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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Growth and Biofilm Formation by Staphylococcus Epidermidis and Other Relevant Contaminant Bacteria During Storage of Platelet Concentrates

Greco, Carey Anne 28 September 2011 (has links)
Coagulase negative staphylococci (CoNS) are the most prevalent bacterial contaminants of platelet concentrates (PCs), and have been implicated in severe and fatal transfusion reactions. Of this group, Staphylococcus epidermidis is most frequently identified. The preliminary objective of this thesis was to confirm that S. epidermidis could form biofilms under platelet storage conditions. This was achieved using a modified crystal violet staining assay to detect plastic-adherent bacterial cells and examination of attachment processes by scanning electron microscopy. A collection of CoNS isolated from PCs obtained from reportedly healthy donors was then assessed for biofilm-forming potential at the genetic and phenotypic level. Despite the presumable commensal origin of these isolates, a high proportion of S. epidermidis strains displayed a biofilm positive phenotype. The threat of S. epidermidis biofilm formation during platelet storage identified herein signifies that any alterations made to platelet storage protocols should be evaluated with consideration of this risk. The advent of platelet additive solutions (PASs) as an alternative to plasma for PC storage provides a relevant example, since little is known about the effect of PAS on contaminant bacteria, and vice versa. Growth and biofilm formation by S. epidermidis and the Gram-negative bacterium Serratia liquefaciens were measured in PAS- or plasma-PCs over 5 days, simulating standard platelet storage conditions, after initial inoculation with low, clinically relevant bacterial concentrations. Assays for platelet quality were performed simultaneously. Only S. liquefaciens exhibited a slower doubling time in plasma-PCs than in PAS-PCs. Biofilm formation by both species was reduced during storage in PAS-PCs, increasing bacteria availability for detection. Although S. liquefaciens adversely affected platelet quality in both media, S. epidermidis contamination did not. Ultimately, culture-based detection remains the earliest indicator of bacterial presence in PAS-PCs. Lastly, since formation of platelet-bacteria aggregates is largely based on receptor-ligand interactions, it was postulated that biofilm formation by contaminant bacteria could be abrogated by receptor shielding. Methoxypoly(ethylene glycol) was applied to covalently modify the platelet surface using a process termed ‘PEGylation’. It is herein demonstrated that PEGylation of PCs inoculated with S. epidermidis results in significantly reduced bacterial binding and biofilm formation during platelet storage.
82

Coagulase-negative staphylococci septicaemia in newborns : aspects on host-bacterial interactions with special regard to neutrophil and endothelial response /

Björkqvist, Maria, January 2004 (has links) (PDF)
Diss. (sammanfattning) Linköping : Univ., 2004. / Härtill 4 uppsatser.
83

Genes para enterotoxinas em Staphylococcus sp. isolados de manipuladores de alimentos de um restaurante universit?rio na cidade do Natal-RN

