Récemment, les microbiotes pulmonaires bactériens d’un nombre très limité de patients atteints de mucoviscidose et de pneumopathies acquises sous ventilation mécanique (PAVM) ont été étudiés en utilisant l'amplification du gène 16S rDNA bactérien suivie par la construction de librairies de clones et différentes approches de séquençage. Ces études ont montré que la population microbienne de patients atteints de maladies respiratoires était plus diversifiée que prévue. Dans l'étude actuelle, nous utilisons une approche comparable pour identifier exhaustivement les agents pathogènes (bactéries, virus, et champignons) composant le microbiote pulmonaire associé aux pneumopathies développées en unités de réanimation. L'étude a inclus des patients admis en réanimation et présentant des formes de pneumopathies acquises sous ventilation mécanique (n = 106), de pneumopathies communautaires (n = 32), de pneumopathies nosocomiales sans ventilation mécanique (n = 22) et de pneumopathies d’aspiration (n = 25). Une cohorte de 25 patients admis en réanimation et ne présentant pas de symptômes de pneumopathie a été étudiée comme contrôle. Cette première partie du travail amènera ainsi à réaliser un catalogue exhaustif des agents de pneumopathies nosocomiales ; à connaître la prévalence des agents identifiés et d’identifier les co-infections fréquemment observées, et surtout à vérifier si ces agents peuvent être identifiés ou pas dans les prélèvements respiratoires profonds de patients non symptomatiques. Pour réaliser cette partie du travail, des séries de prélèvements, incluant des prélèvements de lavage broncho-alvéolaire (LBA), des prélèvements de sang et d'urine ont été étudiés. Ces prélèvements ont été testés par des moyens d’identification moléculaire moderne basés sur l’amplification de gènes conservés (gènes16S rDNA des bactéries et gène 18S rDNA des champignons) suivie par clonage et séquençage à grande échelle. D’autres pathogènes atypiques sont ciblés par des tests de PCR avec utilisation d’amorces spécifiques. Nous avons également inclus la culture, la co-culture d’amibes, la détection sérologique d'anticorps dirigés contre des agents sélectionnés et des tests d'antigène urinaire, afin de comparer ces tests de routine aux approches moléculaires. Comme résultats, les tests moléculaires nous ont permis d’identifier un vaste répertoire de 160 espèces bactériennes dont 73 n'ont jamais été précédemment rapportées à l’étiologie des pneumopathies. En outre, nous avons trouvé 37 phylotypes bactériens potentiellement nouveaux. Nous avons également identifié 24 espèces de champignons dont 6 n'ont pas été précédemment rapportées à l’étiologie des pneumopathies, 7 virus et étonnamment 6 espèces de plantes. De plus, certains agents pathogènes considérés comme typiques aux pneumopathies nosocomiales tels que Pseudomonas aeruginosa et des Streptococci ont été détectés chez les contrôles comme chez les patients. Cet étonnant résultat souligne l'existence d'un noyau de microbiote pulmonaire.Dans un deuxième travail, faisant suite aux travaux effectués dans notre laboratoire et qui ont pu mettre en évidence que 19% des pneumopathies nosocomiales étaient déterminées par des microorganismes associés aux amibes (MAAs) de l’eau préalablement ignorés ou négligés, nous avons utilisé un test d'immunofluorescence multiplexe pour tester la prévalence des anticorps contre les MAAs dans le sang de patients admis en réanimation et atteints de pneumopathies et la comparer à la prévalence au moment de l'admission. Comme résultat, nous démontrons que certains MAAs peuvent être plus fréquemment détectés après des épisodes de pneumopathies nosocomiales que lors de l’admission. En outre, la réponse immunitaire aux MAAs semble augmenter lorsque le séjour en réanimation est prolongé. Enfin, nous avons mis au point une stratégie de metagénomique pour tester les prélévements pour lesquels aucune étiologie n’a été retrouvée. [...] / Recently, bacterial microbiota from a limited number of patients with cystic fibrosis and ventilator-associated pneumonia (VAP) was studied using 16S rDNA gene amplification followed by clone libraries construction and sequencing. These studies have showed that the microbial population of patients with respiratory infections was more diverse than expected. In the current study, we use a similar approach to identify exhaustively the pathogens (bacteria, viruses, and fungi) comprising the microbiota associated with episodes of pneumonia developed in the intensive care units (ICU). Our study included patients admitted to ICUswith with episodes of ventilator-associated pneumonia (n = 106), community-acquired pneumonia (n = 32), nosocomial pneumonia without mechanical ventilation (n = 22) and aspiration pneumonia (n = 25). A cohort of 25 patients admitted to ICUs without symptoms of pneumonia were studied as controls. This first part of the work enables to prepare an exhaustive repertoire of nosocomial pneumonia pathogenes; to know the prevalence of the pathogens identified and to identify co-infections frequently observed, and especially to ascertain whether these agents can be identified or not in the respiratory samples of patients without symptoms of pneumonia. To perform this part of work, series of samples, including bronchoalveolar lavage (BAL) samples, blood samples and urine samples were collected. These samples were tested by means of modern molecular tools based on the amplification of conserved genes (bacterial 16S rDNA and fungal 18S rDNA genes), followed by highthroutput cloning and sequencing. The atypical pathogens are targeted by PCR tests using specific primers and probes. We also included culture, amoeba co-culture, serological detection of antibodies against selected agents and urinary antigen testing, to compare these routine tests to molecular approaches. Based on molecular testing, we identified a wide repertoire of 160 bacterial species of which 73 were never previously reported in pneumonia samples. Moreover, we found 37 putative new bacterial phylotypes. We also identified 24 fungal species of which 6 have not been previously reported in pneumonia, 7 viruses and surprisingly 6 plant species. Some pathogens considered being typical for ICU pneumonia such as Pseudomonas aeruginosa and Streptococcus species may be detected as commonly in controls as in pneumonia patients which strikingly highlight the existence of a core of pulmonary microbiota.In a second work, following previous works performed in our laboratory which were able to show that 19% of nosocomial pneumonia were determined by micro-organisms associated to amoebae (AAMs) previously ignored or neglected, we used a recent test based on multiplex serology to test for the prevalence of antibodies against the AAMs in the blood of patients admitted to ICU and developed episodes of pneumonia and compare it to the prevalence at the time of admission (controls). As a result, we demonstrate that some AAMs may be more frequently detected after episodes of nosocomial pneumonia than at the admission. In addition, the immune response to AAMS appears to increase when the ICU stay is prolonged.Finally, in order to explore samples for which no microbial aetiology was found, we have developed a subtractive hybridization metagenomic strategy and tested it on different clinical samples. The sensitivity of this strategy was also evaluated. We have demonstrated that our method, based on the detection of DNA and RNA of microorganisms in a single test, allows sensitive detection of different types of microorganisms.

