The IDSA Community-Acquired Pneumonia (CAP) Guideline recommends ceftriaxone in combination with doxycycline as an alternative to combination therapy with ceftriaxone and azithromycin for non-intensive care unit (ICU) patients hospitalized with CAP. This is an attractive alternative regimen due to recent concerns of increased cardiovascular risk associated with azithromycin. The objective of this study was to compare the clinical outcomes of azithromycin and doxycycline each in combination with ceftriaxone for non-ICU Veterans hospitalized with CAP.

Nonobstant d’immenses progrès accomplis depuis des décennies dans la prise en charge des patients soumis à la ventilation mécanique, les pneumonies acquises sous ventilation mécanique continuent de compliquer le séjour en réanimation de près de 28% des patients recevant une assistance respiratoire invasive prolongée. Parmi les malades des unités de soins intensifs, le risque de développer une pneumonie est de 3 à 10 fois supérieur chez les intubés sous ventilation. Elle reste cependant bien souvent le seul moyen de venir en aide aux patients souffrant de graves détresses respiratoires. Il a maintenant été clairement démontré que la ventilation mécanique, en particulier lorsqu’elle est mise en place selon des stratégies dites agressives, active les cellules pulmonaires conduisant alors à une réponse pro-inflammatoire même en l’absence de pathogène. Ce phénomène est connu sous le terme de biotrauma, et serait responsable en partie des lésions induites sur le poumon par la ventilation mécanique. En quelques sortes, la ventilation mécanique prépare les cellules épithéliales pulmonaires à répondre massivement à une seconde agression pro-inflammatoire par la libération de grandes quantités de cytokines (comme l’IL-8 notamment), accentuant alors les lésions du tissu pulmonaire essentiellement par le recrutement de polynucléaires neutrophiles attirés par la sécrétion massive d’IL-8. L’immunité innée joue donc un rôle très important dans le développement du VILI. L’implication des Toll Like Récepteurs a été suggérée par plusieurs études expérimentales. Par ailleurs, la ventilation en décubitus ventral a été décrite pour avoir des effets bénéfiques sur les patients ventilés souffrant de graves lésions pulmonaires particulièrement chez ceux souffrant du syndrome de détresse respiratoire aiguë. Notre équipe s’est particulièrement intéressée au TLR2, qui reconnait les bactéries à Gram-positif, car elle a montré dans des études précédentes in vitro que l’étirement cyclique de cellules pulmonaires humaines augmentait principalement l’expression de TLR2 ainsi que la réactivité de cellules pulmonaires à des composants de la paroi de bactéries à Gram positif. Ces données ont par la suite été confirmées dans un modèle in vivo de lapins ventilés dont la réponse immune innée était stimulée par du Pam3CSK4.Dans un premier projet, nous avons évalué l’impact d’une ventilation mécanique en décubitus ventral chez des lapins avec pneumonie unilatérale à Enterobacter aerogenes soumis à la ventilation mécanique. Nos résultats montrent que le décubitus ventral peut être protecteur si l’hôte est soumis à la ventilation mécanique dans le contexte d’une pneumonie bactérienne unilatérale.Pour vérifier la pertinence de nos hypothèses sur le TLR2 dans notre modèle animal de pneumonie acquise sous ventilation mécanique, nous avons mené des expériences avec des bactéries vivantes reconnues par le TLR2 (une souche de Staphylococcus aureus résistante à la methicilline SARM). Notre étude met en évidence qu’une ventilation mécanique modérément agressive impacte sur la clairance bactérienne pulmonaire en la diminuant, aggrave les lésions sur le tissu pulmonaire et favorise une réponse inflammatoire systémique. La surexpression du TLR2 tant au niveau pulmonaire que systémique pourrait expliquer ces résultats.Le troisième projet s’est attaché à évaluer l’impact d’une thérapie aux statines dans le contexte d’une pneumonie acquise sous ventilation mécanique à SARM, conjointement traitée par le linezolide, dans notre modèle animal de lapins ventilés. Nos résultats suggèrent qu’une pré-­‐exposition aux statines pourrait avoir un effet anti-inflammatoire au niveau pulmonaire et systémique dans ce modèle, qui pourrait passer par une régulation négative de l’expression de TLR2, contre-balançant les effets de l’étirement cyclique. / Despite major advances since decades in the management of ventilated patients, ventilator-associated pneumonia (VAP) continues to complicate the course of approximately 28% of the patients receiving mechanical ventilation (MV). Among patients hospitalized in intensive care units, the risk of pneumonia is 3- to 10- fold increased in MV patients. However, MV is often the only way to care for critically ill patients with respiratory failure. It has now been clearly demonstrated that MV, in particular adverse ventilatory strategies could activate lung cells, thus leading to a proinflammatory response, even in the absence of pathogen. This is the biotrauma paradigm, which accounts, at least in part, for the ventilator induced lung injury (VILI). In one way, MV primes airway cells to respond massively to a second proinflammatory insult, through the subsequent