Silva, Sabina dos Santos Paulino da 24 September 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-09-06T20:18:32Z No. of bitstreams: 1 SabinaDosSantosPaulinoDaSilva_DISSERT.pdf: 971170 bytes, checksum: de3fd16a5be3f838661b201aef9e1cbc (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-09-06T23:23:48Z (GMT) No. of bitstreams: 1 SabinaDosSantosPaulinoDaSilva_DISSERT.pdf: 971170 bytes, checksum: de3fd16a5be3f838661b201aef9e1cbc (MD5) / Made available in DSpace on 2016-09-06T23:23:48Z (GMT). No. of bitstreams: 1 SabinaDosSantosPaulinoDaSilva_DISSERT.pdf: 971170 bytes, checksum: de3fd16a5be3f838661b201aef9e1cbc (MD5) Previous issue date: 2015-09-24 / Os manipuladores de alimentos colonizados por Staphylococcus produtores de enterotoxinas s?o uma fonte potencial de intoxica??o alimentar. O objetivo deste estudo foi pesquisar a presen?a de genes que codificam enterotoxinas em Estafilococos Coagulase Positivos (ECP) e Estafilococos Coagulase Negativos (ECN) isolados das narinas e das m?os dos manipuladores de alimentos de um restaurante universit?rio na cidade de Natal-RN. Trinta manipuladores de alimentos foram inclu?dos no estudo. O material das m?os e das narinas foi coletado utilizando um swab est?ril. Os isolados foram submetidos ? colora??o de Gram, teste de sensibilidade a bacitracina, fermenta??o de manitol e provas para a catalase e coagulase livre. Os ECNs e ECPs foram posteriormente identificados atrav?s de testes bioqu?micos e pelo sistema Vitek 2 (BioMerieux, Fran?a). A t?cnica da rea??o em cadeia da polimerase (PCR) foi utilizada para a detec??o dos genes para as enterotoxinas A, B, C, D, E, G, H, e I (sea, seb, sec, sed, see, seg, seh, e sei) e o m?todo de disco-difus?o foi utilizado para a determina??o da susceptibilidade aos antimicrobianos. Todos os manipuladores de alimentos apresentaram Estafilococos em suas m?os e/ou narinas. Foram isolados 58 Staphylococcus sp., dos quais 20,7% eram ECP e 79,3% eram ECN. Staphylococcus epidermidis foi a esp?cie mais prevalente. Vinte e nove Estafilococos (50%) apresentaram um ou mais genes para enterotoxinas e os genes mais prevalentes foram seg e sei, com uma frequ?ncia de 29,3% para ambos. Dentre as cepas de Staphylococcus aureus, 75% possu?am genes para enterotoxinas. Entretanto, os ECNs apresentaram uma frequ?ncia elevada de genes (43,5%). A maioria dos isolados mostrou sensibilidade aos antibi?ticos testados, com exce??o da penicilina para a qual apenas 35% das cepas foram sens?veis. Os resultados deste estudo mostram que n?o somente os Estafilococos coagulase positivos, mas tamb?m os coagulase negativos s?o portadores de genes para enterotoxinas. / Food handlers carrying enterotoxin-producing Staphylococcus are a potential source of food contamination. The aim of this study was to analyze genes enconding enterotoxins in coagulase-positive Staphylococcus (CoPS) and coagulase-negative Staphylococcus (CoNS) isolated from the anterior nostrils and hands of food handlers at a university restaurant in the city of Natal, Northeast Brazil. Thirty food handlers were screened for the study and the collected Staphylococcus sp. Most isolates were subjected to Gram staining, a bacitracin sensitivity test, mannitol fermentation, and catalase and coagulase tests. CoNS and CoPS strains were subsequently identified by biochemical tests and a Vitek 2 System (BioMerieux, France). PCR was used to detect genes for enterotoxins A, B, C, D, E, G, H, and I (sea, seb, sec, sed, see, seg, seh, and sei) and a disc-diffusion method was used to determine susceptibility to several classes of antimicrobials. All food handlers presented staphylococci on their hands and/or noses. The study found 58 Staphylococcus sp., of which 20.7% were CoPS and 79.3% were CoNS. Staphylococcus epidermidis was the most prevalent species. Fifty percent of Staphylococcus spp. isolated was positive for one or more enterotoxin genes, and the most prevalent genes were seg and sei, each with a frequency of 29.3%. Indeed, CoNS encoded high percentage of enterotoxin genes (43.5%). However, Staphylococcus aureus encoded even more enterotoxin genes (75%). Most isolates showed sensitivity to the antibiotics used for testing, except for penicillin (only 35% sensitive). The results from this study reinforce that coagulase-negative as well as coagulase-positive staphylococci isolated from food handler are capable of genotypic enterotoxigenicity.
84

Resist?ncia ? linezolida em estafilococos coagulase negativos resistentes ? meticilina provenientes de hospitais da cidade de Natal-RN