Call number: LD2668 .T4 1963 G77 / Master of Science

published_or_final_version / Community Medicine / Master / Master of Public Health

Background: Healthcare-associated pneumonia (HCAP) guidelines were first proposed in 2005 but have not yet been validated. The objective of this study was to compare 30-day mortality and length of stay (LOS) in HCAP patients treated with either guideline-concordant HCAP (GC-HCAP) therapy or guideline-concordant community-acquired pneumonia (GC-CAP) therapy. Methods: We performed a retrospective cohort study of >150 hospitals in the Veterans Health Administration. Patients were included if they had ≥1 HCAP risk factor and received antibiotic therapy within 48 hours of admission. Patients were excluded if they received ICU care, had cardiovascular or respiratory organ failure, or received invasive mechanical ventilation and/or vasopressors. We determined independent risk factors for 30-day mortality with a multivariable logistic regression model including baseline characteristics, individual HCAP risk factors, comorbidities, and organ failure as dichotomous covariates. Propensity scores were calculated for the probability to receive GC-HCAP therapy and incorporated into a second logistic regression model. Results: A total of 15,071 patients met study criteria and received GC-HCAP therapy (8.0%), GC-CAP therapy (75.7%), or non-guideline-concordant therapy (16.3%). GC-HCAP patients were more likely to have neoplastic disease; whereas, GC-CAP patients had a higher prevalence of other comorbidities, tobacco use, and recent medication use. In multivariable regression, recent hospital admission (OR 2.47, 95% CI 2.10-2.91) and GC-HCAP therapy (2.13, 1.82-2.48) were the strongest predictors of 30-day mortality. Hematologic organ failure, non-invasive mechanical ventilation, neoplastic disease, renal organ failure, and cerebrovascular disease were also independent risk factors. Use of cardiovascular medications, inhaled corticosteroids, and tobacco were protective. GC-HCAP therapy continued to be an independent risk factor for 30-day mortality (OR 2.12, 95% CI 1.82-2.48) in the propensity score analysis. Conclusions: GC-HCAP therapy is not associated with improved survival in HCAP patients. / text

No description available.

No description available.