release of large amounts of cytokines (as interleukin (IL)‐ 8), thus leading to additional lung injury, particularly through the recruitment of neutrophils attracted by the massive release of IL-8. Accordingly, innate immunity plays an important role in the developement of VILI. The involvement of Toll-like receptors has been suggested by several experimental studies. Ventilation in the prone position (PP) has been described to have beneficial effects on patients under MV, especially in those with lobar involvement. Our team focused particularly on the TLR2, which interacts with Gram-positive bacteria, and we have previously demonstrated in vitro that cyclic stretch of human pulmonary cells resulted in TLR2 overexpression and enhanced TLR2 reactivity to Gram-positive cell wall components. We confirmed these datas in an in vivo model of ventilated rabbits which immune response had been stimulated with Pam3CSK4. In a first project, we assessed the impact of the PP on unilateral pneumonia to Enterobacter aerogenes in rabbits subjected to MV. Our results shows that the prone position could be protective if the host is subjected to MV and unilateral bacterial pneumonia. To ensure the relevance of our hypothesis on TLR2 in our animal model of VAP, we conducted experiments using live bacteria specifically recognized by TLR2 (Methicilin resist. aureus). We demonstrate that mild-­‐stretch MV impaired lung bacterial clearance, hastened tissue injury and promoted a systemic inflammatory response. Both pulmonary and peripheral blood TLR2 overexpression could account for such an impact. The third project assessed the impact of a statins therapy in the context of MRSA VAP, treated with linezolid, in our model of ventilated rabbits. Our results suggest that statin exposure prior to pneumonia provides an anti-­‐inflammatory effect within the lung and the systemic compartment of rabbits with MRSA VAP. Although LNZ enhances pulmonary bacterial clearance, dampening the host systemic inflammatory response with statin could impede defense against MRSA in this compartment. It could be subsequent to enhanced antibacterial defences and improvements in lung mechanics, thereby blunting overwhelming inflammation. In the last project, in collaboration with the University of Geneva, we assessed whether mitochondrial alarmins are released during VILI and can generate lung inflammation. Our results confirmed the hypothesis made and showed indeed that alarmins are released during during cyclic stretch of human epithelial cells, as well as in BAL fluids from rabbits ventilated with an injurious ventilatory regimen. These alarmins stimulate lung cells to produce bioactive IL-­‐1, and are likely to represent the proximal endogenous mediators of VILI and ARDS, released by injured pulmonary cells.

A pneumonia associada à ventilação mecânica (PAVM) é uma infecção freqüente nas Unidades de Terapia Intensiva (UTI), acarretando aumento no período de hospitalização, nos índices de morbimortalidade e com repercussão significativa nos custos. A implementação de medidas específicas para a prevenção da PAVM é baseada em diretrizes para a prática clínica, elaboradas por órgãos governamentais e associações de especialistas. Nesse sentido, é importante destacar a necessidade de atualização permanente dos profissionais da saúde. Frente ao exposto, objetivouse avaliar e descrever as evidências científicas disponíveis sobre as práticas de prevenção da PAVM, em pacientes adultos, hospitalizados em UTI. A prática baseada em evidências representou o referencial teórico-metodológico. E, para a obtenção das evidências de Níveis I e II, publicadas posteriormente à diretriz do CDC, realizou-se a revisão integrativa da literatura nas bases de dados MEDLINE, LILACS, CINAHL e Biblioteca Cochrane. Totalizou-se 23 publicações, agrupadas nas categorias temáticas: 5 (22%) higienização bucal, 7 (30%) aspiração de secreções, 5 (22%) umidificação das vias aéreas, 3 (13%) posicionamento do paciente e 3 (13%) diretrizes para a prática clínica. O uso da clorexidina na higienização bucal de pacientes sob ventilação mecânica diminuiu a colonização da orofaringe, o que pode reduzir a incidência de PAVM. Em adição, a aspiração da secreção subglótica e a terapia cinética mostraram-se medidas eficazes na prevenção da PAVM. Por outro lado, o uso do sistema fechado para a aspiração endotraqueal, a umidificação das vias aéreas com o dispositivo HME (heat and moisture exchanger), o controle da pressão do balonete do tubo endotraqueal, bem como, o posicionamento semirecumbente do paciente não apresentaram impacto na prevenção da PAVM e configuram como questões controversas. Assim, outras pesquisas são necessárias, especialmente, para elucidar questionamentos e implementar novas tecnologias acerca das medidas de prevenção da PAVM, o que sem dúvida repercutirá na qualidade da assistência de pacientes submetidos à ventilação mecânica. / Ventilator-associated pneumonia (VAP) is a common infection in the Intensive Care Unit (ICU), which leads to a longer period of hospitalization, higher rates of morbidmortality and a significant repercussion on the costs. The implementation of specific measures to prevent VAP is based on clinical practice guidelines elaborated by