected and cured males showed that the production of sperms were not significant between them, for both the host species. Fecundity of infected females of A, sp.1 was significantly higher than that of cured females, but was similar in A. obliqua, Egg hatching was scored in compatible intraspecies crosses and also in incompatibles crosses, of both species. Fertility was significntly higher for infected females of both species. Infected males of both species were found associated to crosses in which the higher egg hatching was observed. Analyses of incompatible crosses showed that CI occurred at high rates in A. sp.1 (CI = 54.01%) and in A. obliqua (CI = 66.2%). The data suggest that an incipient mutualism may be present in the relationships of Wolbachia and its Anastrepha hosts
Silva, Ketrin Cristina da. "Caracterização molecular de plasmídeos carreadores de genes codificadores de beta-lactamases de espectro estendido em Enterobactereaceas isoladas de suínos." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/10/10134/tde-03062016-151301/.
Full textExtended-spectrum beta-lactamase production (ESBL) became a great challenge regarding public health because limit the therapeutic options to treat infections by gram-negative bacteria. The aim of this study were evaluate the occurrence of ESBL producers in Brazilian swine farms and characterize blaESBL-carrying plasmids by sizing and incompatibility group and presence of additional resistance genes. Strains were isolated in MacConkey agar and identified by Maldi-Tof. Next, the minimal inhibitory concentration values were determined by microdilution and/or agar dilution to aminoglycosides, carbapenems, cephalosporins, fluoroquinolones, tetracyclines, sulfas and cephalosporin/inhibitors association. Betalactamase encoding genes, plasmid incompatibility group and Escherichia coli phylogenetic group were determined by PCR. Clonal relatedness was evaluated by ERIC-PCR and MLST. Finally, the blaCTX-M-15 genetic environment was determined by PCR and/or sequencing and blaESBL-carrying plasmids transferred to E. coli TOP10 and C600 receptor strains by transformation and conjugation, respectively, and partially sequenced. CTX-M-2-producing E. coli were the most prevalent phenotype, which were endemic in Minas Gerais State. Moreover, the CTX-M-15 enzyme emerged among E. coli (ST224, ST410, ST1284), Klebsiella pneumoniae, Enterobacter cloacae e Pseudomonas aeruginosa (ST3201) strains. The blaCTX-M-15 was associated with IncF plasmids, which were successfully transferred to E.coli TOP10, similarly, IncF plasmids were found harboring the blaCTX-M-2. The blaCTX-M-8, detected in four novel E. coli sequence types (ST5845, ST5847, ST5848 e ST5350), was not acquired by receptor strains. Thus, the surveillance of resistant phenotypes in swine production must be established as a priority as well as narrow spectrum antimicrobials prescription antimicrobial instead broad spectrum to prevent the dissemination of these phenotypes in farms and their transmission to human population.
Silva, Keila de Cássia Ferreira de Almeida. "Caracterização de Pseudomonas aeruginosa encontradas colonizando e/ou infectando pacientes queimados internados em um hospital público da cidade do Rio de Janeiro." Niterói, 2017. https://app.uff.br/riuff/handle/1/3038.
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Pseudomonas aeruginosa é um dos principais patógenos causadores de infecções graves em pacientes queimados, estando associado a elevadas taxas de mortalidade e morbidade. A alta plasticidade de seu genoma confere a este microrganismo a capacidade de tornar-se multirresistente a antimicrobianos, dificultando o tratamento devido à redução de opções terapêuticas. Este estudo teve como objetivo analisar 35 cepas de P. aeruginosa isoladas de pacientes queimados e da mesa onde era realizada a balneoterapia em um centro de tratamento de queimados (CTQ), determinando o perfil de resistência aos antimicrobianos, os fatores genéticos relacionados à virulência e resistência antimicrobiana, a capacidade de produzir biofilme e ação de biocidas sobre o mesmo, além de realizar tipificação molecular das cepas envolvidas. A suscetibilidade antimicrobiana foi verificada utilizando o método de disco-difusão, segundo os critérios do Clinical and Laboratory Standards Institute (CLSI). A pesquisa de genes de resistência que codificassem β-lactamases (blaPER-1, blaCTX-M, blaOXA-10, blaGES-1, blaVIM, blaIMP, blaSPM-1, blaKPC, blaNDM e blaSIM) e dos genes de virulência exoS e exoU, foi realizada através da técnica de Polymerase Chain Reaction (PCR). O teste fenotípico Carba NP, foi utilizado com a finalidade de detectar atividade hidrolítica enzimática à carbapenemas. A capacidade de formação de biofilme foi avaliada em placa para microtitulação e em cupom de aço inoxidável, sendo este último utilizado para verificar a eficácia de três agentes biocidas (hipoclorito de sódio 1%, peróxido de hidrogênio 5% e clorexidina 4%) na remoção dos biofilmes formados. As cepas foram tipificadas através da técnica de Multilocus Sequence Typing (MLST). De acordo com o teste de suscetibilidade antimicrobiana, foi observado um elevado padrão de resistência, com 71,5% (25/35) das cepas sendo resistentes a multidrogas (MDR). O maior percentual de resistência foi para o ciprofloxacino (94,3%; 33/35), seguido da gentamicina (88,6%; 31/35). Também foi observada resistência aos β-lactâmicos, inclusive à carbapenemas (22,9%; 8/35). Com relação aos genes de resistência pesquisados foi encontrado em 34,3% (12/35) das cepas o blaGES-1 e em uma única cepa o blaCTX-M. Nenhum gene codificador de carbapenemases pesquisado foi encontrado. Da mesma forma, nenhuma atividade hidrolítica enzimática ao imipenem foi detectada através do teste Carba NP, sugerindo que outros mecanismos de resistência possam estar envolvidos, como superexpressão de bomba e perda de porina de membrana externa (OprD). O gene de virulência exoS foi o mais prevalente estando presente em 71,4% (25/35) das cepas, enquanto o gene exoU foi detectado em 14,3% (5/35), porém todas as cepas que abrigavam este gene eram carbapenemas resistentes. Onze (31,4%) das 35 cepas, foram formadoras de biofilme utilizando a placa de microtitulação, sendo estas em sua maioria (81,8%) pertencentes ao clone A (obtido através de tipificação por PFGE em estudo prévio), o qual era o mais prevalente infectando/colonizando pacientes e contaminando a mesa de balneoterapia. A remoção do biofilme formado em superfície de cupom de aço inoxidável foi eficaz para os três biocidas testados (hipoclorito de sódio 1%, peróxido de hidrogênio 5% e clorexidina 4%), não havendo contagem de células viáveis das cepas analisadas após contato com os mesmos. A tipificação por MLST originou dois tipos de sequenciamentos novos, ST2236 e ST2237. Conclui-se com este estudo, que a redução de opções terapêuticas associada à presença de genes de virulência, pode agravar a situação destes pacientes. Assim como a presença de genes como blaGES-1 e blaCTX-M é preocupante, pois podem ser difundidas entre as demais cepas por transmissão horizontal, se não houver um controle adequado. Entretanto, o teste de remoção dos biofilmes mostrou que se a desinfecção for realizada de maneira correta, a contaminação cruzada entre pacientes pode ser evitada.