A key bacterial virulence factor is the ability to acquire the micronutrient iron, required by a vast majority of micro-organisms for survival and proliferation within their hosts. The work described here focuses on acquisition of iron in Pasteurella multocida serotype A:3, a Gram-negative opportunistic pathogen that causes pneumonic pasteurellosis in cattle, a severe respiratory infection of significant economic burden and welfare concern. P. multocida A:3 acquires iron primarily from the host iron-chelating molecule transferrin through the expression of specific outer membrane receptors. The correlation between up-regulation of these receptors and of other iron-regulated outer membrane proteins (IROMPs) and an increase in bacterial virulence has been noted elsewhere. To date, there has been no systems analysis of the metabolic processes of iron acquisition published for any bacterial species. The work described here used a systems approach involving elementary flux modes analysis to derive a computational model of iron acquisition and reveal a number of key findings on the mechanisms of iron acquisition and links between iron uptake, glucose metabolism and protein synthesis. This in silico model was subjected to experimental validation through a range of in vitro experiments designed to investigate the links between iron restriction and growth and metabolism of P. multocida. This novel approach was only possible after the development and optimisation of a number of assays to measure key model parameters.

Magister Public Health - MPH / Background: Malnutrition is a complex condition profoundly impacting child mortality and morbidity, especially in sub-Saharan Africa. Severe acute malnutrition is of growing concern locally where unacceptable mortality rates persist, despite reasonable standards of clinical care. Aim: To determine factors associated with morbidity and mortality in children under-five years admitted with severe acute malnutrition to a regional paediatric hospital in KwaZulu-Natal. Methodology: This was a quantitative study. A retrospective observational study design was used. Medical records of all children with severe acute malnutrition, under the age of five years, admitted between April 2015 and December 2016 to the regional paediatric hospital in KwaZulu-Natal were included. Data was obtained from medical records and admission books. A trained research assistant was used to extract and record data with a piloted data extraction tool. Data was entered and cleaned using Microsoft Excel and analysed using SPSS (v 20) and STATA (v 14). Descriptive summary statistics were used to describe the characteristics of the study population and bivariate analysis using t-tests and Chi-square tests to determine significance. Kaplan Meier and Multivariate Cox regression was used to assess the association of variables with morbidity and mortality. Results: Of the 276 eligible case records included in the study, 54% were male and 90% of all cases were younger than 2 years. Even though associations did not reach significance, teenage pregnancy and unemployment was high amongst the caregivers of the study population. Most of the malnourished children admitted (74%) presented with multiple comorbidities. Diarrhoea (43%), HIV- infection (30%) and respiratory tract infections (30%) were the top three comorbidities found, followed by tuberculosis (27%). The overall mortality rate was 8.7%. Survival probability was significantly reduced in children with pneumonia and those who presented with hypoglycaemia, dehydration, dermatosis, severe pallor, altered consciousness or shock on admission (p < 0.05). There was a significantly increased risk of death in males (HR = 0.174, 95%CI = 0.05 - 0.665), and in those who presented with dehydration (HR = 4.1, 95%CI = 1.25 - 13.59), evidence of lethargy or coma (HR = 4.2, 95%CI = 1.04 - 17.12) or multiple clinical signs (HR = 4.4, 95% CI =2.56 - 7.59) on admission (p < 0.05). The comorbidities HIV-infection (HR = 9.9, 95%CI = 1.39 - 70.68) and pneumonia (HR = 3.4, 95%CI = 1.56 - 7.43) showed a significantly increased mortality risk (p < 0.05). Conclusion: This study supports the body of evidence that despite reasonable standards of hospital care, it is difficult to obtain the target for severe acute malnutrition mortality (< 5%), likely due to the presence of contextually specific factors. Local interventions at hospital, primary health care and community level is needed, as well as further research to facilitate comprehensive policy-making.

M.Sc.(Med.), Faculty of Health Sciences, University of the Witwatersrand, 2009 / Community-acquired pneumonia (CAP) is a major cause of morbidity and mortality worldwide. Knowledge of the predominant agents associated with CAP locally is essential, as it represents the basis for empiric antibiotic treatment. The objective of this study was to establish polymerase chain reaction (PCR)-based methods that could be used to identify CAP pathogens. Real-time PCR assays were developed to detect 10 viral and 5 non-viral pathogens as well as 2 internal controls using SYBR Green I and TaqMan probes, in singleplex and multiplex reactions. Six multiplex assays, with sensitivities of 1-10 copies/μl, were successfully developed to simultaneously detect 12 organisms. These reactions were used to test a limited number of patient and simulated samples. Data from the real-time PCR methods compared favourably to those from commercially available conventional PCR kits. These detection methods could be used to complement each other in prevalence studies and in selected diagnostic applications.