governmental organizations and expert committees. Thus, it is important to stand out the permanent actualization of health care professionals. Therefore, this study aimed to evaluate and describe the available scientifical evidences on VAP prevention practices in adult patients hospitalized in the ICU. The evidence based practice represented the theoretical-methodological reference. And, to obtain the evidences Levels I and II, published after the CDC guideline, an integrative review of the literature of MEDLINE, LILACS, CINAHL and Cochrane Library databases was realized. A total of 23 publishing grouped in categories: 5 (22%) oral hygiene, 7 (30%) aspiration of secretions, 5 (22%) airways moisturizing, 3 (13%) patient positioning and 3 (13%) clinical practice guidelines. The use of chlorhexidine in the oral hygiene of the mechanical ventilated patients decreased the oropharyngeal colonization, which may decrease VAP incidence. Besides, the subglottic secretions drainage and the kinetic therapy proved to be efficient on VAP prevention. However, the use of the closed system to the endotracheal aspiration, moisturizing the airways with HME (heat and moisture exchanger), the control of the pressure of the endotracheal tube cuff as well as the semirecumbent positioning of the patient, did not present any impact on the VAP prevention and are controversial matters. Thus, further researches are required mainly to clarify some questions and implement new technologies on measures to prevent VAP, which will certainly reflect on the quality of the assistance given to patients on mechanical ventilation.

INTRODUÇÃO: A síndrome da imunodeficiência adquirida (AIDS) é atualmente uma pandemia, e as doenças pulmonares são a principal causa de morbidade e mortalidade dos pacientes com AIDS. Nesse sentido, as infecções respiratórias são frequente causa de hipoxemia e morte. Os pacientes com AIDS e insuficiência respiratória hipoxêmica frequentemente necessitam de ventilação mecânica invasiva, a qual é independentemente associada com mortalidade. A ventilação não invasiva com pressão positiva refere-se à oferta de assistência ventilatória mecânica sem a necessidade de invasão artificial das vias aéreas, sendo reconhecida por melhorar a oxigenação e a dispneia dos pacientes com insuficiência respiratória hipoxêmica, principalmente se aplicada de forma sequencial e progressiva, e esta pode reduzir a necessidade de ventilação mecânica invasiva nestes pacientes. Tendo em vista as incertezas quanto à resposta da oxigenação a PEEP nos pacientes com AIDS com insuficiência respiratória aguda hipoxêmica e usando o racional da pressurização progressiva das vias aéreas e seu potencial benefício na oxigenação sanguínea, nós fizemos a hipótese de que o incremento sequencial dos níveis de PEEP até 15 cmH2O pode melhorar a oxigenação sanguínea sem afetar o conforto e a hemodinâmica do paciente. O objetivo principal deste estudo foi investigar os efeitos de diferentes sequências de níveis de PEEP aplicado de forma não invasiva sobre as trocas gasosas, a sensação de dispneia e os padrões hemodinâmicos em pacientes com AIDS e insuficiência respiratória aguda hipoxêmica. O objetivo secundário foi avaliar o tempo livre de ventilação mecânica invasiva em 28 dias e a mortalidade hospitalar em 60 dias. MÉTODOS: Foram estudados 30 pacientes adultos com HIV/AIDS e insuficiência respiratória aguda hipoxêmica. Todos os pacientes receberam uma sequência randomizada de PEEP não invasivo (os valores usados foram 5, 10 ou 15 cmH2O) por vinte minutos. A PEEP foi fornecida através de máscara facial com pressão suporte (PSV) de 5 cmH2O e uma FiO2 = 1. Um período de washout de 20 minutos com respiração espontânea foi permitido entre cada PEEP. Variáveis clínicas e uma gasometria arterial foram registradas após cada etapa de PEEP. RESULTADOS: Analisando os 30 pacientes, a oxigenação melhorou linearmente com a elevação da PEEP, contudo, estudando os pacientes conforme a PEEP inicial randomizada, a oxigenação foi similar independentemente da primeira PEEP randomizada (5, 10 ou 15 cmH2O), e somente o subgrupo com PEEP inicial = 5 cmH2O melhorou mais a oxigenação quando PEEPs maiores foram usadas. A PaCO2 também aumentou junto com a elevação da PEEP, especialmente com uma PEEP = 15 cmH2O. O uso de PSV = 5 cmH2O foi associado com significante e consistente melhora da sensação subjetiva de dispnéia e da frequência respiratória com PEEP de 0 a 15 cmH2O. CONCLUSÕES: Os pacientes com SIDA e insuficiência respiratória hipoxêmica melhoram a oxigenação com a elevação progressiva e sequencial da PEEP até 15 cmH2O, contudo a elevação da PaCO2 limita a PEEP até 10 cmH2O. Uma PSV = 5 cmH2O promove uma melhora da sensação subjetiva da dispnéia independentemente do uso de PEEP / INTRODUTION: The acquired immunodeficiency syndrome (AIDS) is a pandemic, and lung diseases are the leading cause of morbidity and mortality and are often associated with respiratory infections, hypoxemia and death. The noninvasive ventilation with positive pressure refers to the provision of mechanical ventilatory assistance without the need for artificial airway invasion, being recognized for improving oxygenation and dyspnea in patients with hipoxemic respiratory failure. Patients