Pseudomonas aeruginosa is major causative pathogens of serious infections in burn patients and is associated with high mortality and morbidity rates. The high plasticity of its genome confers to this organism the ability to become multiresistant to antibiotics, difficulting the threathment due to reduced therapeutic options. This study aimed to analyze 35 strains of P. aeruginosa isolated from burn patients and the tank where balneotherapy was held in a burn treatment center (BTC), determining the resistance profile to antimicrobial agents, genetic factors related to virulence and antimicrobial resistance, the ability to produce biofilms and biocide action thereon and perform molecular typing of the strains involved. Antimicrobial susceptibility was assessed using the disk diffusion method, according to the criteria of the Clinical and Laboratory Standards Institute (CLSI). The research for resistance genes encoding β-lactamases (blaPER-1, blaCTX-M, blaOXA-10, blaGES-1, blaVIM, blaIMP, blaSPM-1, blaKPC, blaNDM and blaSIM) and the virulence genes exoS and exoU was performed using the Polymerase Chain Reaction (PCR). The phenotypic test Carba NP, was used in order to detect enzymatic hydrolytic activity to carbapenems. Biofilm formation ability was evaluated through plate for microtitration and stainless steel coupon, the latter being used to verify the efficacy of three biocides (sodium hypochlorite 1%, hydrogen peroxide 5% and chlorhexidine 4%) to remove formed biofilms. The strains were typed by Multilocus Sequence Typing technique (MLST). According to the antimicrobial susceptibility test, a high resistance pattern was observed in which 71.5% (25/35) of strains were multidrug resistant (MDR). The highest percentage of resistance was to ciprofloxacin (94.3%; 33/35), followed by gentamicin (88.6%; 31/35). It was also observed resistance to β-lactams antibiotics, including the carbapenems (22.9%; 8/35). Regarding the resistance genes investigated were found the blaGES-1 in 34,3% (12/35) of the strains and the blaCTX-M in a single strain. None of the searched genes encoding carbapenemases was found. Similarly, no enzymatic hydrolytic activity to imipenem was detected by Carba NP test, suggesting that other resistance mechanisms may be involved, such as pump over expression and loss of outer membrane porin (OprD). The exoS virulence gen was the most prevalent being present in 71.4% (25/35) of the strains, while exoU was detected in 14.3% (5/35), however all strains that harbored this gene were carbapenems resistant. Eleven (31.4%) of 35 isolates were biofilm formers using the plate for microtitration, which mostly (81.8%) belonging to clone A (obtained in a previous study by PFGE) that was the most prevalent infecting/ colonizing patients and contaminating balneotherapy tank. Removal of biofilm formed in stainless steel coupon surface was effective for all three biocides tested (sodium hypochlorite 1%, hydrogen peroxide 5% and chlorhexidine 4%), with no viable cell count after contact with biocides solutions. The MLST originated two new sequencing types, ST2236 and ST2237. It is concluded from this study that the reduction of therapeutic options associated with the presence of virulence genes, can aggravate the situation of these patients. As well as the presence of genes as blaGES-1 and blaCTX-M is worrying as they may be spread among the other strains by horizontal transmission, if there is no adequate control. However, the removal test of biofilms showed that, if the disinfection is carried out in a correct way, cross-contamination between patients can be avoided.
Ramos, Patrícia Locosque. "Taxonomia do gênero Stenotrophomonas através de Multi Locus Sequence Analysis (MLSA)." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-26012012-170618/.
Full textThe genus Stenotrophomonas is found in the respiratory treatment of patients with chronic pulmonary and also in the rizhosfera of plants. It presents resistance to several antibiotics, promotes the growth of plants and some species present the ability to fix atmospheric nitrogen. The Multi Locus Sequence Analysis (MLSA) is a methodology based on constitutive genes for definition and taxonomic allocation of new species. The general objective of the present work was to characterize a wide collection constituted by Stenotrophomonas from isolated endophytic, type and reference strains. In such a way, a system of classification and identification of Stenotrophomonas by means of MLSA was established. It was possible through the MLSA methodology to define 9 new species, to detect the presence of a new genus and to establish an online system for Stenotrophomonas taxonomy.
