Les pneumonies sont la première cause de mortalité par maladie infectieuse dans le monde chez les enfants. Les objectifs étaient d'identifier les causes microbiologiques des pneumonies communautaires chez les enfants de moins de 5 ans dans les pays émergents et en développement et les déterminants associés à leur sévérité en termes d'hypoxémie à l'admission et de mortalité. Une étude cas-témoins multicentrique hospitalière a été menée par le réseau GABRIEL dans 9 sites des pays suivants : Cambodge, Chine, Haïti, Inde (2 sites), Madagascar, Mali, Mongolie et Paraguay. Les cas étaient des enfants hospitalisés, âgés de 2 à 60 mois et atteints de pneumonie radiologiquement confirmée ; un témoin par cas du même centre, sans signe évocateur de pneumonie était recherché. Un appariement fréquentiste sur la période et la classe d'âge était effectué. Des prélèvements respiratoires ont été réalisés chez tous les sujets pour identifier 19 virus, 5 bactéries et les sérotypes de Streptococcus pneumoniae par biologie moléculaire. Pour les cas, des prélèvements supplémentaires de sang et de liquide pleural étaient effectués. Les étiologies des pneumonies ont été estimées par le calcul de la fraction attribuable populationnelle après régression logistique multivariée. Les facteurs associés à l'hypoxémie à l'admission - déterminés chez les patients atteints de pneumonie - ont été identifiés par régression logistique multivariée ; les facteurs associés à la mortalité hospitalière à 14 jours ont été quantifiés par modèle de Cox bivarié. Parmi les 888 cas et 870 témoins analysés, les agents causaux des pneumonies après analyse multivariée étaient par ordre décroissant de fréquence : S. pneumoniae, respiratory syncytial virus (RSV), rhinovirus, human metapneumovirus (hMPV), parainfluenza virus 1, 3 et 4, influenzavirus A et B et Mycoplasma pneumoniae. La fraction attribuable ajustée était de 42,2% (intervalle de confiance [IC] à 95% : 35,5-48,2%) pour S. pneumoniae, de 18,2% (IC à 95% : 17,4-19,0%) pour RSV et de 11,2% (IC à 95% : 7,5-14,7%) pour rhinovirus. Une importante hétérogénéité des étiologies entre pays a été identifiée. Parmi les 405 cas de pneumonie analysés pour l'étude de la gravité, 17,3% étaient hypoxémiques. La détection d'hMPV ou de RSV au niveau respiratoire était indépendamment associée à un risque accru d'hypoxémie (odds ratio ajusté [ORa]=2,4 ; IC à 95% : 1,0-5,8 et ORa=2,5 ; IC à 95% : 1,1-5,3, respectivement). La détection de S. pneumoniae dans le sang (hazard ratio brut [HRb]=4,6 ; IC95% : 1,5-14,0), un dosage de procalcitonine ≥50 ng/ml (HRb=22,4 ; IC à 95% : 7,3-68,5) et l'hypoxémie à l'admission (HRb=4,8, IC à 95% : 1.6-14.4) étaient prédictifs de surmortalité hospitalière ; ces associations subsistaient après ajustement sur l'âge, la période, le centre, la séropositivité HIV ou le statut nutritionnel. La majorité des pneumonies chez les enfants de moins de 5 ans dans les pays en développement peut être attribuée à S. pneumoniae, RSV, rhinovirus et hMPV. Les pneumonies hypoxémiantes chez les enfants sont liées à hMPV et RSV alors que les pneumonies liées à S. pneumoniae sont associées à un risque accru de décès. Ces résultats permettent d'identifier des priorités de prévention vaccinales et non-vaccinales / Pneumonia is the leading cause of death from infectious diseases in children worldwide. The objectives were to identify the etiologies of community-acquired pneumonia in children under 5 years in emerging and developing countries and the determinants associated with severity in terms of hypoxemia at admission and mortality. A hospital-based multicenter casecontrol study was conducted at 9 sites in the following countries: Cambodia, China, Haiti, India (2 sites), Madagascar, Mali, Mongolia and Paraguay. Cases were hospitalized children aged between 2 and 60 months, with radiologically confirmed pneumonia; a control was a patient from the same center, without any sign suggesting pneumonia. A frequentist matching by period and age category was made. Respiratory samples were taken from all subjects to identify 19 viruses, 5 bacteria and Streptococcus pneumoniae serotypes by molecular biology. For cases only, additional blood samples and pleural fluid were performed. The etiologies of pneumonia were estimated by calculating the population-attributable fraction after multivariate logistic regression. The factors associated with hypoxemia at admission were identified in patients with pneumonia