with AIDS and hypoxemic respiratory failure often require invasive mechanical ventilation, which is independently associated with mortality. Given the uncertainties about response in oxygenation with PEEP in patients with AIDS with acute hypoxemic respiratory failure and using the rational for progressive pressurization of the airway and its potential benefits on blood oxygenation, we made the hypothesis that increased levels of sequential PEEP up to 15 cmH2O may improve blood oxygenation without affecting the comfort and hemodynamics of the patient. The main objective of this study was to investigate the effects of different sequences of PEEP levels on gas exchange, the sensation of dyspnea and hemodynamics in patients with AIDS and acute hypoxemic respiratory failure. The secondary objective was to assess the time free of invasive mechanical ventilation in 28 days and hospital mortality within 60 days. METHODS: We studied 30 adults patients with HIV/AIDS and acute hypoxemic respiratory failure. All patients received a randomized sequence of noninvasive PEEP (the values used were 5,10 or 15 cmH2O) for twenty minutes. PEEP was delivered via face mask with pressure support (PSV) of 5 cmH2O and FiO2 = 1. A washout period of 20 minutes with spontaneous breathing was allowed between each PEEP trial. Clinical variables and arterial blood gases were recorded after each PEEP step. RESULTS: Analyzing the 30 patients, oxygenation improved linearly with increasing PEEP, however studying the patients randomized according to the initial PEEP, oxygenation was similar regardless of the first randomized PEEP (5,10 or 15 cmH2O), and only the subgroup with initial PEEP = 5 cmH2O further improve the oxygenation when high PEEP were used. The PaCO2 also rose beside the PEEP elevation, especially with a PEEP = 15 cmH2O. The use of PSV = 5 cmH2O was associated with significant and consistent improvement of subjective sensation of dyspnea and respiratory rate with a PEEP from 0 to 15 cmH2O. CONCLUSION: AIDS-patients with hypoxemic respiratory failure improve oxygenation with a progressive sequential elevation of PEEP up to 15 cmH2O, however the elevation of PaCO2 limit the PEEP up to 10 cmH2O. A PSV = 5 cmH2O promotes an improvement of subjective sensation of dyspnea independently from the use of PEEP

Pacientes com comprometimento pleural por neoplasias malignas freqüentemente apresentam derrame pleural recidivante. Nestes casos, a sínfise das membranas pleurais (pleurodese) com a finalidade de evitar o acúmulo de líquido no espaço pleural deve ser considerada. O talco é o agente mais utilizado indicado para essa finalidade. Entretanto, seu uso terapêutico continua controverso devido aos efeitos deletérios que podem advir de sua utilização. O mais grave entre todos é a insuficiência respiratória aguda, que pode evoluir para a síndrome do desconforto respiratório agudo (SDRA). Essa complicação pode estar relacionada com a composição, com o tamanho das partículas de talco e com a resposta inflamatória desencadeada pelas mesmas. O objetivo deste estudo foi avaliar os efeitos pulmonares e sistêmicos em resposta à injeção intrapleural (IIP) de talco de partículas pequenas (TP) e de partículas de tamanhos diversos (TM). Cem coelhos foram submetidos à IIP com talco. Metade dos animais foi injetada com TP (diâmetro médio= 6,41 mm) e outra metade com TM (diâmetro médio= 21,15 mm), que é o talco usado na prática clínica. Quinze coelhos compuseram o grupo controle. Foram avaliados a celularidade, os níveis de desidrogenase lática (DHL), proteína C reativa (PCR), interleucina-8 (IL-8) e fator de crescimento endotelial vascular (VEGF) no sangue e no lavado broncoalveolar (LBA) às 6, 24, 48, 72 e 96 horas após a IIP. Realizou-se também a quantificação de partículas de talco e a análise histológica dos pulmões. Utilizamos o teste t e Anova na análise estatística, considerando p< 0,05 como significância estatística. A maioria dos parâmetros avaliados apresentou níveis mais elevados no sangue e no LBA dos animais injetados com TP ou TM quando comparados ao grupo controle, sugerindo uma resposta sistêmica e pulmonar à IIP de talco. Com relação aos grupos de talco, os níveis de PCR e de IL-8 apresentaram-se mais elevados no sangue e no LBA dos animais injetados com TP. Partículas de talco foram observadas em todas as lâminas examinadas, sem diferenças significativas entre os grupos. Os pulmões dos animais injetados com TP apresentaram infiltrado linfomononuclear mais exuberante que no grupo TM. A resposta inflamatória pulmonar antecedeu (24 h) a resposta sistêmica (48 h), sugerindo que o pulmão é o principal órgão da resposta sistêmica aguda. Estes achados estudo nos permitem concluir que o talco calibrado com partículas maiores deva ser utilizado na prática clínica, objetivando uma pleurodese mais segura. / Talc has been the pleurodesis agent of choice for the local treatment of recurrent pleural diseases. However, serious concerns exist about its safety. The acute respiratory failure is considered its most serious complication. The physiopathologic mechanisms involved are still unclear. It has been attributed to the systemic dissemination of small talc particles, to the composition of talc and to the inflammatory