Sacramento, Andrey Guimarães. "Caracterização molecular de Enterococcus spp. resistentes à vancomicina em amostras clínicas, ambientes aquáticos e alimentos." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-09112015-155733/.
Full textEnterococci are ubiquitous in the environment and in the intestinal tract of humans and animals. The importance of these bacteria has been associated with nosocomial infection and multiple resistance to antimicrobial agents, mainly vancomycin. The aim of the present study was to perform molecular characterization of vancomycin-resistant Enterococcus spp. strains (VRE) isolated from hospitalized patients, surface water of urban rivers and retail chicken meat in Brazil. The presence of the vanA gene was confirmed in 20 multidrug-resistant strains isolated in 1997-2011. Among these VRE isolates, (n = 12) were identified as E. faecium and (n = 8) as E. faecalis. E. faecium strains isolated from water and clinical samples were classified as clonally related by PFGE, the predominant virulence profile being (acm+, esp+). Additionally, while E. faecium strains isolated from rivers belonging to ST203, ST412 and ST478 (previously characterized as endemic in Brazilian hospitals), new STs were identified among strains of E. faecalis (ST614, ST615 and ST616) and E. faecium (ST953 and ST954) isolated from food. Complete sequences of transposon Tn1546 from VREfm clinical strain 320/07 (ST478) and environmental strain VREfm 11 (ST412) showed a Tn1546-like element of ~12800 bp, with T7698C vanA and G8234T vanX mutations. Moreover, deletion of the Tn1546 left extremity, and the IS1251 and IS1216E sequence inside the vanHS and vanYX intergenic region, respectively, were also detected. In this regard, the IS1216E sequence inside the vanXY intergenic region constitutes a gene array previously reported for Brazilian VREfm clinical strains alone, denoting a regional characteristic. IS1216E has been associated with tcrB and aadE genes, which confer resistance to copper and aminoglycosides, in E. faecium and Streptococcus agalactiae, respectively. Therefore, IS1216E should contribute to rapid acquisition of antimicrobial resistance among species of the clinically important Gram-positive cocci. On the other hand, Tn1546-like elements were identical among clinical and environmental VREfm isolates, suggesting sharing of a common vancomycin resistance gene pool.
Thickett, Kathleen Mary. "Towards developing a multilocus sequence typing (MLST) scheme for Burkholderia cepacia complex." Thesis, University of Warwick, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403134.
Full textLallemand, Marie-Gabrielle. "La lettre dans le recit : etude de l'oeuvre de mlle de scudery." Caen, 1996. http://www.theses.fr/1996CAEN1211.
Full textA traditional narrative ornament of the xvii century, the letter, is examined in this study in view of defining both its role as such an ornament and its evolution as well as its specificity and various functions within the narration. This study also aims at defining the influence of the socio-cultural context (wordliness) upon the epistolary writing in novels and the relation between letters as found in novels and novels made of letters. Although the study focuses mainly upon the works of mademoiselle de scudery, it also draws upon earlier or contemporary writings including l'astree by honore d'urfe
Viguetti, Sarah Carolina Zanetti e. "Epidemiologia molecular de linhagens invasivas de Corynebacterium diphtheriae utilizando o método MLST." Universidade Federal de Minas Gerais, 2010. http://hdl.handle.net/1843/BUOS-8W2JKK.
Full textA difteria é considerada por várias agências de saúde internacionais como uma doença re-emergente. A forma clássica da doença, causada pela bactéria Corynebacterium diphtheriae, afeta primariamente o trato respiratório superior. No entanto, existem alguns isolados desta bactéria capazes de causar infecções invasivas, como endocardite. No Brasil, linhagens de C. diphtheriae causadoras deste tipo de infecção têm sido isoladas nos últimos anos. Estas linhagens foram capazes de infectar pessoas vacinadas com o toxóide diftérico (DT) e suas principais características distintivas foram, na maioria dos casos, a capacidade de fermentar sacarose e o perfil não-toxigênico. A escassez de infromações sobre os mecanismos que levam ao fenótipo invasivo evidencia a necessidade de estudos genéticos desta sub-população de C. diphtheriae. O objetivo do presente estudo foi realizar uma análise epidemiológica molecular destas linhagens invasivas brasileiras, utilizando a técnica de Multilocus Sequence Typing (MLST). Um esquema de MLST padronizado para tipagem de C. diphtheriae foi utilizado, composto por sete genes housekeeping desta bactéria: atpA, dnaE, dnaK, fusA, leuA, odha, e rpoB. Como controles, foram tipadas linhagens padrão de C. diphtheriae. Os resultados obtidos foram comparados com perfis de MLST de grupos clonais de C. diphtheriae isolados em diferentes países, os quais estão depositados no banco de dados PubMLST. Os perfis obtidos para as linhagens invasivas foram divididos em três complexos clonais pelo programa eBURST. As linhagens foram consideradas como sendo de um mesmo complexo clonal quando pelo menos seis dos sete alelos estudados no MLST eram compartilhados. As linhagens brasileiras do biotipo gravis agruparam-se em complexos clonais com cepas originárias da Europa, indicando uma circulação mundial dos clones deste biotipo e alta estabilidade genética. Por outro lado, linhagens invasivas do biotipo mitis apresentaram maior diversidade genética e uma circulação aparentemente associada à América do Sul. As análises realizadas sugerem que a alta diversidade genética encontrada para as linhagens invasivas é devida a um elevado potencial recombinogênico dos isolados.
