Orientador: Marcelo de Carvalho Ramos / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T07:44:31Z (GMT). No. of bitstreams: 1 Panunto_AlessandraCosta_D.pdf: 4929023 bytes, checksum: e09c1fb4f0b9ff64c05e8133763291d7 (MD5) Previous issue date: 2007 / Resumo: O M. Avium é um microrganismo oportunista e sua infecção é feeqüentemente encontrada em pacientes com aids no Brasil, apesar do largo uso da quimioterapia antiretroviral altamente efetiva. Este estudo documenta a relevância desse problema. Dentro de uni número significante de pacientes (n=39) infectados com o M. avium, os isolados puderam ser recuperados de uma variedade de espécimes clínicos. Todos os isolados (n=45) foram tipados pela técnica de RFLP usando a seqüência 1S1245. A maioria dos pacientes (n=35) eram infectados pelo HIV. Somente duas cepas não puderam ser tipadas por causa da ausência da seqüência detectável pela 1S1245. Nas 43 cepas restantes os "blots" apresentaram de 6 a 23 bandas. Uma média de 17 seqüências foram observadas para cada cepa. Para alguns pacientes, mais de um isolado pode ser recuperado. Em dois pacientes deste grupo com doença disseminada, o M. avium pode ser recuperado mais de uma vez. De cada paciente, pelo menos duas amostras com diferentes genótipos foram recuperadas de locais estéreis, indicando que eles tinham infecções policlonais. Esses achados têm sido relatados por outros autores. Em um estudo recente, SAAD et aI., 2000, demonstrou que isolados de infecções policlonais e diferentes "fmgerprints" podem apresentar diferentes suscetibilidade antimicrobiano. Quatro "clusters" de pacientes puderam ser identificados. O maior "cluster" foi composto de oito pacientes. Estes resultados indicam que um mecanismo de transmissão recente ocorreu. A fonte de contaminação desses microrganismos não pode ser determinada. Assim, a transmissão pessoa a pessoa não apresentou uma importância significativa na transmissão desse microrganismo. Nós supomos que esses pacientes adquiriram o microrganismo de fontes hospitalares como água, alimento ou mesmo do ambiente / Abstract: not informed. / Doutorado / Ciencias Basicas / Doutor em Clínica Médica

A Pirazinamida (Z), droga de primeira linha usada no tratamento da tuberculose, necessita ser hidrolisada pela enzima bacteriana pirazinamidase (PZase) para que o seu metabólito ativo, o ácido pirazinóico (POA), possa agir. O principal mecanismo molecular de resistência a esta droga envolve mutações no gene pncA, que codifica a PZase. Com base nestas informações e tendo em vista a ausência de estudos acerca de resistência à Z em isolados clínicos de M. tuberculosis em nosso país, o presente trabalho propôs caracterizar as mutações envolvendo o gene pncA, bem como relacioná-las com os resultados do teste de atividade da enzima PZase e da concentração inibitória mínima (CIM) de Z. A caracterização molecular dos isolados foi realizada por \"Spoligotyping\", sendo que, todos os isolados testados foram confirmados como pertencentes à espécie M. tuberculosis. A CIM foi realizada por três metodologias: técnica em microplaca utilizando o Alamar Azul como revelador (MABA), método de microdiluição em caldo (BMM), e método das proporções em Lowenstein-Jensen. Os resultados obtidos dão conta de uma boa associação entre as metodologias, e a determinação da CIM pelo método MABA mostrou-se uma nova e segura opção a ser utilizada para Z. A maioria dos isolados clínicos de M. tuberculosis resistentes à Z (88%), apresentaram também atividade de PZase negativa, bem como mutações no gene pncA. Algumas exceções foram encontradas, já que 12% dos isolados clínicos resistentes não apresentaram mutações no gene pncA e tiveram atividade da PZase positiva, sugerindo a existência de outro mecanismo envolvido com resistência