by multivariate logistic regression; factors associated with 14-day in-hospital mortality were quantified by bivariate Cox model. Among the 888 cases and 870 controls analyzed, the causative agents of pneumonia after multivariate analysis migth be: Streptococcus pneumoniae, respiratory syncytial virus (RSV), rhinovirus, human metapneumovirus (hMPV), parainfluenza virus 1, 3 and 4, influenzavirus A and B, and Mycoplasma pneumoniae. The adjusted attributable fraction was 42.2% (95% confidence interval [CI]: 35.5-48.2%) for S. pneumoniae, 18.2% (95% CI: 17.4-19.0%) for RSV and 11.2% (95% CI: 7.5-14.7%) for rhinovirus. A significant heterogeneity in etiologies between countries was identified. Among the 405 pneumonia cases analyzed for the study of gravity, 17.3% were hypoxemic. Detection of hMPV or RSV from respiratory samples were independently associated with an increased risk of hypoxemia (adjusted odds ratio [aOR]=2.4, 95% CI: 1.0-5.8; aOR=2.5, 95% CI: 1.1-5.3, respectively). Detection of S. pneumoniae from blood (crude hazard ratio [cHR]=4.6, 95% CI: 1.5- 14.0), procalcitonin ≥50 ng/ml (cHR=22.4, 95 %: 7.3-68.5) and hypoxemia (cHR=4.8, 95% CI: 1.6- 14.4) were predictive of higher hospital mortality; these associations were consistent after adjusting for age, period, center, HIV or nutritional status. The majority of pneumonia in children under 5 years of age in developing countries might be attributable to S. pneumoniae, RSV, rhinovirus and hMPV. Hypoxemic pneumonia in children were related to RSV and hMPV infection while S. pneumoniae-related pneumonia was associated with an increased risk of death. These findings might guide future vaccinal or non vaccinal policies

Twenty publications are submitted. All deal with the issues of control of two ends of the spectrum of immune-mediated respiratory disorders in children, namely atopic (asthma and allergic rhinitis) and HIV-related lung disease. This submission summarises the research by the author into this spectrum of lung diseases of children in South Africa, highlighting the diversity of conditions that are not only clinically important, but also common. Understanding of all conditions is required to improve the health of children in this region. Management of chronic conditions requires two major end points - adequate and timely diagnosis and - management to control the condition. The author has a passion for improving the quality of life of children and firmly believes that the research findings will, and have, led to transformation in management of both these common disorders. This document follows the progression of the authors research work and highlights how interesting and important is the scope of two disorders which could be thought to have a central origin, namely in the T-cell. T-cells form the basis of cellular immunity and an excess of T-helper 2 cell activity promotes atopy, whilst the human immunodeficiency (HI) virus infects T-helper cells and promotes cellular immune deficiency and its attendant clinical disorders. The author’s research work is not based on the immunological basis of these conditions but does deal with the clinical implications and especially aspects relating to control of these two extremes of a clinical spectrum of disorders. To take the clarity of two diseases at the end of a spectrum to its natural conclusion these extremes are defined in aetiology or pathophysiological differences (excess versus suppression of the immune system), occurring in the affluent and poor alike versus just the poor, control being required to improve quality of life versus to save lives and finally that management requires anti-inflammatory therapy versus antibiotic and anti-infective therapy. For the eight publications based on atopic respiratory disease in children the themes are firstly that children with asthma and chronic rhinitis are diagnosed late, that most individuals with these conditions are not well controlled and finally that the reasons for lack of control are becoming obvious. For the first time, the significant lack of asthma and allergic rhinitis control in South Africa is documented. These studies suggest that, like surveys from the rest of the world, asthma control is seriously under-estimated and neglected in all asthmatics in South Africa, in both the privileged and the under-privileged. The research also defines reasons for poor asthma and allergic rhinitis control in this region. As in many studies published