Cidral, Thiago Andr? 15 January 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-09-06T20:24:13Z No. of bitstreams: 1 ThiagoAndreCidral_DISSERT.pdf: 3578139 bytes, checksum: bcb8c85feab01e028e946691a0776a04 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-09-06T23:31:16Z (GMT) No. of bitstreams: 1 ThiagoAndreCidral_DISSERT.pdf: 3578139 bytes, checksum: bcb8c85feab01e028e946691a0776a04 (MD5) / Made available in DSpace on 2016-09-06T23:31:16Z (GMT). No. of bitstreams: 1 ThiagoAndreCidral_DISSERT.pdf: 3578139 bytes, checksum: bcb8c85feab01e028e946691a0776a04 (MD5) Previous issue date: 2016-01-15 / Os Estafilococos Coagulase Negativos (ECN) s?o microrganismos pertencentes ? microbiota normal da pele e de mucosas dos seres humanos e de animais. A maioria das infec??es causadas por ECN est?o relacionadas ao uso de dispositivos m?dicos invasivos que ao lesionar a integridade da pele servem de base para a forma??o de biofilmes, um importante fator de virul?ncia. Grande parte dos isolados de coagulase negativo s?o provenientes de hemoculturas e pontas de cateter e nos ?ltimos anos vem se tornando um grave problema no que diz respeito ? antibioticoterapia, em virtude do n?mero elevado de cepas multirresistentes descritas. O objetivo deste trabalho foi pesquisar resist?ncia ? linezolida em estafilococos coagulase negativos resistentes ? meticilina isolados de ponta de cateter e hemocultura de hospitais p?blicos e privados da cidade do Natal. Os isolados bacterianos foram coletados a partir de demanda espont?nea em Hospitais P?blicos e Privados. O g?nero Staphylococcus foi confirmado atrav?s dos testes de rotina como colora??o de Gram, prova da catalase da coagulase livre. A identifica??o a n?vel de esp?cie foi realizada atrav?s de testes bioqu?micos convencionais. Algumas amostras tiveram sua identifica??o confirmada pelos sistemas VITEK 2 e MALDI-TOF. O perfil de resist?ncia aos antimicrobianos foi avaliado atrav?s da t?cnica de disco-difus?o (CLSI 2013). A Concentra??o Inibit?ria M?nima para vancomicina e linezolida foi determinada atrav?s do uso de E-test e a presen?a dos genes mecA e cfr foi confirmada pela t?cnica da Rea??o em Cadeia da Polimerase. Algumas amostras tiveram a regi?o V da subunidade 23S do gene do rRNA sequenciadas e analisadas. Posteriormente, as mesmas foram submetidas a t?cnica do PFGE para determina??o do seu pulsotipo. Dos 43 estafilococos coagulase negativos resistentes ? oxacilina inclu?dos neste estudo, 33 (77%) foram identificados como S. epidermidis, 6 (14%) como S. haemolyticus, 3 (7%) como S. homins e 1 (2%) como S. capitis. Os isolados de hemocultura representaram 86% (37) e os de ponta de cateter 14% (6). As amostras apresentaram um perfil de multirresist?ncia, uma vez que 42 dos 43 isolados apresentaram resist?ncia ? 4 ou mais classes de drogas. Todas apresentaram o gene mecA. Nenhuma amostra apresentou resist?ncia ? vancomicina. Tr?s cepas de S. hominis e duas de S. epidermidis, apresentaram resist?ncia ? linezolida com CIM variando entre 6 e 64 ?L/mL. Quando investigadas, apresentaram duas muta??es pontuais (C2190T e G2603T) na regi?o V do gene para rRNA 23S. Nenhuma destas apresentou o gene cfr. O PFGE dos S. hominis revelou a presen?a de um ?nico pulsotipo em 3 hospitais, enquanto n?o foi encontrado semelhan?a gen?tica entre os S. epidermidis. Estes achados destacam a import?ncia da vigil?ncia continuada em rela??o a resist?ncia a linezolida no g?nero Staphylococcus. / Coagulase Negative Staphylococci (CoNS) belong to the normal microbiota of the skin and mucous membranes of humans and animals. The most of the infections caused by CoNS are a serious problem, since an elevated number of multi-drug resistant strains. The objective of this study was to investigate resistance to linezolid in methicillin-resistant coagulase negative staphylococci isolates from hospitals in the city of Natal. Bacterial samples were collected from spontaneous demand from Public and Private Hospitals of the city of Natal-RN. The identification staphylococci of the species were conducted by conventional biochemical. Some Samples had the identification to the species level confirmed by automated methodologies VITEK 2? and VITEK MS?. The resistance profile was evaluated with use of the disk diffusion technique (CLSI, 2013). The MIC to vancomycin and linezolid were determined by using E-test method. The antimicrobial resistance profile was evaluated by disk diffusion technique (CLSI 2013). The Minimum Inhibitory Concentration linezolid and vancomycin were determined by using E-test and the presence of the mecA gene and cfr was confirmed by the technique of Polymerase Chain Reaction. Some samples had the V region of the subunit 23S rRNA gene sequenced and subjected to PFGE technique for determining its pulsotype. Of the 43 coagulase negative staphylococci resistant to methicillin included in this study, 33 (77%) were identified as S. epidermidis, 6 (14%) as S. haemolyticus, 3 (7%) as S. homins and 1 (2%) as S. capitis. The catheter tip isolates accounted for 14% (6) and the blood culture 86% (37). Samples showed an alarming resistance profile, since 98% of the isolates were resistant to four or more class drugs. All were positive for mecA gene. No samples were resistant to vancomycin. Three S. hominis and two S. epidermidis exhibited linezolid resistance with MIC ranging from 6 to 64 ?L/mL. None of the samples had the cfr gene. When investigated, they showed two point mutations each (C2190T and G2603T) in the V region of the 23s rRNA gene. None of them was the cfr gene. The S.hominis of PFGE showed the presence of a single pulsotype in three hospitals, suggesting a clonal spread, while it was not found genetic similarity among S. epidermidis. These findings highlight the importance of continued vigilance of linezolid resistance in the genus Staphylococcus.
85