response. The purpose of this study was to evaluate the systemic and pulmonary response following intrapleural instillation of small particles talc (ST) and mixed particles talc (MT). One hundred rabbits received intrapleural instillation of talc as follows: fifty rabbits were instilled with ST (mean diameter=6,41 microns), and 50 rabbits with MT (mean diameter= 21,15 microns). As control (without talc instillation) were used 15 animals. We studied the pulmonary and systemic inflammatory response (total cell count and differential, levels of lactate dehydrogenase (LD), C-reactive protein (PCR), interleukin-8 (IL-8) and human vascular endothelial growth factor (VEGF) in serum and bronchoalveolar lavage (BAL). Histologic analysis of both lungs and quantitation of talc particles were done at 6, 24, 48, 72 and 96h. ST group showed higher pulmonary and systemic inflammatory response than did the MT group. PCR and IL-8 concentrations were higher in serum and BAL of ST group than the MT group. Many talc particles were observed in the pulmonary tissue of both talc groups, but without statistical significance. We also observed a predominance of cellular infiltrates (lymphomononuclear cells) in the lungs of ST group. The pulmonary inflammatory response (increased IL-8 in BAL) was earlier (24h) than the systemic inflammatory response (48 h). These observations suggest that the main organ in the systemic inflammatory acute response is lung. So, we recommend the clinical use of mixed talc without small particles to induce safety pleurodesis.

Made available in DSpace on 2014-08-20T13:32:50Z (GMT). No. of bitstreams: 1 tese_fabricio_rochedo_conceicao.pdf: 327058 bytes, checksum: 658bb226c85f41df4bb5329fd71ab1d7 (MD5) Previous issue date: 2005-05-23 / SUMMARY CONCEIÇÃO, FABRICIO ROCHEDO, Universidade Federal de Pelotas, may 2005. Production and Evaluation of Recombinant Subunit Vaccine Against Swine Enzootic Pneumonia. Advisor: Odir Antônio Dellagostin. Co-Advisor: Swine Enzootic Pneumonia (SEP), caused by bacterium Mycoplasma hyopneumoniae, is the most important respiratory disease in swine breeding. The commonly used vaccines to control this disease consist of bacterins, whose production cost is high and the efficiency is limited. The objective of this study was to develop and to evaluate a new alternative for controlling SEP, based on a recombinant subunit vaccine (rLTBR1) containing the R1 region of P97 adhesin of Mycoplasma hyopneumoniae (R1) fused to the B subunit of the heat-labile enterotoxin of Escherichia coli (LTB). rLTBR1 formed functional oligomers that presented high affinity to GM1 ganglioside. Mice inoculated with rLTBR1 (IN or IM) produced high levels of anti-R1 systemic and mucosal (sIgA) antibodies, which recognized the native P97. On the other hand, mice inoculated with the commercial bacterin did not produce anti-R1 antibodies. The administration route influenced the modulation of the immune response by LTB, showing that IM rLTBR1 induced Th2-biased immune responses and IN rLTBR1 induced Th1-biased immune responses. IN rLTBR1 also induced IFN-γ secretion by lymphocytes. The rLTB showed to be a powerful mucosal adjuvant, stimulating the production of anti-R1 IgA in trachea and bronchi from mice inoculated with rLTBR1 by parenteral route (IM). rLTBR1 may constitute a new strategy for preventing infection by Mycoplasma hyopneumoniae and may have potential for developing vaccines against other infectious diseases as well. Now a day, the efficacy of this vaccine is being evaluated in specific pathogen free swine. / A Pneumonia Enzoótica Suína (PES), causada pela bactéria Mycoplasma hyopneumoniae, é a doença respiratória mais importante na suinocultura. As vacinas convencionais utilizadas para controlar esta doença consistem de bacterinas, que apresentam custo de produção elevado e eficiência limitada. O objetivo deste estudo foi desenvolver e avaliar uma nova alternativa para controlar a PES, baseada em uma vacina de subunidade recombinante (rLTBR1) composta pela região R1 da adesina P97 de Mycoplasma hyopneumoniae (R1) fusionada a subunidade B da enterotoxina termolábil de Escherichia coli (LTB). rLTBR1 formou oligômeros funcionais que apresentaram alta afinidade pelo gangliosídeo GM1. Camundongos inoculados com rLTBR1 (I.M. ou I.N.) produziram altos níveis de anticorpos sistêmicos e de mucosa anti-R1, os quais reconheceram a P97 nativa. Por outro lado, os camundongos inoculados com a bacterina comercial não produziram anticorpos anti-R1. A rota de administração influenciou a modulação da resposta imune pela LTB, demonstrando que a rLTBR1 I.M. induziu uma resposta do tipo Th2 e a rLTBR1 I.N. do tipo Th1. rLTBR1 I.N. também induziu a secreção de IFN-γ por linfócitos. A rLTB demonstrou ser um potente adjuvante da imunidade de mucosa, estimulando a produção de IgA anti-R1 na traquéia e brônquios de camundongos inoculados com rLTBR1 através de rota parenteral (I.M.). A rLTBR1 pode constituir uma nova ferramenta para prevenir a infecção por M. hyopneumoniae, sendo que a estratégia utilizada pode ser aplicada no desenvolvimento de vacinas contra outras doenças infecciosas. Atualmente, a eficácia da rLTBR1 está sendo avaliada em suínos livres de patógenos específicos. rLTBR1; P97; LTB.