from around the world it is now evident that poor asthma and allergic rhinitis control cannot be blamed on any one source. A multitude of reasons underlie this phenomenon and each of the subsequent papers in this section illustrates attempts at defining these principles. The three most important reasons for poor control are probably that most asthmatics are managed in the wrong hands (by doctors who don’t understand adequate control and who aren’t empowered to use the correct therapy), that control may actually be a pipe dream and practically difficult to do or even impossible to achieve and lastly that the allergic basis of asthma is over emphasised and may not in fact determine all asthma. The subsequent papers summarise research work in the field of HV infection in children and exposes the opposite end of a spectrum of Paediatric respiratory disease and highlight research into the conditions common in HIV-infected children. Eleven papers are presented. For the diseases associated with the HI virus the major complications of inadequate diagnosis and prevention in children are acute pneumonia (especially severe pneumonia) and bronchiectasis. Bronchiolitis is not common in HIV infected children, despite epidemics of this condition in non-infected children. Passive smoking does not aggrevate or worsen disease progression in children. The complications of HIV related diseases in children require the same principles of adequate diagnosis and control as would apply to the chronic atopic conditions. Once the author delved into the disorders at the other end of the clinical spectrum, namely those associated with immune deficiency secondary to HIVinfection he faced the question of a possible relationship between the conditions. One submission explores that relationship. This research has a unique perspective, conferred by the fact that these two conditions do not occur to the same extent anywhere else in the world. Atopic respiratory conditions and HIV-related lung diseases occur side by side in abundance in this region. This perspective has created a clarity for research to address the two most important aims in clinical medicine, namely to diagnose correctly and then to manage the condition so that control is achieved. These must be universal principles of the successful practice of medicine. / Thesis (DSc)--University of Pretoria, 2013. / gm2013 / Paediatrics and Child Health / unrestricted

En réanimation, les facteurs de risque d’infection à bactéries résistantes sont nombreux et il est nécessaire d’instaurer une antibiothérapie rapide et adéquate. Cela conduit donc souvent au choix empirique d’antibiotiques à large spectre. Ce travail de thèse regroupant quatre études porte sur les éléments de ce choix. Dans la première étude, les critères de "pneumopathie associée aux soins" sont discutés. Dans la seconde, il est rapporté que le traitement antibiotique prescrit au début du séjour en réanimation est associé à l’acquisition de Pseudomonas aeruginosa. Dans le diagnostic d’une pneumopathie acquise sous ventilation, la troisième étude décrit une technique rapide d’antibiogramme permettant une désescalade antibiotique plus précoce. La néphrotoxicité des aminoglycosides dans le traitement empirique des patients en sepsis sévère est présentée dans la dernière étude. Ces travaux participent à la bonne gestion des antibiotiques à la phase empirique du traitement des infections sévères en réanimation. / Intensive care units (ICU) are a niche for risk factors of infection due to multidrug resistant bacteria. ICU patients are in a need for a rapid and adequate antibiotic therapy. This leads ICU physicians to use empirical broad spectrum antibiotics. This thesis comprises four studies which focus on the empirical step of the treatment. In the first study, the criteria for "health-care-associated pneumonia" are discussed. The second shows that the antibiotic selection pressure administered early during the ICU stay could lead to Pseudomonas aeruginosa acquisition. In the third study, a rapid direct specimen testing method was assessed for ventilator-associated pneumonia diagnosis in order to hasten antibiotic de-escalation. Finally, a review on aminoglycosides’ nephrotoxicity in the severe sepsis setting represents the fourth study. These studies bring a loop forward into the understanding of the antibiotic stewardship of patients with severe sepsis, with particular focus on the empirical antibiotic treatment.

