O presente trabalho teve por objetivo investigar a microbiota de canais radiculares relacionadas ao insucesso do tratamento endodôntico, buscando a identificação e a quantificação destes micro-organismos. Foram selecionados 36 dentes com infecção endodôntica persistente. O material obturador foi removido do canal radicular e amostras microbiológicas foram coletadas dos canais com o auxílio de limas tipo Hedströen e cones de papel absorvente estéril. A técnica do Checkerboard DNA-DNA hybridization foi utilizada para detecção de até 79 espécies bacterianas em cada amostra, utilizando sondas de DNA específicas. Os dados microbiológicos foram expressos em percentagem média (prevalência), proporção e nível médio de cada espécie em cada amostra. Os testes t independente e de correlação de Pearson foram usados para correlacionar a contagem das bactérias testadas com os dados clínicos (p&#8804; 0,05). Foi encontrada uma média de 11 espécies por amostra. E. faecium (36%), S. epidermidis (36%), E. saburreum (28%), P. micra (28%), S. sanguis (28%), C. sputigena (28%), L. buccalis (28%), E. faecalis (28%) e S. warneri (28%) foram as espécies mais prevalentes, e as espécies encontradas em níveis médios mais altos foram E. faecium, D. pneumosintes, S. epidermidis, H. pylori e C. sputigena. T. socranskii (3%), F. periodonticum (3%), C. gingivalis (3%), S. ixodetis (3%) apresentaram prevalências mais baixas. E. faecium e S. epidermidis apresentaram os maiores valores de prevalência, níveis médios e proporção. Não houve correlação entre a microbiota detectada nas amostras com os sinais e sintomas clínicos apresentados pelos pacientes, porém nas lesões periapicais de maior área foi detectada contagem significativamente maior de bacilos e espécies Gram-negativas (p<0,05). Baseado nos resultados obtidos é possível concluir que a microbiota presente em dentes com periodontite apical persistente possui perfil misto e complexo, e que uma maior área de lesão perirradicular pode estar associada a contagem elevada de bacilos e de espécies Gram-negativas. / The present study investigated the composition of the root canal microbiota in endodontic failures, aiming to identify and quantify these microorganisms. Thirty six teeth with persistent endodontic infection were selected. The root-filling materials were removed and microbiological samples were taken from the root canals with a Hedströen-type file and sterile paper points. The Checkerboard DNA-DNA hybridization technique was used for the detection of 79 bacterial species in each sample, using specific DNA probes. Microbiological data were express in mean prevalence, proportions and levels of each species in each sample. t independent test and Pearson correlation test were use to correlate bacterial counts and clinical conditions (p&#8804; 0,05). There were found a mean of 11 different species per sample. E. faecium (36%), S. epidermidis (36%), E. saburreum (28%), P. micra (28%), S. sanguis (28%), C. sputigena (28%), L. buccalis (28%), E. faecalis (28%) and S. warneri (28%) were the most prevalent species, and the species found in highest mean levels were E. faecium, D. pneumosintes, S. epidermidis, H. pylori and C. sputigena. T. socranskii (3%), F. periodonticum (3%), C. gingivalis (3%) and S. ixodetis (3%) were found in low prevalence. E. faecium and S. epidermidis presented the highest values of prevalence, means levels and proportions. No correlation was found between the detected microbiota and clinical findings; however in periapical lesions with highest areas, higher levels of rods and Gram-negative species were detected (p<0.05). Based on these results it may be concluded that the microbiota in teeth with persistent apical periodontitis presents a mixed and complex profile, and periapical lesions with larger area might be high associated with higher counts of rods and Gram-negative species.