Silva, Givago Faria Ribeiro da. "Caracterização fenotípica e molecular de estirpes de Haemophilus parasuis isoladas de suínos da região Centro-sul do Brasil." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/10/10134/tde-21062016-124945/.
Full textHaemophilus parasuis is the etiological agent of Glässer disease that causes arthritis, pneumonia, meningitis and polyserositis in pigs and has assumed great importance in modern swine production, since its occurrence has increased significantly in recent years in herds affected by porcine circovirus type 2. In the present study 117 strains of H. parasuis isolated between 2009 to 2014 were utilized, isolated from pigs of south center of Brazil. The strains were serotyping, confirmed genus/species by PCR, the antimicrobial resistance profile was evaluated determining the minimum inhibitory concentration (MIC) and strains were genotypically characterized by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and presence of vtA virulence gene. The major serotypes identified were 4 (21.3%), 5 (12.9%), 13 (9.4%), 14 (7.7%) and at last the 1 (1.7%), In some cases more than one serotype was identified in the same farm and in the same animal, this results were identified in others parts of the world. All samples had vtA gene. The resistance for some antibiotics was high for tylosin (98.29%), danofloxacin (95.72%) sulfadimetoxin (88.03%), and penicillin (77.7%). Multidrug resistance rates reached 93.16% of the samples. A total of 67 different profiles were identified in PFGE and nine samples were analyzed by MLST. All nine strains tested were identified as new STs. When these strains were compared with MLST database, they were dispersed among the strains from other countries. In this study, it was clear that the Brazilian H. parasuis strains are highly variable considering serotypes, resistance profiles, genomic analysis of PFGE and MLST
Adams, Coy M. "VoIP quality measurements in a Multilevel Secure (MLS) environment." Thesis, Monterey, Calif. : Naval Postgraduate School, 2008. http://bosun.nps.edu/uhtbin/hyperion-image.exe/08Mar%5FAdams.pdf.
Full textThesis Advisor(s): Irvine, Cynthia E. ; Irvine, Nelson J. "March 2008." Description based on title screen as viewed on April 25, 2008. . Includes bibliographical references (p. 113). Also available in print.
Murphy, Timothy A. "MLS Flight inspection techniques: Digital filtering and coordinate transformation." Ohio : Ohio University, 1985. http://www.ohiolink.edu/etd/view.cgi?ohiou1184070645.
Full textAlpert, Stephanie. "Novel Use of Scenarios in the Usability Engineering of a Next-generation MLST Tool." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/47452.
Full textMaster of Science
Sontowski, Rebekka, Detlef Bernhard, Christoph Bleidorn, Martin Schlegel, and Michael Gerth. "Wolbachia distribution in selected beetle taxa characterized by PCR screens and MLST data." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-185242.
Full textGoldbeck, Justina. "What is MLE, who speaks it, and is it safe?" Scholarship @ Claremont, 2018. http://scholarship.claremont.edu/scripps_theses/1172.
Full textTrunzler, Jean. "Contribution à l'enrichessement des fonctions d'approximation sans maillage RKPA / MLS." Paris, ENSAM, 2005. http://www.theses.fr/2005ENAM0034.
Full textNowadays, the engineering of design and manufacture requires more and more the use of tools for numerical simulation. The majority of the Current industrial codes use the finite element method. That presents a certain number of limitations for the simulation of large strains, localization problems. . . The need to construct a mesh satisfying quality criteria implies an important investment on behalf of the user. To eliminate this type of constraints, we directed ourselves towards the meshfree methods, the approximation function is built starting from a cloud of nodes distributed on the field of study. The first part presents a comparative study of the approximation functions of the type RKP A and MLS. In the second part, we present a technique of enrichment of functions RKP A. The basic concept comes from functions MLS; it is a question of introducing into the base of reproduction every functions which one wishes to reproduce. This technique is applied to the treatment of problems presenting a fixed or mobile hardware interface (Stefan problem). The last part treats of the incompressible Stokes problem. We present various strategies to stabilize the field of pressure. The various problems dealt with in this study were solved by collocation methods. Our interest was to use a method which does not require integration or which reduces the costs of numerical integration significantly
Santos, Sílvia Regina dos. "Determinação de sorotipos capsulares de Streptococcus pneumoniae por Multiplex-PCR sequencial." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-12092012-100134/.
Full textS.pneumoniae colonizes the nasopharynx and is a major agent of otitis media, pneumonia, bacteremia and meningitis with high morbidity and mortality. It is estimated that 1.6 million people die of pneumococcal disease every year, mostly children under five years old, mainly in developing countries. The antiphagocytic polissarídica capsule is the main virulence factor of this organism and determine the 93 serotypes known for being the target of pneumococcal vaccines. In the present study was standardized molecular typing by Multiplex PCR molecular typing, which comprises 30 primer pairs grouped into six sequential reactions. We performed antimicrobial susceptibility profile, according to the CLSI 2011 and the most frequent serotype was made by molecular genotyping techniques Multilocus Sequence Typing (MLST) and pulsed-field gel Eletrophoresis (PFGE). We studied 270 pneumococcal strains isolated from 2005 to September 2011, from CSF (13%), blood (76%) and pleural fluid (11%) of 232 patients attended at University Hospital of USP. Typing by Multiplex PCR detected 24 serotypes / serogroups different, which were: 14 (22%), 5 (12%), 12F / A (11%), 6A/B/C (10%), 7F / A (5 %), 1 (4%), 3 (4%), 10A (4%), 19A (4%), 18 A / B / C / F (3%), 4 (3%), 8 (3% ), 23F (3%), 19F (3%) and others (9%) (9V / A, 9N / L, 15A, 22F, 11A / D, 31, 38, 34, 16F, 17F and nontypable). This method showed 100% specificity and 98% sensitivity for the determination of 66% for serogroups and serotypes. Serotypes significantly more common in children under two years were: 14, 6B, 5 and 19F among adults serotypes 5 e12F were predominant. The sensitivity profile in non-meningeal infections was 99% sensitivity and 1% penicillin intermediate resistance to ceftriaxone. For meningeal infections the results showed 73% sensitivity and 27% resistance to penicillin and 88% sensitivity and 12% intermediate resistance to ceftriaxone. Resistance to beta-lactams is linked mainly to serotype 14 was the serotype most isolated, and of these 52 strains were performed MLST and PFGE. MLST found in 51 strains belonging to clone Spain9V-3 (ST 156) which is prevalent in south and southeastern Brazil and a strain with a type of sequence is not deposited. The technique of PFGE found three clusters and four non-related samples, cluster A predominated with 41 (79%) strains with 81.7% similarity between them. Multiplex PCR technique proved to be an excellent tool for the detection of serotypes/serogroups of S. pneumoniae. We did not detect full resistance to penicillin and ceftriaxone in non-meningeal infections showing the importance of use of penicillin in the treatment of pneumococcal non-meningeal disease. There was great genetic similarity among strains of S. pneumoniae serotype 14.