Les infections respiratoires et plus particulièrement la pneumonie représentent la première cause de mortalité infantile dans le monde. L’essor des technologies de diagnostic moléculaire a permis de mettre en évidence une étiologie très hétérogène des infections respiratoires ainsi qu’un taux élevé de co-infection virale et bactérienne dont l’impact clinique reste difficile à évaluer. La recherche translationnelle menée au cours de ce projet de thèse avait pour objectif de décrire l’étiologie des infections respiratoires ainsi que l’impact des co-infections sur la modulation de la réponse immunitaire innée. Nous avons développé un modèle d’étude in-vitro d’infection successive de cellules présentatrice d’antigènes (CPA) humaines par le virus Influenza (IAV) et Streptococcus pneumoniae (SP) et étudié la modulation de la réponse inflammatoire. Les résultats obtenus démontrent que la co-infection des CPA par ces deux pathogènes majeurs de la pneumonie impacte fortement sur leur viabilité et induit une dérégulation importante de la réponse inflammatoire. Au cours de la co-infection, la chémokine pro-inflammatoire IP-10 est exprimée de manière synergique suggérant un rôle jusqu’à présent non décrit de cette chémokine dans la pathogénèse de la pneumonie. Nous avons également démontré que les micro-ARNs (dont le miR-200a-3p) participent activement à la régulation de la réponse inflammatoire, en ciblant des régulateurs de la voie de signalisation JAK-STAT (SOCS-6) et indirectement la voie de synthèse d’IP-10. Récemment, nous avons évalué la réponse inflammatoire d’enfants âgés de moins de 5 ans hospitalisés pour une pneumonie, en partenariat avec les équipes médicales et scientifiques du Paraguay via le réseau GABRIEL. Ce volet d’étude confirme 1) une étiologie variée de la pneumonie chez l’enfant et 2) un taux d’IP-10 sérique significativement plus élevé chez les enfants co-infectés et présentant une pneumonie très sévère. / Respiratory infections, especially pneumonia are the leading cause of death among children under 5 years-old worldwide. Advances in molecular diagnostic have highlighted heterogeneous etiologies of respiratory infections with a high proportion of viral and bacterial co-infections whose clinical impact remain difficult to assess. The translational research conducted during this thesis aimed to describe the etiology of respiratory infections and the impact of viral and bacterial co-infections on the innate immunity.We have developed an in-vitro study model of sequential infection of antigen presenting cells (APC) by the human influenza virus and Streptococcus pneumoniae and studied the modulation of the inflammatory response. The results show that APC co-infection by those two major pathogens of pneumonia strongly impacts cells viability and induces a significant deregulation of the inflammatory response. During co-infection, pro-inflammatory chemokine IP-10 is synergistically expressed suggesting a role so far undescribed for this chemokine in the pathogenesis of pneumonia. We also demonstrated that micro-RNAs (including miR-200a-3p) actively participate in the regulation of the inflammatory response by targeting the signaling pathway regulators JAK-STAT (SOCS-6) and indirectly IP-10 signalling pathway.Recently, we evaluated the inflammatory response of children aged under 5 hospitalized for pneumonia, in partnership with medical and scientific teams of Paraguay involved in the GABRIEL network. This study confirmed 1) a varied etiology of childhood pneumonia and 2) a significant elevated IP-10 serum level among children with very severe pneumonia caused by mixed viral and bacterial co-infections.