O uso de diferentes tipos de medicação intracanal para o controle do processo infeccioso, principalmente nos casos em que há presença de microrganismos resistentes às manobras de desinfecção, tem sido alvo de muitas pesquisas. A proposta deste estudo foi avaliar, in vitro, o efeito antimicrobiano de bacteriófagos específicos diante de cinco cepas de Enterococcus faecalis e a ação de um lisado híbrido polivalente na eliminação da infecção causada por essas cinco cepas da mesma espécie. Foram utilizados 37 dentes unirradiculares humanos, recentemente extraídos e de proporções aproximadas. As coroas foram removidas e os canais instrumentados até a lima tipo K de número 45. Os espécimes foram, então, esterilizados e utilizados em dois experimentos distintos. O primeiro experimento utilizou 25 raízes divididas em cinco grupos de cinco espécimes. Três espécimes de cada grupo foram inoculados com uma das culturas bacterianas e seus fagos correspondentes na proporção 1:1, por um período de três horas a 37 °C, enquanto os outros dois, receberam a cultura de microrganismos ou somente meio de cultura (controle positivo e negativo, respectivamente). No segundo experimento, 11 espécimes receberam um inóculo formado pelas cinco cepas por um período de 10 dias de incubação a 37 °C, com o propósito de manter condições apropriadas para a penetração das bactérias no interior dos túbulos dentinários, e um outro espécime recebeu apenas meio de cultura (controle negativo). Essa penetração foi confirmada empregando-se microscopia ótica e eletrônica realizada em dois espécimes. Após o período de incubação, o lisado polivalente, preparado com os cinco fagos, foi aplicado por 24 horas a 37 °C em 8 espécimes, e os demais preenchidos com meio de cultura (controle positivo e negativo). Alíquotas do interior de todos os canais foram colhidas antes e depois do contato com os fagos e no segundo experimento, também 24 e 48 horas depois, para semeadura e contagem de unidades formadoras de colônia. Os resultados do primeiro experimento mostraram 100% de redução do crescimento bacteriano nos espécimes que receberam a suspensão de fagos específicos, em comparação a seus respectivos controles positivos, em todos os grupos. No segundo experimento, foi comparado o crescimento obtido após os 10 dias de infecção com aquele posterior a aplicação dos fagos, redução que variou entre 50% e 100%. Diante desses resultados, conclui-se que os bacteriófagos foram eficazes na diminuição dos microrganismos presentes no interior de canais radiculares e nos túbulos dentinários de dentes humanos. / Many studies have investigated different intracanal medications to control infection processes, especially in cases of microbial resistance to disinfection procedures. The purpose of this study was to evaluate the in vitro antimicrobial effect of specific bacteriophages on five isolates of Enterococcus faecalis, as well as the activity of a lysate cocktail in eliminating the infection caused by these bacteria. Thirty-seven recently extracted human teeth of approximately equal size and with single roots were used. The crowns were removed and each canal was prepared using K files,up to # 45, and sterile physiological saline. Specimens were then sterilized and used in two separate studies. The first study utilized 25 individual roots divided into five groups of five specimens each. Three specimens of each group were inoculated with one of the bacterial cultures and the corresponding bacteriophage in a proportion of 1:1, and incubated for three hours at 37°C; the other two specimens were inoculated with only the bacterial culture or only the culture medium (positive and negative controls, respectively). In the second study, 11 specimens were inoculated with all five strains and incubated for ten days at 37°C in order to allow bacteria to penetrate the interior of the dental tubules, and another one, received just the culture medium (negative control). Penetration into the tubules was confirmed by optical and electron microscopy of two specimens. Following incubation, the lysate cocktail prepared using all five bacteriophages was applied to the other 8 specimens for 24 hours at 37°C, and 2 specimens were filled with the culture medium (positive and negative controls). In the first study, samples were taken from the lumen of all canals before and after contact with bacteriophages; in the second, aliquots were also taken 24 and 48 hours after the bacteria were exposed to the phages. All samples were diluted and plated and the number of colony forming units was counted. In the first study, there was a 100% reduction in bacterial growth in specimens that received the specific bacteriophage suspension compared to the positive controls within each group. In the second study, after ten days the number of bacteria was reduced by 50% to 100% following the bacteriophage application. These results suggest that bacteriophages are effective in reducing the number of bacteria inside the root canal and in the dental tubules of human teeth.

Made available in DSpace on 2014-08-20T14:38:03Z (GMT). No. of bitstreams: 1 dissertacao_clarissa_castro.pdf: 569054 bytes, checksum: b9876922c1664dec56ef9c9d4ff5cb3a (MD5) Previous issue date: 2011-03-31 / The enzootic bovine leukosis is an illness caused by the bovine leukosis virus (BLV) which provokes a persistent infection in cattle and is responsible for significant economical losses to the bovines, mainly dairy cattle. It is widely spread in Brazilian cattle and it can come up in three forms: asymptomatic infection, persistent lymphocytosis and lymphosarcoma. The animals that have antibodies against the BLV must be eliminated or separated from the rest of the cattle, because they are carriers and disseminators of the virus during all their lifetimes. The diagnosis of this disease is essential for control and eradication strategies based on the segregation of infected animals in order to avoid or attenuate the transmission of the virus, and consequently, minimize the economical losses caused by the disease. During the BLV infection antibodies are produced against the main viral proteins, gp 51, gp 30 (envelope glicoproteins) and p24 (capsid protein). The agar gel immunodiffusion (AGID) and the enzyme-linked immunosorbent assay (ELISA) tests are the most used for diagnosis. In this report the immunoperoxidase technique (peroxidase linked assay - PLA) was evaluated in order to detect antibodies against the BLV. The results obtained in the PLA were