Pesquisa de Staphylococcus coagulase positiva meticilina resistente e prospecção de plantas medicinais para seu controle

Chaffe, Anna Beatriz Pizarro 29 May 2014 (has links)
Submitted by Ubirajara Cruz (ubirajara.cruz@gmail.com) on 2016-09-14T12:35:40Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_anna_chaffe.pdf: 1013600 bytes, checksum: c74b0933541fa24344b4f7bfa852c454 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2016-09-14T17:58:58Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_anna_chaffe.pdf: 1013600 bytes, checksum: c74b0933541fa24344b4f7bfa852c454 (MD5) / Made available in DSpace on 2016-09-14T17:58:58Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_anna_chaffe.pdf: 1013600 bytes, checksum: c74b0933541fa24344b4f7bfa852c454 (MD5) Previous issue date: 2014-05-29 / Sem bolsa / Staphylococcus spp é uma bactéria gram positiva ubíquo na natureza, freqüentemente presente na pele e mucosas de animais, inclusive nos seres humanos. Esse gênero está envolvido numa série de enfermidades localizadas, como infecções de feridas cutâneas ou mais profundas, mastite, otite externa e média; e em enfermidades sistêmicas, neste caso, fortemente relacionadas a procedimentos invasivos, tanto em medicina humana como veterinária. O objetivo deste trabalho foi avaliar a importância de Staphylococcus coagulase positivo meticilina resistente (MRSA) em cães hígidos domiciliados e não-domiciliados (mucosa nasal e anal), cães com enfermidades de pele (dermatite) e otite (local enfermo), leite de quartos bovinos mastísticos, estudantes do Curso de Medicina Veterinária - UFPel (mucosa nasal) e trabalhadores em saúde animal (mucosa nasal), bem como prospecção de plantas medicinais como alternativas de controle. Foram coletadas amostras de cães hígidos domiciliados com proprietário (n ≥ 83) e cães hígidos não domiciliados (n ≥ 83), estes últimos recolhidos ao módulo canil do Centro de Controle de Zoonoses da Prefeitura Municipal de Pelotas, RS. Cães com enfermidades de pele ou otite (n > 50) foram angariados junto a clinicas particulares e nos serviços de atendimento do Hospital Veterinário (HCV) da Faculdade de Veterinária - UFPel. Estudantes de veterinária do curso de Medicina Veterinária da UFPel (n = 83) e trabalhadores em saúde animal (nº não inferior a 50) foram convidados a participar do projeto. Amostras de leite de quartos bovinos mastísticos (n > 500) foram obtidas da rotina de trabalho do Laboratório de Doenças Infecciosas e de produtores da região sul do Rio Grande do Sul. Foi avaliada a atividade “in vitro” de extratos hidralcoólicos de 5 plantas com indicativo etnográfico, como carqueja (Baccharis trimera), capim-limão (Andropogon ceriferus), jambolão (Syzygium cumini), aroeira (Schinus terebinthifolius raddi), chinchilho (Tagetes minuta L.), frente a 9 cepas de Staphylococcus coagulase positivo meticilina resistente (MRSA), nas quais foram testadas através de uma triagem, com posterior cálculo da Concentração Inibitória Mínima (CIM) realizado pelo método de diluição em micro placa (Schuch, 2007). Os procedimentos laboratoriais foram executados no Laboratório de Doenças Infecciosas da Faculdade de Veterinária UFPel. Os resultados indicaram que amostras isoladas de cães hígidos domiciliados e não domiciliados apresentam S. coagulase positiva sendo que as amostras de cães não domiciliados apresentaram maior freqüência de Staphylococcus spp. (80%), S. coagulase positiva (44,3%) e S. meticilina resistente (MRSA) (10,3%), comparada às amostras de cães domiciliados. Os cães na faixa de um a seis anos apresentaram-se em maior número, sendo 107 amostras isoladas em relação às outras faixas de idade (n=192). Os cães de porte médio (n = 93) apresentaram maior percentual de S. coagulase positiva e resistência a meticilina. Não houve diferença significativa em relação ao sexo dos animais. Nas amostras isoladas de cães com otite (n = 53) / dermatite (n = 9) observa-se uma maior freqüência para Staphylococcus coagulase positiva e resistência a meticilina nas amostras coletadas de cães com otite. Foram também avaliadas as amostras S. coagulase positivas resistentes em relação à idade, porte, sexo, pelagem e espécies encontradas. Em amostras de leite de bovinos com mastite (n = 497) observou-se um percentual de 32,8% de amostras isoladas S. coagulase positiva e 9,7% S. coagulase positivas meticilina resistentes (MRSA). Em 83 amostras nasais de alunos da graduação da Faculdade de Veterinária a maior representatividade de amostras S. coagulase positiva e S. coagulase positiva meticilina resistente