Les deux formes d'inflammation pulmonaire en réanimation sont la pneumonie et le syndrome de détresse respiratoire aiguë (SDRA). Nous avons conçu un test diagnostique rapide basé sur l'autofluorescence des neutrophiles alvéolaires. S'appuyant sur une étude expérimentale, puis sur une étude clinique randomisée, nous avons montré que les sondes d'intubation avec ballonnets coniques diminuaient les micro-inhalations sans prévenir l'incidence des pneumonies post-opératoire. Une grande variabilité des pressions des ballonnets coniques pose la question de leur effet délétère. La thérapie cellulaire basée sur les cellules souches mésenchymateuses (CSM) est prometteuse. L'étude des effets thérapeutiques des vésicules extracellulaires issues de CSM (VE-CSM) constitue un nouvel axe de recherche. Dans 2 modèles murins de SDRA, puis dans un modèle de poumons humains ex vivo, nous avons démontré des effets thérapeutiques des VE-CSM. Nous avons ensuite étudié les lymphocytes T régulateurs (Treg) pulmonaires et systémiques dans le SDRA. Cette étude a montré un déficit quantitatif plutôt que fonctionnel de la population Treg pulmonaire dans le SDRA, avec une cinétique évoquant un recrutement des Treg circulants vers le compartiment pulmonaire au cours de la maladie. En conclusion, nos travaux ont développé de nouvelles stratégies diagnostiques et préventives des pneumonies de réanimation, afin de réduire leur impact en termes de morbi-mortalité. Les bénéfices thérapeutiques des CSM et des VE-CSM dans le SDRA expérimental, ainsi que l'altération du phénotype Treg observé chez nos patients, ouvrent de nouveaux champs de recherche vers le développement d'immunothérapies innovantes. / Pneumonia and acute respiratory distress syndrome (ARDS) are two facets of severe acute lunginflammation, often met in intensive care unit (ICU). Rapid diagnosis of pneumonia remains essential inorder to optimize their management. We worked on setting up a quick test diagnosis based on theintensity of alveolar neutrophils autofluorescence. The validation of this test in a multicenter cohort isunderway. Preventing microaspiration across the cuff remains a priority to prevent pneumonia inmechanically ventilated patients. Based on the results of an ex vivo study followed by a clinicalrandomized trial, we showed that tapered-cuff endotracheal tube prevented microaspiration in the exvivo model, without lowering intraoperative microaspirations and postoperative pneumonia rate aftermajor vascular surgery. Both studies yielded similar results concerning the higher variation of cuffpressureover time, which leads to the question of their safety of use in terms of potential resultingtracheal wall ischemia.Pneumonia represents 80% of the cause of ARDS, which can be viewed as lung uncontrolledinflammatory response. Cell-based therapy using mesenchymal stem cells (MSC) is a growing field ofresearch in ARDS therapy. Despite numerous beneficial effects in ARDS, their capacity of self-renewalpoints them out as a potential cancer inducer in the mid-long term. In this context, evaluating thetherapeutic effects of extracellular vesicles-released from MSC (EV-MSC) represents a novel approach.We showed therapeutic effects of EC-CSM in two murine model of ARDS induced by endotoxin or liveEscherichia coli bacteria, and in another ex vivo human lung preparation.We then focused our research on temporal and compartmental dynamics of regulatory T cells(Treg) phenotypes in ARDS patients. This prospective observational clinical study showed that Early ARDSwas characterized with an alveolar compartment fully polarized towards pro-inflammatory state andneutrophils chemotaxis. In lung compartment, and compared to control patients, ARDS patients showeda quantitative Tregs deficiency, which partially recovered over time, while activation markers wereoverexpressed in both Tregs and effectors T cells (Teff). Conversely, patients with ARDS had a higherproportion of systemic Tregs compared to controls. Significant increased proportion in circulating Th1,Th22, and ILC1 subsets, and decreased proportion in ILC3 subsets were also found in ARDS patientscompared to controls.In conclusion, we developed novel strategies to diagnose and prevent pneumonia in ICU, whichremains essential to improve patients’ outcomes. Therapeutic effects of MSC and EV-MSC, as well asTreg phenotype alterations pave the way for development of novel immunoregulatory therapies.