Possebon, Fábio Sossai. "Perfil molecular e resistência a antimicrobianos de Salmonella isolada em linfonodos mesentéricos de suínos." Botucatu, 2016. http://hdl.handle.net/11449/134337.
Full textResumo: O presente trabalho avaliou 250 animais de 25 lotes distintos abatidos em 4 estabelecimentos do estado de São Paulo para a presença de Salmonella nos linfonodos mesentéricos, e caracterizou o perfil de resistência das cepas isoladas aos principais antibióticos. O patógeno estava presente em 36,4% das amostras e 72% dos lotes analisados. Dos 91 isolados, 67 foram sorotipados, e os principais sorovares encontrados foram S. Typhimurium (n=13), S. 1.4,5,12:i:- (n=12) S. Infantis (n=12) e S. Havana (n=11). Os compostos com menor eficácia frente aos isolados foram estreptomicina e tetraciclina (68,1% de resistência) ampicilina e sulfonamidas (62,6%), cloranfenicol (56,0%), trimetoprim-sulfametoxazol (41,8%) e ácido nalidíxico (40,7%). Os mais efetivos foram aztreonam e cefoxitina, (ambos com 3,3% de resistência) e cefepima e ceftriaxona, (ambos com 7,7%). Cepas multidrogas resistentes (MDR) corresponderam a 70,3% dos isolados. Oito cepas foram submetidas ao MLST: quatro S. Typhimurium e uma S. 1.4,5,12:i:- todas pertencentes ao ST 19, duas S. Infantis pertenceram ao ST 32 e uma S. Derby, pertencente ao ST 40. A grande prevalência do patógeno nos animais analisados, com altas taxas de resistência aos antibióticos e pertencentes a grupos genéticos frequentemente associados a surtos e doenças em humanos demonstram que a cadeia produtiva da carne suína é uma fonte de contaminação em potencial nos casos de salmonelose, sendo necessárias medidas preventivas eficazes para o controle do pa... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This study evaluated 250 animals of 25 different batches processed in four slaughterhouses in São Paulo state - Brazil for the presence of Salmonella in the mesenteric lymph nodes, and characterized the resistance profile for the main antibiotics. The pathogen was present in 36.4% of samples and 72% of the analyzed batches. Of the 91 isolates, 67 were serotyped, and the main serovars found were S. Typhimurium (n = 13), S. 1.4,5,12:i- (n = 12) S. Infantis (n = 12) and S. Havana (n = 11). The compounds with less efficacy were streptomycin and tetracycline (68.1% resistant) ampicillin and sulphonamides (62.6%), chloramphenicol (56.0%), trimethoprim-sulfamethoxazole (41.8%), and nalidixic acid (40.7%). The most effective were cephalothin and aztreonam, (both with 3.3% resistant) and ceftriaxone and cefepime (both with 7.7%). Multidrug-resistant strains (MDR) accounted for 70.3% of the isolates. Eight strains were submitted to MLST: Four S. Typhimurium and one S.1.4,5,12:i:- all belonging to the ST 19, two S. Infantis, belonging to the ST 32 and one S. Derby, belonging to ST 40. The high prevalence of the pathogen in the analyzed animals, with high rates of resistance to antibiotics and belonging to genetic groups that are often associated with outbreaks and disease in humans, shows that the production chain of pork is a potential source of contamination in salmonellosis cases, with the necessity of effective preventive measures for pathogen control and lower the risk of foodborne... (Complete abstract click electronic access below)
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Ménard, Isabelle. "Une nouvelle méthode d'épidémiologie moléculaire pour le chlamydia trachomatis le multi locus sequence typing." Mémoire, Université de Sherbrooke, 2011. http://hdl.handle.net/11143/5557.