à Z. Das 22 mutações encontradas no gene pncA, 9 estão sendo descritas apenas neste estudo. Registrou-se também a presença de 5 isolados clínicos apresentando fenótipo de monorresistência à Z. / Pyrazinamide (Z), a first-line antituberculous drug, is a prodrug that must be activated by bacterial pyrazinamidase (PZase) to the active form pyrazinoic acid, which kills M. tuberculosis. Many studies have shown that mutation in the gene encoding PZase (pncA) is the major mechanism of Z-resistance in M. tuberculosis. Based on this information and taking into consideration the absence of studies concerning Z-resistance in Brazilian M. tuberculosis strains, this study was aimed at characterizing pncA mutations and investigating its correlation with Z-resistance and PZase activity. The molecular characterization carried out by Spoligotyping revealed that all tested strains belong to M. tuberculosis species. The minimal inhibitory concentration (MIC) of Z was determined by three methods: microplate Alamar Blue assay (MABA), broth microdilution method (BMM) and method of proportions on Lowenstein-Jensen medium. The results showed a good association between the 3 methods, and MABA for MIC determination signalized a new and safe option to be used for Z. Most of Z-resistant strains (88%) presented pncA mutations as well as loss of PZase activity. Some exceptions were found since 12% of Z-resistant strains presented neither pncA mutations nor loss of PZase activity, what suggests the existence of another Z-resistance mechanism. Nine of 22 mutations found in pncA gene were described only in this study. During the course of this investigation were identified 5 Z-monoresistant M. tuberculosis strains.

The World Health Organization (WHO) estimated that eight million new cases of tuberculosis (TB) occur every year and that one-third of the world’s population is infected with Mycobacterium tuberculosis (M. tuberculosis). With the increase in HIV/AIDS in the 1980’s, an increase in transmission of TB led to an increase in TB incidence. A study showed that South African adults (ages 15 to 49) will suffer 278 154 deaths between 2008 and 2017 if current control measures are continued. A M. tuberculosis strain that is resistant to isoniazid (INH) and rifampicin (RIF) used in the treatment of TB is known as a multi-drug resistant (MDR-TB) strain. In extensively drugresistant tuberculosis (XDR-TB) the M. tuberculosis strains are not only resistant to INH, RIF and any one of the fluoroquinolones but to at least one of the three injectable second-line drugs such as amikacin or kanamycin. Unfortunately, many people with XDR-TB will die because it is virtually impossible to formulate an effective treatment before the resistance pattern of the M. tuberculosis strain has been identified. Bacteriological culture is considered the diagnostic gold standard and can identify mycobacteria in over 80% of TB cases, with a specificity of over 98%. However, culturing the mycobacteria takes 4 to 6 weeks and makes diagnosis and treatment a prolonged process. In this study 60 patients suspected of TB disease, from the Anti-retroviral (ARV) clinic at the Tshwane District Hospital (TDH) were collected from October 2008 to April 2009. This study evaluated the use of the QuantiFERON-TB GOLD ELISA assay in a high burden setting. Tshwane District Hospital, South Africa. The sensitivity and specificity of the QFT assay in the clinic were 30% (9/30) and 63% (19/30) respectively when compared to the gold standard culture results. Analysis suggested that the sensitivity of the QuantiFERON assay is determined by a limiting patient CD4 value of between 150 and 200. Real-time PCR assays were used for rapid identification of Mycobacterium spp and to determine the