ocorreu em alunos que estavam acima do 7° semestre, em relação ao total de amostras positivas para Staphylococcus spp (n=66) representando 20% de S. coagulase positiva resistência à meticilina. Dos 60 trabalhadores, 9% (n=43) eram do sexo feminino onde 7% (n=28) eram veterinários e 20% (n=5) serventes com amostras nasais coagulase positiva resistente à meticilina. Entre todas as amostras de Staphylococcus coagulase positiva, ocorreu uma maior frequência de Staphylococcus pseudointermedius, fazendo parte da normalidade da microflora cutânea, em particular as mucosas como nariz, boca e ânus. / Staphylococcus spp is a ubiquitous gram positive bacteria in nature, often present in the skin and mucosa of animals, including humans. This genre is involved in a number of localized diseases such as skin infections or deeper wounds, mastitis, otitis externa and media; and systemic diseases, in this case closely related invasive procedures, both in human and veterinary medicine. The objective of this study was to evaluate the importance of methicillin resistant Staphylococcus coagulase positive (MRSA) in healthy dogs domiciled and non- domiciled (nasal and anal mucosa, dogs with skin diseases (dermatitis) and otitis (patient site), milk room cattle with mastitis, students from Veterinary Medicine College - UFPel (nasal mucosa) and in animal health workers (nasal mucosa), as well as exploration of medicinal plants as alternative control. Were sampled healthy dogs domiciled with the owner (n≥83) and healthy dogs not domiciled (n≥83), these last ones carried to the module Kennel Center for Zoonosis Control of the City of Pelotas, RS. Dogs with skin diseases or otitis (n>50) were raised from the private clinics and Clinic Veterinary Hospital (CVH), from Veterinary College services – UFPel. Students from Veterinary Medicine - UFPel (n=83) and workers in animal health (number not less than 50) were invited to participate of research. Milk samples from the forth cattle with mastitis (n>500) were obtained from the routine work of the Infectious Diseases Lab and producers from southern Rio Grande do Sul to "in vitro" activity wateralcoholic extracts of 5 plants was evaluated ethnographic indicative as gorse (Baccharis trimera),lemongrass(Andropogon ceriferus),jambolan(Syzygium cumini), mastic (Schinus terebinthifolius raddi), Chinchilho (Tagetes minuta L.) against to 9 strains of Staphylococcus coagulase positive methicillin resistant (MRSA) which were tested through screening, with subsequent calculation of the minimum inhibitory concentration (MIC ) performed by microplate dilution method (Schuch, 2007). Laboratory procedures were performed in the Infectious Diseases Lab, Veterinary College, UFPel. The results indicated that the samples from isolates of healthy dogs and not domiciled resident and resident dogs had a higher frequency of Staphylococcus spp (80 %), S. coagulase positive (44.3 %) and methicillin - resistant S. (MRSA) (10.3%) compared samples of pet dogs . Dogs in the range of 1 to 6 years showed up in greater numbers, being 107 samples isolated over other age groups (n=192).The medium-sized dogs (n = 93) showed a higher percentage of coagulase-positive S. and resistance to methicillin. There was no significant difference regarding to the sex of the animals. In isolates from dogs with otitis (n=53)/dermatitis (n=9) observed a higher frequency for Staphylococcus coagulase positive and methicillin resistance in the samples collected from dogs with otitis. We also rated the samples S. resistant coagulase positive in relation to age, size, sex, pelage and located species. In milk samples coming from cattle with mastitis (n=497) was observed a percentage of 32.8 % of isolated S. coagulase positive samples and 9.7 % S. Methicillin Resistant Coagulase Positive (MRSA). In 83 nasal samples from undergraduate students, Veterinary College, the most representative samples of S. coagulase positive and coagulase-positive methicillin resistant S. occurred in students 9 who were above the 7th semester in relation to total samples positive for Staphylococcus spp (n = 66) representing 20 % of coagulase-positive S. methicillin resistance. Among the 60 workers, 9 % (n=43) were female, where 7 % (n=28) were veterinarians, 20 % (n=5) servants with methicillin resistant coagulase positive nasal sample. Among all the samples of coagulase positive, were observed with most frequence Staphylococcus pseudointermedius, belonging to the usual microflora of the skin and mucous membranes, especially the nose, mouth and anus.
86