compared with the AGID test and the specificity of the positive ones was confirmed by the Western blotting (WB) technique. Two hundred and one bovine serum samples of cattle coming from the city of Pelotas were tested: 59% (119) were positive in PLA and 26% (53) were positive in AGID. All the AGID positive samples were also PLA positive. From the 32,8% (66) of the conflicting serum results just eight were confirmed as positive in WB, indicating that the rest of the results were false-positive and showing that AGID failed in identifying 4% of the BLV positive animals. The PLA technique for the diagnosis of the BLV infection demonstrated to be very useful to use in control programs because it was more sensitive when compared to the AGID technique. However, the occurrence of false-positive results by the PLA makes its use unviable in eradication programs that involve the sacrifice of seropositive animals. / A leucose enzoótica dos bovinos (EBL) é uma enfermidade causada pelo vírus da leucose bovina (BLV), que ocasiona uma infecção persistente em bovinos, e é responsável por perdas econômicas significativas à pecuária, principalmente a leiteira. Amplamente disseminada no rebanho brasileiro, pode ser manifestada de três formas: aleucêmica, linfocitose persistente e linfossarcoma. Os animais com anticorpos contra o BLV deverão ser eliminados ou separados do restante do rebanho, pois significa que são portadores e disseminadores do vírus por toda a vida. O diagnóstico desta doença é essencial para estratégias de controle e erradicação baseadas na segregação de animais infectados no intuito de evitar ou amenizar a transmissão do vírus e, consequentemente, minimizar as perdas econômicas causadas pela doença. Durante a infecção pelo BLV são produzidos anticorpos contra as principais proteínas virais, gp51, gp30 (glicoproteínas do envelope) e p24 (proteína do capsídeo). O teste de imunodifusão em gel de ágar (agar gel immunodiffusion AGID) e o ensaio imunoenzimático (enzyme-linked immunosorbent assay ELISA) são os mais utilizados para diagnóstico. No presente trabalho foi avaliada a técnica de imunoperoxidase (peroxidase linked assay PLA) na detecção de anticorpos contra o BLV. Os resultados obtidos na PLA foram comparados com o teste de AGID e a especificidade dos positivos confirmada pela técnica de Western blotting (WB). Foram testadas 201 amostras de soro de bovinos provenientes de propriedades localizadas no município de Pelotas: 59% (119) foram positivos por PLA e 26% (53) positivos por AGID. Todas as amostras positivas na AGID foram também positivas na PLA. Dos 32,8% (66) dos soros com resultados conflitantes apenas oito foram confirmados como positivos no WB, indicando serem falso-positivos os demais resultados e constatando que a AGID falhou em identificar 4% de animais positivos para EBL. A técnica de PLA para diagnóstico de infecção pelo BLV se mostrou muito útil para uso em programas de controle devido à maior sensibilidade da técnica quando comparada com o teste de AGID. Contudo, a ocorrência de resultados falso-positivos pela PLA inviabiliza o seu uso em programas de erradicação que envolva o sacrifício do animal soropositivo.

Les entérovirus du groupe B (EV-B) sont une cause majeure de myocardite aiguë, précurseur de la myocardite chronique et de la cardiomyopathie dilatée (CMD) chez l’homme. Les mécanismes moléculaires viraux impliqués dans la progression de la myocardite aiguë vers la phase chronique et la CMD restent inconnus. En utilisant une approche NGS, nous avons détecté des populations persistantes majoritaires d’EV-B tronquées en extrémité 5’, associées à des formes complètes mineures dans des cas de CMD. Afin évaluer leur impact sur la fonctionnalité des cardiomyocytes, nous avons transfecté dans des cardiomyocytes primaires (HCM) des ARN viraux clonés et identiques à ceux détectés dans les cas de CMD. Les formes EV-B majoritaires tronquées en extrémité 5’, seules ou associées à des populations complètes « auxiliaires » pourraient altérer les fonctions des HCM par des activités de la P2A virale. L'existence de mécanismes de recombinaison génomique entre les populations virales persistantes tronquées et complètes a été étudiée par un test de recombinaison d’ARN EV-B défectifs transfectés dans des HCM. Cette approche in vitro a produit majoritairement des recombinants non-homologues caractérisés par des échanges génétiques dans la région 5’NC (spacer1/2). Nos résultats indiquent l’existence d’événements de recombinaison génomique en région 5’ entre les populations d’EV-B tronquées et complètes qui pourraient contribuer au développement de la CMD. Une meilleure compréhension des mécanismes de persistance virale permettra le développement de nouvelles stratégies thérapeutiques pour lutter contre les infections chroniques par les EV-B. / Group-B Enteroviruses (EV-B) are a common cause of human acute myocarditis, a disease that is a precursor of chronic myocarditis and dilated cardiomyopathy (DCM). However, the viral molecular mechanisms involved in the progression of acute to chronic myocarditis and subsequently to DCM remain unknown. Using NGS approach, we detected persistent major EV-B populations characterized by 5’ terminal genomic deletions ranging from 17 to 50 nucleotides associated with minor complete viral forms in explanted hearts of DCM cases. To assess their impact on cardiomyocyte functions, we transfected viral RNA clones mimicking the viral genomes found in patients’ tissues into primary human cardiomyocytes (HCM). Our findings demonstrated that the major persistent 5’ deleted viral forms alone or associated with full-length populations of helper RNAs could impair cardiomyocyte functions by viral 2Apro activities in EV-DCM cases. To assess the existence of genomic recombination mechanisms between persistent deleted and full-length viral helper populations, we used a recombination assay based on the rescue of non-replicative EV-B RNAs transfected in HCM. This in vitro approach produced major (75%) non-homologous recombinants that nucleotides sequencing characterized modular exchanges into the spacers 1 & 2 of the 5’NC region. Our findings indicate the existence of genomic recombination events through which, 5’ deleted and complete collaborative EV-B populations could significantly contribute to the pathogenesis of unexplained DCM cases. A better understanding of these viral persistence mechanisms will stimulate new therapeutic strategies research for chronic infections caused by EV-B.