presence of isoniazid and rifampicin resistant genes of M. tuberculosis strains. The real-time PCR assay identified 28% (17/60) M. tuberculosis, 2% (1/60) M. kansasii and 70% (42/60) of the isolates Mycobacterium spp negative. No M. avium were detected. The 17 M. tuberculosis positive specimens were further analysed for the presence of INH and RIF resistance genes. All 17 specimens had either no mutation or one or more mutations at the specific gene targets (rpo1, rpo2, katG and inhA). This study showed several possibilities for the use of both an immunological assay as well as molecular methods for the diagnosis of TB. This study suggested that in terms of routine diagnosis of TB in high HIV prevalence settings the QFT test should be used with caution. Realtime PCR for both detection and identification showed useful results and can be used together with culture results to improve turnaround times for TB diagnosis. Copyright / Dissertation (MSc)--University of Pretoria, 2010. / Medical Microbiology / unrestricted

Tuberculosis (TB) is the leading cause of death among HIV infected people. Mycobacterium tuberculosis (M. tuberculosis), the causative agent of TB, features a distinctive lipid-rich cell wall with mycolic acids (MA) the major component in the outer layer. Mycolic acids are á-alkyl â-hydroxy long chain fatty acids, which exist in a number of chemical subclasses depending on the presence of functional oxygenated and non-oxygenated groups in the meromycolate chain. In numerous studies the different MA subclasses have been shown to play different roles in antibody recognition, virulence and the ability to attract cholesterol. It was previously suggested that the oxygenated MA might be important for these properties. Except for the mycolic acid motif, little is known about the stereochemistry of the other chiral centres. The importance of the different functional groups, their position and stereochemistry, for immunological properties, are not yet clarified. This study set out to resolve the structureactivity relationships of mycolic acids from M. tuberculosis in terms of their antigenicity and the ability to attract cholesterol. To determine fine specificity of interaction of MA with antibodies, the subclasses of MA from M. tuberculosis were separated and the antigenicity of two was determined. TB+ and TB- patient sera recognised natural MA, alpha-MA and methoxy-MA. It was confirmed that the carboxylic acid group played a fundamental role in its recognition. Interestingly, cord factor (trehalose-6,6’-dimycolate) was recognised specifically by TB+ sera. This implies multiple epitopes in the MA structure, some of which are very specific for TB patients. A stereocontrolled diastereomer of cis-cyclopropane methoxy-MA was synthesized and along with other synthetic methoxy-, keto- and hydroxy-MAs, were tested for antibody recognition. One diastereomer, SS-SR-methoxy-MA, was recognised stronger by TB+ serum than the other, it also is the one that closest approximates the signal strength of antibody binding to natural MA by TB+ patient sera. While the others are not specifically recognised, this SS-SR-methoxy-MA may well represent one of the antigenically active components that occurs in natural MA and that elicits specific antibodies in TB patients. This thesis reports a stereocontrolled chemical synthesis of biologically active mycolic acids and shows that a single component of the mycolic acid mixture can be sufficient to elicit an immunological response. / Thesis (PHD)--University of Pretoria, 2008. / Biochemistry / unrestricted