Growth and Biofilm Formation by Staphylococcus Epidermidis and Other Relevant Contaminant Bacteria During Storage of Platelet Concentrates

Greco, Carey Anne January 2011 (has links)
Coagulase negative staphylococci (CoNS) are the most prevalent bacterial contaminants of platelet concentrates (PCs), and have been implicated in severe and fatal transfusion reactions. Of this group, Staphylococcus epidermidis is most frequently identified. The preliminary objective of this thesis was to confirm that S. epidermidis could form biofilms under platelet storage conditions. This was achieved using a modified crystal violet staining assay to detect plastic-adherent bacterial cells and examination of attachment processes by scanning electron microscopy. A collection of CoNS isolated from PCs obtained from reportedly healthy donors was then assessed for biofilm-forming potential at the genetic and phenotypic level. Despite the presumable commensal origin of these isolates, a high proportion of S. epidermidis strains displayed a biofilm positive phenotype. The threat of S. epidermidis biofilm formation during platelet storage identified herein signifies that any alterations made to platelet storage protocols should be evaluated with consideration of this risk. The advent of platelet additive solutions (PASs) as an alternative to plasma for PC storage provides a relevant example, since little is known about the effect of PAS on contaminant bacteria, and vice versa. Growth and biofilm formation by S. epidermidis and the Gram-negative bacterium Serratia liquefaciens were measured in PAS- or plasma-PCs over 5 days, simulating standard platelet storage conditions, after initial inoculation with low, clinically relevant bacterial concentrations. Assays for platelet quality were performed simultaneously. Only S. liquefaciens exhibited a slower doubling time in plasma-PCs than in PAS-PCs. Biofilm formation by both species was reduced during storage in PAS-PCs, increasing bacteria availability for detection. Although S. liquefaciens adversely affected platelet quality in both media, S. epidermidis contamination did not. Ultimately, culture-based detection remains the earliest indicator of bacterial presence in PAS-PCs. Lastly, since formation of platelet-bacteria aggregates is largely based on receptor-ligand interactions, it was postulated that biofilm formation by contaminant bacteria could be abrogated by receptor shielding. Methoxypoly(ethylene glycol) was applied to covalently modify the platelet surface using a process termed ‘PEGylation’. It is herein demonstrated that PEGylation of PCs inoculated with S. epidermidis results in significantly reduced bacterial binding and biofilm formation during platelet storage.
87

Caracterização fenotípica e genotípica de espécies de staphylococcus isolados das cidades de Manaus e Porto Velho

Miyamoto, Mirna Sayuri Farias 30 June 2010 (has links)
Made available in DSpace on 2015-04-11T13:38:44Z (GMT). No. of bitstreams: 1 Dissertacao Mirna Miyamoto.pdf: 3227973 bytes, checksum: 7f5d27c4ca1e753ebe05cec66ce51343 (MD5) Previous issue date: 2010-06-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Staphylococcus aureus is a potential pathogen, accounting for 60% of infections in ICU`s and can be found in the nasopharyngeal region and also in the nasal cavity, especially in health care workers who become sources of dissemination of these microorganisms in hospital. However, the indiscriminate use of antibiotics to combat these pathogens, has caused the emergence of bacteria possessing resistance genes such as mecA. Of which are about 30 to 50% of the strains of S. aureus and more than 50% of coagulase-negative staphylococci. The CONS are increasingly becoming