Full textPossebon, Fábio Sossai [UNESP]. "Perfil molecular e resistência a antimicrobianos de Salmonella isolada em linfonodos mesentéricos de suínos." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/134337.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O presente trabalho avaliou 250 animais de 25 lotes distintos abatidos em 4 estabelecimentos do estado de São Paulo para a presença de Salmonella nos linfonodos mesentéricos, e caracterizou o perfil de resistência das cepas isoladas aos principais antibióticos. O patógeno estava presente em 36,4% das amostras e 72% dos lotes analisados. Dos 91 isolados, 67 foram sorotipados, e os principais sorovares encontrados foram S. Typhimurium (n=13), S. 1.4,5,12:i:- (n=12) S. Infantis (n=12) e S. Havana (n=11). Os compostos com menor eficácia frente aos isolados foram estreptomicina e tetraciclina (68,1% de resistência) ampicilina e sulfonamidas (62,6%), cloranfenicol (56,0%), trimetoprim-sulfametoxazol (41,8%) e ácido nalidíxico (40,7%). Os mais efetivos foram aztreonam e cefoxitina, (ambos com 3,3% de resistência) e cefepima e ceftriaxona, (ambos com 7,7%). Cepas multidrogas resistentes (MDR) corresponderam a 70,3% dos isolados. Oito cepas foram submetidas ao MLST: quatro S. Typhimurium e uma S. 1.4,5,12:i:- todas pertencentes ao ST 19, duas S. Infantis pertenceram ao ST 32 e uma S. Derby, pertencente ao ST 40. A grande prevalência do patógeno nos animais analisados, com altas taxas de resistência aos antibióticos e pertencentes a grupos genéticos frequentemente associados a surtos e doenças em humanos demonstram que a cadeia produtiva da carne suína é uma fonte de contaminação em potencial nos casos de salmonelose, sendo necessárias medidas preventivas eficazes para o controle do patógeno e diminuição do risco de veiculação de patógenos por alimentos.
This study evaluated 250 animals of 25 different batches processed in four slaughterhouses in São Paulo state - Brazil for the presence of Salmonella in the mesenteric lymph nodes, and characterized the resistance profile for the main antibiotics. The pathogen was present in 36.4% of samples and 72% of the analyzed batches. Of the 91 isolates, 67 were serotyped, and the main serovars found were S. Typhimurium (n = 13), S. 1.4,5,12:i- (n = 12) S. Infantis (n = 12) and S. Havana (n = 11). The compounds with less efficacy were streptomycin and tetracycline (68.1% resistant) ampicillin and sulphonamides (62.6%), chloramphenicol (56.0%), trimethoprim-sulfamethoxazole (41.8%), and nalidixic acid (40.7%). The most effective were cephalothin and aztreonam, (both with 3.3% resistant) and ceftriaxone and cefepime (both with 7.7%). Multidrug-resistant strains (MDR) accounted for 70.3% of the isolates. Eight strains were submitted to MLST: Four S. Typhimurium and one S.1.4,5,12:i:- all belonging to the ST 19, two S. Infantis, belonging to the ST 32 and one S. Derby, belonging to ST 40. The high prevalence of the pathogen in the analyzed animals, with high rates of resistance to antibiotics and belonging to genetic groups that are often associated with outbreaks and disease in humans, shows that the production chain of pork is a potential source of contamination in salmonellosis cases, with the necessity of effective preventive measures for pathogen control and lower the risk of foodborne diseases transmission.
Armand-Lefèvre, Laurence. "Influence de l'environnement sur le portage nasal et la diversité de Staphylococcus aureus sensible et résistant à la méticilline." Paris 11, 2009. http://www.theses.fr/2009PA114808.
Full textStaphylococcus aureus is one of the most important pathogen in human infection diseases. S. Aureus is also a bacteria present in commensal flora of about a quarter of the population. For years, S. Aureus has acquired antibiotic resistances traits of various clinical relevance, of which methicillin resistance might be the most important. Methicillin-resistant S. Aureus (MRSA) is the first multiresistant bacteria isolated in hospitalised patients. The studies presented in this PhD Thesis analysed the nasal carriage of methicillin-susceptible or resistant S. Aureus in different populations exposed to contrasted environments : professional (pig farmers, nursing students) or hospital (hospitalized patients). The genetic diversity of strains circulating in these environments was also investigated
He, Wenmin. "Cooperative Channel State Information Dissemination Schemes in Wireless Ad-hoc Networks." Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-theses/288.
Full textSilva, Leila Priscilla Pinheiro da. "Epidemiologia molecular e genética da resistência à vancomicina em enterococos isolados de pacientes de dois hospitais de Ribeirão Preto." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/60/60135/tde-08102012-111127/.
Full textWorld reports on vancomycin resistance emerged in the late 1980s and first documented in Western Europe and later in the United States. Since then, isolation of vancomycin-resistant enterococci (VRE) has been continuously reported in several geographic locations, including Brazil. The widespread occurrence of strains resistant to multiple antibiotics present a challenge to clinicians when treating enterococci caused nosocomial infections. Several molecular typing methods have been used to study the epidemiology of VRE. In this study, genetic characterization of vancomycin resistance and molecular epidemiology were performed in VREs isolated from patients in two hospitals in Ribeirão Preto, Sao Paulo/Brazil, the University Hospital of the Faculty of Medicine of Ribeirao Preto, University of Sao Paulo (HCFMRP-USP) and the Santa Casa de Misericórdia de Ribeirão Preto (SCMRP), from September 2008 to September 2010. The first five VREs isolated in the HCFMRP-USP, in mid 2005/2006 were also included in this study. Species and genotypes of 53 VREs determined by the polymerase chain reaction (PCR) were all E. faecium and had the vanA gene. MICs for vancomycin determined by Etest® were >256?g/mL for all E. faecium isolated in the two hospitals, whereas daptomycin showed MIC values within the limit of susceptibility for all the enterococci analyzed. acm and esp genes predominated as virulence factors. The first five vancomycin resistant E. faecium (VREfm) isolated in mid 2005/2006 showed an intact Tn1546 transposon, whereas all E. faecium isolated later, September 2008 to September 2010, gave a larger amplified DNA fragment than the expected 4,4kb gene cluster vanRSHAX. Results of overlapping PCR and sequencing (primers P11-P12) of the transposon region that amplified the larger than expected DNA fragment showed that 81% (n=43) of the these VREfm had a deletion of the left end of Tn1546 and also a IS1251, between the vanS and vanH genes. The analysis of VREfm PFGEs indicated the occurrence of clonal disseminations with some PFGE profiles at specific times. The different PFGE profiles of the first VREfm (2005-2006) in relation to the latter isolates showed that the common ancestor could not be determined by PFGE. However, MLST results indicated that VREfm isolated, in the period from 2008 to 2010, could be direct descendants of the first five VREfm or could have evolved from a common ancestor. MLST analysis of 31 VREfm isolates selected according to the PFGE results, showed that there were nine different STs, among these five new STs (656, 657, 658, 659, 660). The predominant STs were ST412 and 478. All STs identified belonged to clonal complex 17 (CC17), except for ST658, a singleton. The ST78 that has spread worldwide is being identified in Brazil for first time in this study. MLST confirmed PFGE results showing that there is a clonal link between strains isolated in the two hospitals of Ribeirao Preto, Sao Paulo, Brazil.