Introdução: Atualmente a incidência anual de pneumonia adquirida na comunidade nos países em desenvolvimento é de 150,7 milhões de casos entre crianças menores de 5 anos de idade , dos quais 11 a 20 milhões (7-13%) necessitam de internação hospitalar devido à gravidade. O tratamento geralmente é empírico mas o Streptococcus pneumoniae é o principal agente etiológico bacteriano.É necessário manter monitoramento dos sorotipos e padrão de resistência para melhor orientação terapêutica. Metodologia: Estudo de coorte retrospectivo com inclusão de 107 crianças com diagnóstico clínico e radiológico de pneumonia e com isolamento de Streptococcus pneumoniae em sangue e ou líquido pleural no período de janeiro de 2003 a outubro de 2008. Realizado determinação de concentração inibitória mínima (MIC) para penicilina e antibiograma para outros antimicrobianos. A sensibilidade para penicilina utilizada foi conforme Clinical and Laboratory Standards Institute (CLSI ) de 2008. Realizado sorotipagem de 96 cepas de pneumococos (89,7%) e analisados os dados da população em estudo e da evolução clínica. Resultados:Cerca de 47,5% das internações na enfermaria foram por pneumonia ou broncopneumonia e a média de positividade em cultura para pneumococo (sangue e ou líquido pleural) foi de 2,5%. Houve uma sazonalidade bem definida da pneumonia pneumocócica. Cerca de 70% ocorreram nos meses de junho a outubro. A mediana de idade foi de 23 meses (82,2%<5anos); predomínio do sexo masculino (58,9%);utilização de antibioticoterapia nos dois meses prévios à internação de 23,4%; freqüência em creche no menores de 2 anos de 36,4%; apenas um caso com vacinação heptavalente completa; doença associada em 44,9% sendo a mais freqüente a sibilância( 77,1%); tempo de febre e de sintomas respiratórios antes da admissão foi de 4 dias;necessidade de oxigenoterapia não invasiva em 70,1% com tempo médio de utilização de 4 dias;necessidade de ventilação mecânica em 19,6%, mediana do tempo de internação de 9 dias.Em 62% houve complicações sendo as mais freqüentes: empiema (53%) e efusão pleural não complicada (42%). As crianças com empiema tiveram mais pneumonia necrotizante, abscesso pulmonar, sepse, pneumotórax, necessidade de decorticação e ainda maior mortalidade (todas com p<0,05). As crianças com complicações tiveram mais dias de sintomas respiratórios antes da admissão (3x5dias), mais tempo de febre após o início de antibiótico (1x4,5dias), necessitaram de oxigenoterapia não invasiva(58,5x77,3%) e ventilação mecânica (7,3x27,3%) por tempo maior e permaneceram por mais tempo internados (5x12 dias). Das 107 cepas de pneumococo, 100 (93,5%) foram sensíveis à penicilina e 7 (6,5%) de sensibilidade intermediária. Todas as cepas testadas foram sensíveis para rifampicina e vancomicina e ainda mantiveram boa sensibilidade para clindamicina, cloranfenicol, ceftriaxone, eritromicina e levofloxacina. Cinco cepas foram multiresistentes. Notou-se que a média geométrica das concentrações inibitórias mínimas (GMC) para penicilina foram maiores nas crianças com complicações. Os sorotipos mais freqüentes foram: 14(36,5%), 1(16,7%) , 5(14,6%) e 6B(6,3%). O sorotipo 14 apresentou a maior GMC para penicilina e houve um aumento progressivo no decorrer dos anos de estudo. A cobertura dos sorotipos pela vacina heptavalente seria de 53,1% e esta cobertura menor se deve principalmente ao sorotipo 1 e 5, que corresponde a 31,3% dos casos. A cobertura dos sorotipos associados à resistência seria de 94,2%. A cobertura pela vacina 10-valente seria de 86,5% e com a 13-valente seria de 96,9%. Três casos que evoluíram para óbito (2,8%) tinha mediana de idade de 18 meses, todos do sexo masculino, todos com concentração inibitória mínima para penicilina menor ou igual 1g/mL, todos evoluíram com empiema e sepse. Dois foram do sorotipo 5 e um do sorotipo 14. Conclusões: Aproximadamente 2,5% das crianças internadas com diagnóstico de pneumonia foram diagnosticadas como pneumonia pneumocócica.Verificamos uma sazonalidade bem definida.Houve complicações em 62% dos casos. As mais freqüentes foram : empiema e a efusão pleural não complicada. Evidenciou-se uma GMC para penicilina maior nas crianças com complicações comparadas às crianças com ausência de complicações. Os sorotipos mais freqüentes foram 14,1 ,5 e 6B sendo que os sorotipos 1 e 5 totalizam 31,3%. A cobertura pela vacina heptavalente dos sorotipos isolados seria de 53,1%. A sensibilidade para penicilina dos pneumococos isolados de pneumonia foi de 93,5%. Assim, a opção terapêutica continua sendo a penicilina. / Introduction: Currently, the annual incidence of the acquired pneumonia in the developing country communities are around 150.7 million cases, among