Treatment of lower respiratory tract infection (pneumonia and pleural infection) relies on the use of empirical broad spectrum antibiotics, primarily because reliable pathogen identification occurs infrequently. Another consequence of poor rates of pathogen identification is that our understanding of the microbiology of these infections is incomplete. This thesis addresses some of these issues by combining the acquisition of high quality lower respiratory tract samples, free from nasooropharyngeal contamination, with novel molecular microbiological techniques in an attempt to increase rates of pathogen identification. Four main areas are examined: (i) The role of so-called ‘atypical pneumonia’ bacteria in causing pleural infection. These pathogens have been previously identified in the pleural space infrequently and routine culture usually fails to isolate such bacteria. High sensitivity nested polymerase chain reaction (PCR) is a culture-independent technique which is used to undertake a systematic evaluation for these pathogens in pleural infection samples. (ii) The role of Pneumocystis jirovecii in pleural infection, either as a co-infecting pathogen or in monomicrobial infection. This fungus causes severe pneumonia, particularly in the immunosuppressed, but is increasingly recognised as a co-pathogen in community-acquired pneumonia, and is frequently isolated in the upper and lower respiratory tract in health. A high sensitivity real-time PCR assay is used to examine for this fungus. (iii) Ultra-deep sequencing of the 16S rRNA gene is used to perform a comprehensive microbial survey in samples taken from the multi-centre MIST2 study of pleural infection. The techniques employed allow analysis of polymicrobial samples and give very high taxonomic resolution, whilst incorporating methods to control for potential contamination. Further, these techniques provide confirmation of the results from the ‘atypical’ bacteria nested PCR study. (iv) Bedside ultrasound-guided percutaneous transthoracic needle aspiration (TNA) of consolidated lung is undertaken in patients with pneumonia, as part of the PIPAP study. An evaluation is undertaken of the efficacy and acceptability of TNA. Aspirate samples acquired are also processed using ultra-deep sequencing of the 16S rRNA gene. Other samples obtained as part of the PIPAP study, such as ‘control’ lung aspirates and ‘control’ pleural fluid samples, are similarly processed to enable calculation of sensitivity and specificity of the sequencing methodology.