the target of concern in hospital environments, increasing the need for screening, prevention and control of resistant strains. Therefore, the objective of this work was the characterization of Staphylococcus sp., looking for the resistance gene and genetic mapping of S. aureus in clinical samples from the cities of Manaus and Porto Velho. The techniques used were biochemical tests, antibiogram, PCR (for 16 rRNA gene and mecA) and MLST. The four strains of CONS were found, three of Staphylococcus sciuri and S. epidermidis, characterized by phenotypic and genotypic tests. They were possessed of the methicillin resistance gene mecA. As for S. aureus studied, failed to detect the presence of the mecA gene, but gene mapping was performed from these samples with the technique of MLST, using five housekeeping genes. In this analysis we observed the formation of two large clusters between the cities of Manaus and Porto Velho, and two samples showed genetic divergence from other, thus demonstrating genetic variability between the cities of northern Brazil. The evidence related in the scientific literature, little research related to knowledge and epidemiological characterization of strains existing in the Amazon region, in this research, we discussed some questions of phenotypic analysis, characterization of new resistant strains and preparation of database for future development of biotechnological tools. / Staphylococcus aureus é um patógeno em potencial, sendo responsável por 60% das infecções nos CTIs, podendo ser encontrado na região da nasofaringe e também nas fossas nasais, principalmente em profissionais da saúde que se tornam fontes de disseminação desses micro-organismos no ambiente hospitalar. No entanto, o uso indiscriminado de antimicrobianos no combate desses patógenos, tem ocasionado o surgimento de bactérias possuidoras de genes de resistência, como o gene mecA, entre as quais, cerca de 30 a 50% das cepas de S. aureus e mais de 50% são de estafilococos coagulase-negativos são portadores deste gene. Os CONS estão cada vez mais se tornando alvo de preocupação nos ambientes hospitalares, aumentando a necessidade de rastreamento, prevenção e controle das cepas resistentes. Sendo assim, o objetivo deste trabalho foi realizar a caracterização de Staphylococcus sp., quanto a presença do gene de resistência e mapeamento genético de S. aureus em amostras clínicas das cidades de Manaus e Porto Velho. As técnicas aplicadas foram testes bioquímicos, antibiograma, PCR (para gene 16S rRNA e gene mecA) e MLST. Neste trabalho, encontramos quatro cepas de CONS, três de Staphylococcus sciuri e um S. epidermidis, caracterizados por testes fenotípicos e genotípicos, sendo estas possuidoras do gene de resistência a meticilina mecA. Quanto aos S. aureus estudados, não se detectou a presença do gene mecA, mas foi realizado o mapeamento gênico destas amostras com a técnica de MLST, utilizando cinco genes constitutivos. Nesta análise, foi observada a formação de dois grandes agrupamentos principais (clusters) entre as cidades de Manaus e Porto Velho, e duas amostras apresentaram divergência gênica das outras, demonstrando assim, variabilidade genética entre essas cidades da Região Norte do Brasil. Diante das evidências científicas na literatura, escassas pesquisas relacionadas ao conhecimento epidemiológico e caracterização das linhagens existentes na região Amazônica, nesta pesquisa, foram discutidas algumas questões de análise fenotípica, caracterizações de novas cepas resistentes e elaboração de banco de dados para futuro desenvolvimento de ferramentas biotecnológicas.
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les staphylocoques à coagulase négative dans l'écosystème des salaisons