Dasananda, Songkot. "Capability of MLS instruments in the observations of atmospheric gravity waves." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/13569.
Full textBridier, Julen. "Etude de la diversité intraspécifique de l’espèce Oenococcus oeni, relation entre variabilité phénotypique et diversité génétique." Thesis, Bordeaux 2, 2011. http://www.theses.fr/2011BOR21881/document.
Full textOenococcus oeni is the main agent responsible for the malolactic fermentation, during the wine making process. Its adaptation to wine environment is a key step for the success of the MLF, and then for wines quality. However, there is a high phenotypic variability among the species and several strains are unable to perform MLF. The selection of the best enological strains implies starting by analyzing the diversity of O. oeni. This study has been divided in three main themes of research. Firstly, the genetic diversity has been analyzed using several approaches, MLST, REA-PFGE and presence of genetic markers. That study proved the structuration of the species in two phylogenetic groups and several subgroups, related to geographical areas. Secondly, the study of the phenotypic diversity showed that all the studied strains present a high variability and the best behavior in wine making conditions is found in those from the phylogenetic group A. Finally, a transcriptional analysis has revealed some molecular mechanisms possibly implicated in stress response in O. oeni
Hippler, Corinna. "Molekularepidemiologische Untersuchung von klinischen Acinetobacter baumannii und Acinetobacter Genospezies 13TU mittels Multilocus Sequenz Typisierung (MLST) /." Köln, 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000253632.
Full textHelene, Luisa Caroline Ferraz. "Diversidade entre estirpes do gênero Bradyrhizobium avaliada por Multilocus Sequence Analysis (MLSA) e análise polifásica." Universidade Estadual de Londrina. Centro de Ciências Biológicas. Programa de Pós-Graduação em Microbiologia, 2015. http://www.bibliotecadigital.uel.br/document/?code=vtls000201471.
Full textSymbiotic nitrogen-fixing bacteria, also commonly called rhizobia, have great agronomic relevance because they can provide significant amounts of nitrogen to plants and help in the recovery of soils and degraded environments. In recent years, with the advances in molecular techniques, several studies have shown that these bacteria have a high level of genetic diversity, resulting in taxonomic reclassifications and description of new species. Although the 16S ribosomal genes (16S rRNA) are still used in phylogenetic analyses of prokaryotes, their high conservation do not allow to reveal differences between species of several genera, including Bradyrhizobium. Other methodologies such as the MLSA (Multilocus Sequence Analysis) are being used to elucidate these cases, with good results. In this study, 15 strains of Bradyrhizobium without clear taxonomic position were used in studies of phylogeny and taxonomy based on the MLSA technique. Tree housekeeping genes?glnII, gyrB and recA?were sequenced and their sequences were concatenated and used for the construction of a phylogenetic tree. Of the 15 strains, seven grouped with the species Bradyrhizobium pachyrhizi, while the SEMIAS 6159, 6405 and 6408 strains occupied isolated locations, and two groups (SEMIAS 6399 and 6404, and SEMIAS 690, 6387 and 6428) showed no genetic similarity with any described species. These groups deserve more detailed studies, since they have great potential to represent new species. Strains SEMIA 690 (isolated from Centrosema pubescens), SEMIA 6387 and SEMIA 6428, (isolated from Acacia spp.) were selected for a polyphasic study (genetic, phenotypic and phylogenetic analyzes) aimed at the description of a new species. The BOX-PCR profile clustered the strains with more than 73% of similarity, and less than 66% with closer Bradyrhizobium described species. Fatty acids identified as key in SEMIA 690 were summed features 8 and individual fraction C19:0 cycle ?8c. The genomic analysis of ANI (average nucleotide identity) between SEMIA 690 and closer type strains of Bradyrhizobium species was less than 91%. The G + C content from SEMIA 690 was of 63.46%. The phenotypic tests (carbon sources used, morphological characteristics, growth conditions) were congruent among the strains representative of the new putative species. The results confirm that the MLSA technique is efficient for phylogenetic studies of prokaryotes, representing a reliable and fast tool to analyze the diversity of genes and to identify possible new rhizobial species. The results obtained in this study also support the description of a new species of Bradyrhizobium.
Petzold, Markus. "Array hybridization and whole genome sequencing as new typing tools for Legionella pneumophila." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-233546.
Full textCosta, Natália Silva da. "Análise do polimorfismo numérico de sequências repetitivas em múltiplos loci (MLVA) como instrumentos de avaliação da diversidade genética de Streptococcus pneumoniae do sorotipo 14." Universidade do Estado do Rio de Janeiro, 2012. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=6065.