Determina la prevalencia de tuberculosis pulmonar (TBP) en pacientes adultos con ≥ 2 horas de admisión al DE. Evalúa la definición de tamizaje de casos “capacidad de entregar una muestra de esputo sin importar la duración de tos”, y el rendimiento diagnóstico (RD) del “cultivo a todas las muestras”. Determina criterios para la generación de algoritmos diagnósticos y de aislamiento en este escenario. Es un estudio transversal de 14 meses. Se obtuvo muestras de esputo para baciloscopía y cultivo. Realiza análisis bivariado y multivariados (AMV) a fin de determinar factores de riesgo para TBP y TB multidrogoresistente (TB MDR). Se elaboraron Modelos de Score Clínicos (MSC) con los criterios que resultaron significativos en los AMV. Se generaron algoritmos diagnósticos utilizando el criterio de sospecha clínica, los resultados de los MSC, baciloscopía, Xpert® MTB/RIF y costos de aislamiento. Se enroló 1001 pacientes de los cuales 21.3% tuvieron TBP. De estos, 21.4% tuvieron TB MDR, 19.15% con coinfección VIH/TB MDR y 27.27% tuvieron VIH y no TB-MDR. El criterio de inclusión propuesto permitió un incremento del rendimiento diagnóstico de 63.4% y 47.5%, en relación a la duración de tos y el cultivo respectivamente, en comparación con el estándar OMS. Los parámetros para la elaboración de algoritmos obtenidos fueron: los MSC como pasos iniciales generan mayor “costo epidemiológico”, el uso de la baciloscopía como primer paso, disminuye el “costo epidemiológico”, la prueba Xpert® MTB/RIF, disminuye las necesidades y costos de aislamiento, y el aislamiento genera más “costo financiero” que las pruebas de diagnóstico. Concluye que existe una elevada carga y riesgo de transmisión de TBP en el DE evaluado, por lo que el tamizaje rutinario y aislamiento deben incorporarse en los algoritmos de diagnóstico de TBP. / Tesis

Pang, Tak Ting Phoebe. / "September 2010." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 153-161). / Abstracts in English and Chinese. / Acknowledgement --- p.I / Abstract --- p.II / 摘要 --- p.IV / List of Figures --- p.V / List of Tables --- p.VII / Abbreviations --- p.VIII / Chapter CHAPTER ONE --- INTRODUCTION --- p.1 / Chapter 1.1 --- Historical perspective of tuberculosis --- p.1 / Chapter 1.1.1 --- Sanatorium care --- p.2 / Chapter 1.1.2 --- Vaccination --- p.2 / Chapter 1.1.3 --- Drug treatment --- p.3 / Chapter 1.1.4 --- Transmission dynamics of tuberculosis --- p.3 / Chapter 1.1.5 --- Resurgence of tuberculosis --- p.4 / Chapter 1.2 --- Current global and local tuberculosis epidemiology --- p.6 / Chapter 1.2.1 --- "Tuberculosis and HIV/AIDS, drug resistance in the world" --- p.6 / Chapter 1.2.2 --- Global epidemiology of tuberculosis --- p.9 / Chapter 1.2.3 --- Local epidemiology of tuberculosis --- p.9 / Chapter 1.2.4 --- "Tuberculosis, HIV/AIDS and drug resistance in Hong Kong" --- p.14 / Chapter 1.2.5 --- Approaches in studying tuberculosis epidemiology --- p.15 / Chapter 1.3 --- Determinants of tuberculosis epidemiology --- p.17 / Chapter 1.3.1 --- TB determinants in the triad of epidemiology --- p.17 / Chapter 1.3.2 --- Rise of spatial epidemiology --- p.18 / Chapter 1.4 --- Recent developments of spatial epidemiology --- p.21 / Chapter 1.4.1 --- Spatial epidemiology and infectious disease --- p.21 / Chapter 1.4.2 --- Disease mapping --- p.22 / Chapter 1.4.3 --- Geographic information system --- p.22 / Chapter 1.4.4 --- Statistics in spatial epidemiology --- p.23 / Chapter CHAPTER TWO --- LITERATURE REVIEW --- p.24 / Chapter 2.1 --- Objective of literature review --- p.24 / Chapter 2.2 --- Literature search --- p.25 / Chapter 2.2.1 --- Strategy for literature search --- p.25 / Chapter 2.2.2 --- Results for literature search --- p.25 / Chapter 2.3 --- Spatial perspective in tuberculosis epidemiology --- p.31 / Chapter 2.3.1 --- Mapping the spatial pattern --- p.32 / Chapter 2.3.2 --- Understanding the spatial pattern --- p.32 / Chapter 2.3.3 --- Modelling the spatial