Corbiere Morot-Bizot, Stephanie 07 July 2006 (has links) (PDF)
Certaines espèces de Staphylocoques à Coagulase Négative (SCN) sont naturellement présentes ou employées comme ferments de salaison. La diversité de cette flore au niveau des ateliers de salaisons reste mal connue en raison notamment de la difficulté à identifier les espèces de SCN. Nous avons développé une PCR spécifique pour identifier Staphylococcus xylosus, principale espèce présente dans les produits carnés fermentés. Une PCR multiplex ciblant S. xylosus et trois espèces de staphylocoques pathogènes opportunistes a été développée permettant l'identification de ces espèces et du genre Staphylococcus. Ces méthodes et des méthodes complémentaires basées sur la caractérisation des souches par analyse en PFGE après restriction de l'ADN, par séquençage du gène sodA et par hybridation avec des sondes spécifiques ont permis l'étude de la diversité des SCN d'ateliers de salaisons traditionnelles, artisanales ou industrielles. Nous avons pu montrer que, dans un atelier traditionnel n'utilisant aucun ferment, S. equorum et S. succinus ont colonisé majoritairement les produits et l'environnement alors que les espèces S. xylosus et S. carnosus habituellement utilisées comme ferments sont minoritaires et n'ont pas été retrouvées au niveau des produits finis. Le suivi de S. carnosus et S. xylosus, utilisés comme ferments dans un atelier artisanal et un industriel, a révélé qu'ils ne colonisent pas l'environnement et que S. xylosus devient dominant dans les produits. Il pourrait être intéressant de développer de nouveaux ferments appartenant aux espèces S. equorum ou S. succinus qui semblent adaptées à l'environnement carné.
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Coagulase-negative staphylococci in prosthetic hip infections /

Nilsdotter, Åsa, January 2005 (has links) (PDF)
Diss. (sammanfattning) Linköping : Linköpings universitet, 2005. / Härtill 5 uppsatser.
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The epidemiology and consequences of wound infections caused by coagulase negative staphylococci after thoracic surgery /

Tegnell, Anders, January 2002 (has links) (PDF)
Diss. (sammanfattning) Linköping : Univ., 2002. / Härtill 5 uppsatser.

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