<p>Uvod: Pneumonije su jedne od najče&scaron;ćih infekcija u dečjem uzrastu, a rendgenografija (RTG) grudnog ko&scaron;a se jo&scaron; uvek smatra metodom izbora za potvrđivanje dijagnoze. Cilj istraživanja je bio ispitivanje uloge ultrasonografije (US) pluća u dijagnostici i praćenju pneumonija kod dece. Materijal i metode: Istraživanje prospektivnog karaktera sprovedeno je u Institutu za zdravstvenu za&scaron;titu dece i omladine Vojvodine i obuhvatilo je 130 pacijenata uzrasta od 3 meseca do 18 godina kod kojih je zbog kliničke sumnje na pneumoniju bio načinjen RTG i US pregled pluća, u vremenskom razmaku do 24h. Kao referentni standard za utvrđivanje pouzdanosti US, RTG i auskultatornog pregleda u dijagnostici pneumonije kori&scaron;ćena je zavr&scaron;na dijagnoza pneumonije pri otpustu iz bolnice. US kriterijum za postavljanje dijagnoze pneumonije bio je nalaz subpleuralne konsolidacije plućnog parenhima. Deca sa US znacima pneumonije praćena su do potpune normalizacije US nalaza, a kod većine su kontrolni pregledi rađeni u vremenskim intervalima od 7-10 dana. Rezultati: Dijagnoza pneumonije je ustanovljena kod 105/130 (80,8%) pacijenata. US nalaz je ukazivao na pneumoniju kod 99/105 (senzitivnost 94,3%), a bio je negativan kod 25/25 pacijenata koji nisu imali pneumoniju (specifičnost 100%), dok je RTG bio pozitivan kod 98/105 (senzitivnost 93,3%), a negativan kod 23/25 pacijenata (specifičnost 92%). US je bila osetljivija od RTG metode u detekciji plućnih konsolidacija manjih od 15mm. Promene plućnog intersticijuma su registrovane ultrasonografijom kod 50/105 (47,62%), a rendgenografijom kod 21/105 (20%) pacijenata. Pleuralni izliv je registrovan ultrasonografijom kod 24/105 (22,86%), a rendgenografijom kod 14/105 (13,33%) pacijenata. Tokom kontrolnih pregleda utvrđeno je umereno do značajno slaganje US i kliničke procene toka bolesti (k=0,406-0,621). Kod pacijenata sa potpunom kliničkom, a nepotpunom US regresijom pneumonije, najče&scaron;će su bile zastupljene konsolidacije manje od 15mm. Prosečan broj dana do potpune regresije US nalaza je iznosio 16,3&plusmn;10,24 dana. Zaključak: Ultrasonografija pluća u dijagnostici pneumonija kod dece je pouzdana kao i rendgenografija. Ultrasonografija pluća treba da postane deo standardnog protokola dijagnostike pneumonije kod dece.</p> / <p>Background: Pneumonia is one of the most common infections in the pediatric population and chest radiography (CR) is still considered the method of choice to confirm the diagnosis. The aim of the study was to investigate the role of lung ultrasonography (LUS) in the diagnosis and follow-up of pneumonia in children. Methods: A prospective study was carried out in the Institute for Children and Youth Health Care of Vojvodina and it included 130 children with clinically suspected pneumonia, aged 3 months to 18 years, in whom CR and LUS were performed within 24h. The final diagnosis of pneumonia at discharge was used as a reference test to determine the reliability of LUS, CR and auscultatory findings in the diagnosis of pneumonia. A LUS finding of subpleural lung consolidation was considered a diagnostic sign for pneumonia. The children with LUS signs of pneumonia were followed up until complete resolution of the LUS findings. In most children, the follow-up LUS examinations were performed in time intervals of 7-10 days. Results: A final diagnosis of pneumonia was confirmed in 105/130 (80.8%) patients. LUS was positive in 99/105 patients (sensitivity 94.3%) and negative in 25/25 (specificity 100%), whereas CR was positive in 98/105 (sensitivity 93.3%) and negative in 23/25 (specificity 92%). LUS was superior to CR in the detection of lung consolidations less than 15mm. Interstitial lung changes were detected by LUS in 50/105 (47.62%) patients and by CR in 21/105 (20%). LUS was able to detect pleural effusion in 24/105 (22.86%) patients, whereas CR detected pleural effusion in 14/105 (13.33%). During the follow-ups, moderate to substantial agreement between LUS and clinical evaluation of the course of the disease was obtained (k=0.406-0.621). In children with complete clinical and incomplete US regression of pneumonia, consolidations less than 15 mm were the most prevalent finding. The average time period until complete resolution of the LUS findings was 16.3 &plusmn;10.24 days. Conclusions: Lung ultrasonography in the diagnosis of pneumonia in children is just as reliable as radiography. Lung ultrasonography should be included in the standard diagnostic protocol of pneumonia in children.</p>

En Amérique du Nord, Mycoplasma bovis est le plus pathogène des mycoplasmes retrouvés chez les bovins. Les principales maladies qu’on lui associe (maladies respiratoires, mammites, arthrites septiques et otites moyennes et/ou internes) constituent un défi à l’industrie laitière à cause de la difficulté à les traiter et à les prévenir par une vaccination. L’objectif principal de ce projet était d’étudier l’excrétion nasale et la réponse sérologique à M. bovis chez les génisses de remplacement, entre la naissance et 7 mois d’âge, dans 4 troupeaux laitiers au Québec. Quatre-vingt-trois paires mère/génisse provenant de 4 cohortes de bovins laitiers étaient prélevées mensuellement (génisses : 0 à 7 mois ; mères : 0, 1 et 5 mois après vêlage). Écouvillons nasaux et échantillons de lait étaient analysés par culture bactériologique et par immunofluorescence