childrens under 5 years of age, and 11 to 20 million (7-13%) of those require hospitalization due to their gravity. In general, the treatments used to be empirical, however, it is important to be noted that Streptococcus pneumoniae is far the major bacterial etiologic agent. It is necessary to keep monitoring the serotypes and the pattern of resistance in order to improve the therapy guidance. Methodology: Retrospective cohort study with inclusion of the 107 childrens with clinical and radiological diagnosis of the pneumonia, and the isolation of Streptococcus pneumoniae in the blood and/or pleural fluid during the period of January 2003 to October 2008. It was performed determination of the minimum inhibitory concentration (MIC) related to the penicillin and other antibiotics. The sensitivity analysis to the penicillin was based on Clinical and Laboratory Standards Institute (CLSI), 2008, recommendations. They were performed serotyping in 96 pneumococcal strains (89.7%) and they were analyzed datas referred to the considered population and their clinical course. Results: About 47.5% of admissions in the ward were caused by pneumonia or bronchopneumonia, and the average positive occurrences in the pneumococcal (blood and / or pleural) culture were 2.5%. It was noted a clear seasonality phenomena of the pneumococcal pneumonia. About 70% of the cases occurred during months of June to October. The median age was 23 months (82.2%<5 years); with predominance of males (58.9%); in the 23,4% of the cases the antibiotic therapy was used during two months prior to the admission; the daycare frequency of the childs less than 2 years were 36.4%; only one case with complete vaccination heptavalent; associated disease was detected in the 44.9% of the cases and the most frequent was wheezing (77.1%); time of fever and respiratory symptoms before admission were 4 days; the need for noninvasive oxygen therapy occurred in 70.1% being 4 days of the average time of the use; the need for mechanical ventilation occurred in 19.6%; the median period of stay were 9 days. In 62% of the cases there were the most frequent complications: empyema (53%) and non-complicated pleural effusion (42%). The childrens with empyema had more necrotizing pneumonia, lung abscess, sepsis, pneumothorax, need for decortication, and even higher mortality (all with p<0.05). The childrens with complications had more days of respiratory symptoms before admission (3x5days), more time of the fever after initiation with antibiotic (1x4, 5days), they need noninvasive oxygen therapy (58,5 x77, 3%) and mechanical ventilation (7 , 3x27, 3%) for more time and remained hospitalized during longer period(5x12 days). Among 107 pneumococcal strains, 100 (93.5%) were susceptible to penicillin and 7 (6.5%) presented intermediate sensitivity. All strains tested were sensitive to rifampicin and vancomycin, and they maintained good sensitivity to clindamycin, chloramphenicol, ceftriaxone, erythromycin and levofloxacin. Five strains were multi-resistant. It was noted that the geometric mean of minimum inhibitory concentrations (GMC) to penicillin were higher in children with complications. The most frequent serotypes were: 14 (36.5%), 1 (16.7%), 5 (14.6%) and 6B (6.3%). The serotype 14 presented the highest GMC for penicillin and it was verified a progressive increase during the years of the study. The coverage of serotypes by the heptavalent vaccine would be cover 53.1% and this less coverage is represented by serotype 1 and 5, which corresponds to 31.3% of the cases. The coverage of serotypes associated with resistance would be 94.2%. The coverage of the 10-valent vaccine would be 86.5% and for 13-valent would be 96.9%. Three cases that carried to died (2.8%) had median age of 18 months, all they male, all they with minimum inhibitory concentration for penicillin <= 1g/mL, all they progressed to empyema and sepsis. Two of them were serotype 5 and one of them was serotype 14. Conclusions: Approximately 2.5% of children were admitted with diagnosis of pneumonia were diagnosed as pneumococcal pneumonia. It was verified a clear seasonality phenomena. They were observed complications in 62% of the cases. The most frequent were: empyema and non-complicated pleural effusion cases. It was confirmed a higher GMC for penicillin in children with complications compared to the children without complications. The most frequent serotypes were 14, 1, 5 and 6B and the serotypes 1 and 5 accounted 31.3%. The coverage of heptavalent vaccine for the isolated serotypes would be 53.1%. The sensitivity to the penicillin of the isolated pneumococcal was 93.5%. Therefore, the therapy option remains being the penicillin.