La grippe est une infection respiratoire aiguë, due au virus Influenza, qui touche en moyenne chaque hiver 2,5 millions de personnes. C'est un enjeu de santé publique majeur par son impact économique et en santé humaine. Les traitements actuellement disponibles contre le virus Influenza repose sur des antiviraux ciblant la neuraminidase (inhibiteur de la neuraminidase). Jusqu'en 2007 moins de 5% des souches de virus Influenza circulantes dans le monde étaient résistantes à ces INA. Contre toute attente, l'hiver 2007/2008 a été marqué par l'émergence simultanée d'une nouvelle souche apparentée au virus A/Brisbane/59/2007(H1N1) et d'une augmentation massives des résistances à l'Oseltamivir. Nous avons caractérisés les propriétés enzymatiques des souches sensibles et résistantes isolées dans la communauté au cours des saisons 2007/2008, 2008/2009 pour les comparer à un panel de souches de référence des virus A(H1N1). Les résultats obtenus soulignent la particularité des propriétés enzymatiques de la NA de A/Brisbane/59/2007(H1N1) et le rôle de la balance HA-NA dans la diffusion mondiale de cette souche résistante en l'absence de pression de sélection La pandémie de 2009 au virus A(H1N1)pdm09 a été l'occasion de décrire le rôle de l'infection respiratoire basse, virale isolée ou dans le cadre d'une co-infection bactérienne, dans les patients décédés d'un syndrome de détresse respiratoire. La forte proportion de pneumonies virales observées dans les études épidémiologiques réalisées au cours de la pandémie de 2009/2010 et de la saison 2010/2011 suggère la présence de facteurs de virulence permettant au virus A(H1N1)pdm09 de se lier aux récepteurs présents au niveau de l'appareil respiratoire bas. Nous avons étudié l'impact du polymorphisme en position 222 de la HA du virus A(H1N1)pdm09 sur les propriétés de liaison de la HA à son récepteur, sur la balance HA-NA et, in fine, sur le phénotype des virus in vitro et in vivo. Nos résultats montrent que les substitutions D222G, D222E et D222N de la HA du virus A(H1N1)pdm09 favorisent la liaison aux acides sialiques présents au niveau de l'alvéole pulmonaire. Cette propriété pourrait expliquer la plus forte pathogénicité pulmonaire de ce virus. Par ailleurs nos résultats montrent également une association entre l'équilibre de la balance HA-NA et le profil de réplication de ces souches in vitro / Influenza is responsible of 2,5 million cased of respiratory infection, each winter, in France. It is a main human health threat and a main public health concern. The current treatment of flu relies on antiviral drug targeting viral proteins that can induce the appearance of resistant virus. Until 2007, less than 5% of all circulating Influenza strains were resistant to neuraminidase inhibitors. Against all odds, Oseltamivir resistant A/Brisbane/59/2007(H1N1) emerged and spread during 2007/2008 and 2008/2009 season. To understand the driving force of this emergence we tested clinical strains from 2007 to 2011 for Oseltamivir and Zanamivir resistance, sequenced their HA and NA gene, and compared their NA enzymatic properties with A(H1N1) reference strain from 1977 to 2007. Our results showed that A/Brisbane/59/2007 displayed a high affinity compare with NA of previous A(H1N1) reference strains. Moreover these results suggested that HA-NA balance underlie the worldwide emergence of the Oseltamivir resistance without any selection pressure. The A(H1N1)pdm09 pandemic highlighted the importance of lower tract respiratory infection in the severe influenza case. The high proportion of viral pneumonia observed during the 2009 pandemic and the following season suggest that A(H1N1)pdm harbored a virulence factor that allowed the virus replication in the lower respiratory tracts. We studied the effect of HA 222 polymorphism on HA properties, HA-NA balance and in vitro and in vivo Influenza phenotype. Our results demonstrated that G222, E222 or N222 HA mutation increased the binding of A(H1N1)pdm09 mutation to the lower respiratory tract receptor. This may explain the A(H1N1)pdm09 increase pathogenicity. Moreover our results show than an optimal HA-NA balance is link to an efficient replication profile in vitro

L'émergence de bactéries résistantes à plusieurs classes d'antibiotiques rend difficile le traitement des pneumonies nosocomiales. Notre objectif était d'évaluer de nouvelles stratégies thérapeutiques et hypothèses physiopathologiques dans des modèles murins de pneumonie.Dans un premier modèle de pneumonie aigue létale à A. baumannii chez le rat, nous avons comparé la virulence de 2 souches nosocomiales, l'une sensible (ABCS) et l'autre résistante (ABCR) à la colistine. Nous avons montré une diminution de la mortalité, du compte bactérien pulmonaire, de l'incidence des bactériémies et des lésions histologiques pulmonaires chez les animaux infectés avec ABCR, ceci confirmant la baisse de virulence associée à l'acquisition de la résistance à la colistine. Dans un second travail, nous avons développé un modèle de pneumonie chronique à P. aeruginosa chez le rat et montré que des aérosols de squalamine permettaient une diminution de la charge bactérienne