indirecte. Les anticorps circulants étaient détectés par le test ELISA. À la naissance, la prévalence sérologique des génisses était supérieure à celle des mères (P = 0,01). La transmission de M. bovis aux génisses par le lait et par l’excrétion nasale des mères était faible. L’âge moyen (jour) d’une génisse à sa 1ère excrétion nasale et sa 1ère séroconversion à M. bovis était loin de la période néonatale: 77,5 ± 11,2 (n = 22) et 96,8 ± 7,4 (n = 36) respectivement. Conclusion, les vaches adultes n’ont constitué qu’une voie mineure de transmission de M. bovis aux génisses, la principale voie de transmission était fort probablement le contact direct ou indirect avec d’autres génisses excrétrices nasales de M. bovis. / In North America, Mycoplasma bovis is the most pathogenic mycoplasma found in cattle. The main diseases associated with it (respiratory disease, mastitis, septic arthritis and otitis median and/or internal) are a challenge to the dairy industry because of the difficulty to treat them and to prevent them by vaccination. The principal objective of this project was to study nasal shedding and serological response to M. bovis in replacement heifers, between birth and 7 months of age, in four dairy herds in Quebec. Eighty three pairs cow/heifer in 4 cohorts of dairy cattle were sampled monthly (heifers: 0 to 7 months; cows: 0, 1 and 5 months after calving). Nasal swabs and milk samples were analyzed by bacteriological culture and by indirect immunofluorescence. Circulating antibodies were detected by ELISA test. At birth, the serologic prevalence of heifers was significantly higher than the serologic prevalence of cows (P = 0,01). Transmission of M. bovis to heifers in milk and nasal shedding from cows was low. The average age (days) of a heifer for first nasal shedding and first seroconversion to M. bovis was far from the neonatal period: 77,5 ± 11,2 days (n = 22) and 96,8 ± 7,4 days (n = 36) respectively. Conclusion, cows were only a minor route of transmission of M. bovis to heifers, the main route of transmission was most likely the direct or indirect contact with other heifers shedding M. bovis in their upper respiratory tract.

Antecedentes: La neumonía es una infección grave común en la infancia y principal causa de muerte en niños menores de 5 años. Se sabe poco sobre escalas que evalúen el riesgo de muerte por neumonía. Objetivos: Establecer qué escala tiene mejor desempeño como predictor de muerte por neumonía adquirida en la comunidad (NAC) en niños menores de cinco años. Métodos: Se realizo un estudio observacional, retrospectivo, analítico con un diseño de precisión diagnóstica en una cohorte de registros clínicos de pacientes con NAC entre 2013 y 2015 en las primeras 24 horas de ingreso al hospital. El desempeño de las tres escalas se evaluó comparando el área bajo la curva (ABC) como medida de capacidad discriminativa. Resultados: La escala PIRO modificada (Predisposition, Insult, Response and Organic dysfunction) tiene mayor capacidad discriminatoria con un ABC de 0,93 (IC del 95%: 0,89 a 0,96), siendo la mejor de las tres escalas evaluados. En segundo lugar, la escala RISC (Respiratory Index of Severity in Children) con ABC 0,83 (IC 95%: 0.79-0.87) y, finalmente, la escala PRESS (Pediatric Respiratory Severity Score) ABC 0.67 (IC 95% 0.61 - 0.74). Conclusión: Las escalas PIROm y RISC son buenos predictores de muerte en niños menores de 59 meses, basados en criterios clínicos, radiológicos y laboratoriales. La primera escala podría ser utilizada en centros de salud de mayor complejidad. La segunda escala netamente clínica podría ser utilizada en centros de atención primaria de salud. Se sugiere realizar más estudios en poblaciones con diversas características clínicas, demográficas y ambientales. / Background: Pneumonia is a common serious infection in childhood, being the major cause of death in children under 5 years. Little is kwon about clinical scales predicting risk of death owing to pneumonia Objectives: Establish which scale has better performance as a predictor of death due to community-acquired pneumonia (CAP) in children under five years. Methods: An observational, retrospective, analytical study with a diagnostic precision design was conducted in a cohort of clinical records of patients with CAP between 2013 and 2015 that were review in the first 24 hours of admission to the hospital. The performance of the three scales were evaluated by the comparison of the area under the curve (AUC) as a measure of discriminative capacity. Results: The PIRO modified scale (Predisposition, Insult, Response and Organic dysfunction) has greater discrimination capacity AUC of 0.93 (95% CI 0.89 - 0.96) being the best of the three evaluated. Secondly, the RISC scale (Respiratory Severity Index in children) with AUC 0.83 (95% CI: 0.79-0.87) and, finally, the PRESS scale (Pediatric Respiratory Severity Score) AUC 0.67 (95% CI 0.61 - 0.74). Conclusion: The PIROm and RISC scales are good predictors of death in children under 59 months, based on clinical, radiological and laboratory criteria. The first scale could be used in healthcare centers of higher complexity. The second scale purely clinical could be used in centers of primary health care attention. It is suggested to carry out more studies in diverse populations with different clinical, demographical and environmental characteristics. / Tesis