Equine arteritis virus (EAV) has a global impact on the equine industry being the causative agent of equine viral arteritis (EVA), a reproductive, respiratory, and systemic disease of equids. A distinctive feature of EAV infection is that it establishes long-term persistent infection in the reproductive tract of stallions and is continuously shed in the semen (carrier state). Recent studies showed that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S). However, the cellular and molecular mechanisms underlying the establishment and maintenance of persistent infection are yet to be determined. The studies were undertaken herein unequivocally demonstrated that the ampulla is the main EAV tissue reservoir rather than immunologically privileged tissues (i.e., testes) and that EAV has specific tropism for stromal cells and CD8+ T and CD21+ B lymphocytes but not glandular epithelium in the reproductive tract. Furthermore, persistent EAV infection is associated with a significant humoral, mucosal antibody and inflammatory response at the site of persistence, characterized by induction of high levels of neutralizing antibodies (IgG1), mucosal anti-EAV-specific IgA, IgG1, IgG3/5, and IgG4/7 with variable neutralizing efficacy; and moderate, multifocal lymphoplasmacytic ampullitis, with significant infiltration of T lymphocytes (mainly CD8+ and low numbers of FOXP3+ lymphocytes), CD21+ B lymphocytes, diverse Ig-secreting plasma cells, and Iba-1+ and CD83+ tissue macrophages/dendritic cells. Moreover, EAV long-term persistent infection is associated with a CD8+ T lymphocyte transcriptional profile with upregulation of T-cell exhaustion-related transcripts and homing chemokines/chemokine receptors (CXCL9-11/CXCR3 and CXCL16/CXCR6), orchestrated by a specific subset of transcription factors (EOMES, PRDM1, BATF, NFATC2, STAT1, IRF1, TBX21), which are associated with the presence of the susceptibility allele (CXCL16S). Finally, these studies have determined that long-term EAV persistence is associated with the downregulation of a specific seminal exosome-associated miRNA (eca-mir-128) along with an enhanced expression of CXCL16 in the reproductive tract, a putative target of eca-mir-128. These findings provide evidence that this miRNA plays a crucial role in the regulation of the CXCL16/CXCR6 axis in the reproductive tract of persistently infected stallions, a chemokine axis strongly implicated in EAV persistence. The findings presented herein suggest that complex host-pathogen interactions shape the outcome of EAV infection in the stallion and that EAV employs complex immune evasion mechanisms favoring persistence in the reproductive tract. Further studies to identify specific mechanisms mediating the modulation of the CXCL16/CXCR6 axis and viral immune evasion in the reproductive tract of the EAV long-term carrier stallion are warranted.

Equine arteritis virus (EAV) establishes persistent infection in the stallion reproductive tract, and the carrier stallion continues to shed virus in semen for weeks to years or lifelong. The objective of this study was to elucidate the intra-host evolution of EAV during persistent infection in stallions. Seven EAV seronegative stallions were experimentally infected with EAV KY84 strain and followed for 726 days post-infection, and sequential clinical samples including semen were collected for virus isolation and next-generation sequencing (NGS). In addition, archived sequential semen samples from two stallions that were naturally infected with EAV KY84 for a long-period (up to 10 years) were also sequenced by NGS. The data demonstrated genetic bottleneck event and selection during acute infection followed by intra-host quasispecies diversification during persistent infection in the stallion reproductive tract. Also, the full-length genome of a novel EAV donkey strain from Chile and a noncytopathic bovine viral diarrhea virus-1 (ncpBVDV-1) strain contaminating rabbit kidney-13 cells were also sequenced by NGS. The EAV donkey strain was genetically distinct but antigenically cross-reacted with EAV antisera, and it was phylogenetically closely related to the South African donkey strain of EAV. Genetic and phylogenetic analyses demonstrated that ncpBVDV-1 belongs to BVDV-1b group.