pulmonaire et du nombre de lésions histologiques de pneumonie. Au cours d'un troisième travail, nous avons évalué l'effet inhibiteur du quorum sensing d'une lactonase in vitro et dans un modèle de pneumonie aigue létale à P. aeruginosa chez le rat. Nous avons constaté une diminution de l'activation de gènes de virulence et de la synthèse de biofilm bactérien in vitro. Ceci était associé à une diminution de la mortalité de 75 à 20 % chez les animaux traités.ConclusionsCe travail de thèse nous a permis de montrer le potentiel thérapeutique de 2 molécules dans des pneumonies à P. aeruginosa et d'illustrer la perte de virulence associée à la résistance à la colistine dans une souche clinique d'A. baumannii. / The emergence multi-drug resistant bacteria hardens the treatment of nosocomial pneumonia. Our objective was to evaluate new therapeutic strategies and pathophysiological hypotheses in murine models of pneumonia.In a first model of acute lethal pneumonia with A. baumannii in rats, we compared the virulence of two hospital strains, one susceptible (ABCS) and the other resistant (ABCR) to colistin. We showed a reduction in mortality, pulmonary bacterial count, incidence of bacteremia and pulmonary histological lesions in animals infected with ABCR. This confirms the impaired virulence associated with the acquisition of resistance to colistin. In a second study, we developed a model of chronic pneumonia with P. aeruginosa in rats and showed thataerosols of squalamine permitted a reduction in pulmonary bacterial load and the number of histological lesions of pneumonia. In a third study, we evaluated the quorum quenching effects of a lactonase in vitro and in a model of acute lethal P. aeruginosa pneumonia in rats. We found a decrease in virulence gene activation and bacterial biofilm synthesis in vitro. This was associated with a decreased mortality from 75 to 20% in the treated animals.ConclusionsIn this work, we described the therapeutic potential of 2 molecules in P. aeruginosa pneumonia and illustratesd the loss of virulence associated with resistance to colistin in a clinical strain of A. baumannii.

Streptococcus pneumoniae é o principal causador da pneumonia bacteriana. As vacinas atualmente disponíveis contêm polissacarídeo capsular conjugado ou não com proteínas carreadoras. No entanto, elas apresentam elevado custo ou proteção reduzida nos grupos de risco (crianças abaixo de 5 anos de idade e idosos). Proteínas de superfície de S. pneumoniae, como a PsaA e PspA, são consideradas fortes candidatas vacinais. Com o objetivo de se desenvolver uma vacina de ampla cobertura e baixo custo contra pneumococos, os genes psaA e pspA foram clonados em vetores de expressão em E. coli, pAE e pET e as proteínas expressas foram purificadas por cromatografias de afinidade e de troca aniônica. O rendimento de proteína recombinante obtido com a construção baseada em pET foi 3 vezes maior que o obtido com pAE. Condições de cultivo foram estabelecidas utilizando meio definido com indução por IPTG e/ou por lactose. As cepas recombinantes estão adequadas para serem usadas em estudos para escalonamento da produção em biorreatores. / Streptococcus pneumoniae is the main causative agent of bacterial pneumonia. The current vaccines available contain capsular polysaccharide conjugated or not with carrier proteins. However these are either too expensive or do not protect the high-risk groups. Surface proteins of S. pneumoniae, such as PsaA and PspA, are considered strong vaccine candidates. With the aim of developing a broad-coverage and low-cost vaccine against pneumococcus, the psaA and pspA genes were cloned in E. coli expression vectors, pAE and pET and the expressed proteins were purified through affinity and anion exchange chromatography. The yield of the recombinant protein obtained with the construction based in pET was 3-fold higher than that obtained with pAE. Culture conditions were established using defined media with IPTG and/or lactose induction. The recombinant strains are now ready to undergo studies for scale-up of production in bioreactors.

Ziel dieser Publikation soll es sein, der/m Behandler/in fundiertes Grundwissen bzgl. des Ölziehens zu vermitteln. Darüber hinaus wird die aktuelle Studienlage dargestellt, es werden Trends aufgezeigt und das Risiko der Lipidpneumonie erläutert. Die Autoren kommen zu dem Ergebnis, dass es derzeit geringe Evidenz für einen positiven Nutzen des Ölziehens gibt, sodass weiterführende Studien auf diesem Gebiet notwendig sind. Über das sehr geringe Risiko einer Lipidpneumonie bei nicht korrekter Anwendung sollten die Patientinnen und Patienten aufgeklärt werden. / This publication should provide the practitioner with sound basic knowledge about oil pulling. In addition, the authors present the current study situation, show trends and explain the risk of lipoid pneumonia. The limited evidence to date from clinical trials suggest that oil pulling may have beneficial effects, therefore more studies are necessary to prove beneficial effects on orodental hygiene. Furthermore, patients should be informed about the risk of lipoid pneumonia if used incorrectly.