Full textStreptococcus pneumoniae é um importante agente etiológico de infecções invasivas e não invasivas, incluindo meningite, pneumonia e otite média. A cápsula polissacarídica é o principal fator de virulência desse microrganismo, sendo também considerada um importante marcador em estudos epidemiológicos. Dentre os mais de 90 tipos capsulares conhecidos, o sorotipo 14 se destaca pela prevalência elevada em várias regiões, inclusive no Brasil. A avaliação da diversidade genética desse microrganismo também inclui a aplicação de métodos moleculares, como PFGE e MLST. Entretanto, essas metodologias são relativamente onerosas, consomem muito tempo e os resultados obtidos com a técnica de PFGE são de difícil comparação entre diferentes laboratórios. A técnica de análise do polimorfismo numérico de segmentos repetitivos em múltiplos loci [MLVA, do inglês Multiple Loci VTNR (Variable-Number Tandem Repeat) Analysis] se apresenta como uma alternativa, embora ainda necessite de padronização e avaliação mais ampla para a espécie em questão. No presente estudo, 60 amostras de Streptococcus pneumoniae pertencentes ao sorotipo 14, isoladas de diversas fontes clínicas, em diferentes locais e períodos de tempo, foram caracterizadas pelas técnicas de MLVA (baseada na análise de 18 loci distintos), MLST, PFGE e tipagem do gene pspA. O gene pspA2 predominou entre as amostras analisadas, seguido pelo gene pspA1. Os tipos de MLVA, perfis de PFGE, e STs encontrados apresentaram resultados, em geral, concordantes, indicando o elevado poder discriminatório da versão da técnica de MLVA empregada. Cinco complexos clonais (CC) de MLVA e cinco singletons puderam ser definidos. O CC de MLVA denominado de L7 foi o predominante, compreendendo 36,7% da amostragem estudada. O CC L7 mostrou-se relacionado com genes pspA da família 2, com o CC1 de MLST, com o CC Pen14-H de PFGE, e com a não susceptibilidade à penicilina, Entre os complexos clonais de MLST, o CC1 foi o prevalente e incluiu predominantemente o ST156, pertencente ao clone internacional Spain9V-3. O CC L3 e o singleton L17 de MLVA apresentaram-se associados ao CC de PFGE Eri14-A, a família 1 de PspA e ao CC2 de MLST, que por sua vez também estava relacionado com o clone internacional England14-9. O CC L15 de MLVA esteve associado ao CC de PFGE Pen14-A, ao gene pspA2, aos CC3 e CC4 de MLST e ao clone internacional do PMEN Tennessee14-18. A técnica de MLVA revelou-se significativamente mais discriminatória que as técnicas de PFGE e MLST, conforme exemplificado pela detecção de 21 perfis de MLVA, 13 perfis de PFGE e cinco STs, entre as 22 amostras pertencentes ao CC de MLVA L7. Uma versão de MLVA, compreendendo um painel com os oito loci de maior poder discriminatório, pôde ser proposta a partir da análise dos resultados obtidos. Estes aspectos, aliados ao menor tempo e custo de execução, indicam que a técnica de MLVA constitui uma alternativa importante e satisfatória para uso em estudos sobre a diversidade genética de S. pneumoniae.
Streptococcus pneumoniae is a major pathogen causing invasive and non-invasive diseases in humans, including meningitis, pneumonia and otitis media. The polysaccharide capsule of this microorganism is considered a major virulence factor and an important marker for epidemiological studies. More than 90 pneumococcal capsular serotypes are recognized, and serotype 14 is highly prevalent in many regions, including Brazil. Genotyping methods, such as PFGE and MLST, are essential to evaluate genetic diversity of this bacterium. However, these methods are expensive, time-consuming and results from different laboratories are difficult to compare. Multiple Loci VTNR (Variable-Number Tandem Repeat) Analysis (MLVA) appears as an alternative, despite the fact that standardization and wide evaluation for application to this species is still required. In the present study, a total of 60 S. pneumoniae isolates belonging to serotype 14, isolated from different sources, regions and periods of time, were analyzed by MLVA (based on the analysis of 18 distinct loci), MLST, PFGE and pspA typing methods. Gene pspA2 was the predominant, followed by pspA1. Overall, the results of PFGE, MLST and MLVA typing were congruent, and indicated the discriminatory power of the MLVA method used. Five clonal complexes (CC) and five singletons were identified by MLVA. CC L7 was the predominant MLVA CC, comprising 36.7% of all the isolates. L7 was associated with pspA2 gene and non-susceptibility to penicillin, and it was related to MLST CC1, and to PFGE Pen14-H. CC1 was the prevalent MLST CC and included mostly ST156 that belongs to international clone (IC) Spain9V-3. Another MLVA CC, named L3, and the singleton L17 were related to PFGE CC Eri14-A, MLST CC2, and IC England14-9. MLVA CC L15 was related to PFGE Pen14-A, MLST CC3 and CC4, and IC Tennessee14-18. MLVA was found to be more discriminatory than PFGE and MLST, as exemplified by detection of 21 MLVA types, 13 PFGE profiles and 5 STs among the 22 strains belonging to L7, the predominant MLVA CC. A modified version of the MLVA method, based on the analysis of 8 loci only, is proposed. This aspect, in conjunction with reducing time and costs, indicate that MLVA represents an important and satisfactory alternative method to evaluate the genetic diversity of S. pneumoniae.
Rogers, Thomas John. "Design models for multimedia learning environments based on interactive drama." Thesis, University of Plymouth, 2000. http://hdl.handle.net/10026.1/341.
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