Introducción: La neumonía es la principal causa de muerte en niños menores de 5 años a nivel global y el 90% de sus casos se registran en países en vías de desarrollo. Determinar los factores asociados (FA) a casos severos (CS) y casos fatales (CF) de neumonía adquirida en la comunidad (NAC) en niños menores de cinco años atendidos en el INSN entre los años 2013-2015 en lima Perú. Materiales y Métodos: Se realizó un estudio observacional, retrospectivo, analítico de casos y controles en pacientes atendidos en el INSN entre los años 2013 al 2015; el estudio se dividió en 2 sub-estudios, para determinar los factores asociados a casos fatales tenemos el denominado sub-estudio “A” y el denominado sub-estudio “B” para determinar los factores asociados a casos severos. Resultados: Los factores asociados a casos fatales en niños entre 1 a 59 meses con NAC atendidos en el INSN fueron: Tener una edad entre 1 a 5 meses (ORa=3.61, IC: 1.1-11.76), desnutrición aguda (ORa=3.74, IC: 1.1-12.63), tener consolidado multilobar (ORa=3.1, IC: 1.006-9.5) y tener consolidado en parche (ORa=0.17, IC: 0.057-0.5). Los factores asociados a casos severos fueron: Tener una edad entre 1 a 5 meses (ORa=0.28, IC: 0.18-0.55), ser pretérmino (ORa= 0.36, IC: 0.17-0.77), tener diarrea (ORa=0.36, IC: 0.15-0.87), que el cuidador tenga como grado de instrucción la secundaria (ORa= 2.43, IC: 1.36-4.35), negarse a comer (ORa= 3.84, IC: 1.14-12.84) y tener asma (ORa=10.66, IC: 1.11-102.3). Conclusiones: Los factores asociados a mortalidad identificados son: edad entre 1 a 5 meses, tener desnutrición aguda, tener consolidado multilobar. Los factores de riesgo para severidad son: grado de instrucción del cuidador secundaria, negarse a comer y tener asma. / Introduction: Pneumonia is the leading cause of death in children under 5 years of age globally and 90% of its cases are registered in developing countries. To determine the factors associated (AF) to severe cases (SC) and fatal cases (CF) of community-acquired pneumonia (CAP) in children under five years of age treated at the INSN between the years 2013-2015 in Lima, Peru. Materials and Methods: An observational, retrospective, analytical case-control study was carried out in patients treated at the INSN between 2013 and 2015; The study was divided into 2 sub-studies, to determine the factors associated with fatal cases we have the so-called “A” sub-study and the so-called “B” sub-study to determine the factors associated with severe cases. Results: The factors associated with fatal cases in children between 1 to 59 months with CAP treated at the INSN were: Being between 1 to 5 months old (ORa = 3.61, CI: 1.1-11.76), acute malnutrition (ORa = 3.74, CI: 1.1-12.63), have multilobar consolidated (ORa = 3.1, CI: 1.006-9.5) and have consolidated in patch (ORa = 0.17, CI: 0.057-0.5). The factors associated with severe cases were: Being between 1 and 5 months old (ORa = 0.28, CI: 0.18-0.55), being preterm (ORa = 0.36, CI: 0.17-0.77), having diarrhea (ORa = 0.36, CI : 0.15-0.87), that the caregiver has a secondary education grade (ORa = 2.43, IC: 1.36-4.35), refuse to eat (ORa = 3.84, IC: 1.14-12.84) and have asthma (ORa = 10.66, IC: 1.11-102.3). Conclusions: The factors associated with mortality identified are: age between 1 to 5 months, having acute malnutrition, having consolidated multilobar. Risk factors for severity are: secondary caregiver education level, refusal to eat, and asthma. / Tesis