pattern --- p.33 / Chapter 2.4 --- Neighbourhood determinants of tuberculosis --- p.34 / Chapter 2.4.1 --- TB and demographics --- p.35 / Chapter 2.4.2 --- TB and socioeconomic status --- p.36 / Chapter 2.4.3 --- TB and the environment --- p.38 / Chapter 2.4.4 --- TB and care factors --- p.40 / Chapter 2.5 --- Techniques applied in studying tuberculosis epidemiology --- p.41 / Chapter 2.5.1 --- Constructing spatial data --- p.41 / Chapter 2.5.2 --- Disease maps used --- p.45 / Chapter 2.5.3 --- "Integrated approach using spatial statistics, conventional statistics and molecular analysis" --- p.52 / Chapter 2.6 --- Research gap and thesis objectives --- p.55 / Chapter 2.6.1 --- Research gap --- p.55 / Chapter 2.6.2 --- Thesis objective --- p.56 / Chapter CHAPTER THREE --- METHODOLOGY --- p.57 / Chapter 3.1 --- Rationale and approach --- p.57 / Chapter 3.1.1 --- Logical flow of the study --- p.57 / Chapter 3.1.2 --- Methodological flow of the study --- p.60 / Chapter 3.2 --- Choosing spatial units --- p.63 / Chapter 3.3 --- Data collection --- p.69 / Chapter 3.3.1 --- Tuberculosis data --- p.70 / Chapter 3.3.2 --- Spatial data --- p.70 / Chapter 3.3.3 --- Neighbourhood data --- p.70 / Chapter 3.4 --- Data manipulation --- p.73 / Chapter 3.4.1 --- Tuberculosis data --- p.73 / Chapter 3.4.2 --- Spatial data --- p.74 / Chapter 3.4.3 --- Neighbourhood data --- p.74 / Chapter 3.5 --- Centrographic analysis --- p.76 / Chapter 3.5.1 --- Types of centrographic statistics --- p.76 / Chapter 3.6 --- Exploratory spatial data analysis --- p.78 / Chapter 3.6.1 --- Spatial proximity matrix --- p.78 / Chapter 3.6.2 --- Moran's Index --- p.79 / Chapter 3.6.3 --- Local Indicator of Spatial Association --- p.79 / Chapter 3.7 --- Explanatory analysis --- p.81 / Chapter 3.7.1 --- Selecting variables for modelling --- p.82 / Chapter 3.7.2 --- Ordinary linear regression --- p.82 / Chapter 3.7.3 --- Geographically weighted regression --- p.83 / Chapter CHAPTER FOUR --- RESULTS --- p.85 / Chapter 4.1 --- Overview --- p.85 / Chapter 4.1.1 --- Individual level --- p.85 / Chapter 4.1.2 --- Aggregated level --- p.89 / Chapter 4.2 --- Results for centrographic analysis --- p.97 / Chapter 4.3 --- Results for exploratory spatial data analysis --- p.101 / Chapter 4.3.1 --- Results for Moran's Index --- p.101 / Chapter 4.3.2 --- Results for Local Indicator of Spatial Association --- p.103 / Chapter 4.4 --- Results for explanatory analysis --- p.110 / Chapter 4.4.1 --- Correlation analysis and variables selection --- p.110 / Chapter 4.4.2 --- Results for ordinary linear regression --- p.114 / Chapter 4.4.3 --- Results for geographically weighted regression --- p.116 / Chapter CHAPTER FIVE --- DISCUSSION --- p.131 / Chapter 5.1 --- Preamble --- p.131 / Chapter 5.1.1 --- Methods overview --- p.132 / Chapter 5.1.2 --- Results overview --- p.132 / Chapter 5.1.3 --- Layout of this chapter --- p.134 / Chapter 5.2 --- Neighbourhood determinants in relation to TB --- p.135 / Chapter 5.2.1 --- Crowding and tuberculosis --- p.135 / Chapter 5.2.2 --- Poverty and tuberculosis --- p.137 / Chapter 5.2.3 --- Immigrants and tuberculosis --- p.138 / Chapter 5.2.4 --- Marital status and tuberculosis --- p.139 / Chapter 5.2.5 --- Implication of local parameter estimates of association --- p.140 / Chapter 5.3 --- Study design for spatial epidemiology --- p.142 / Chapter 5.3.1 --- Application of spatial dependence in spatial epidemiology --- p.142 / Chapter 5.3.2 --- Choosing spatial units --- p.144 / Chapter 5.4 --- Methodological concern in this study --- p.146 / Chapter 5.4.1 --- Concern over disease mapping --- p.146 / Chapter 5.4.2 --- Application of geographically weighted regression --- p.148 / Chapter 5.5 --- Limitation of the study --- p.150 / Chapter 5.6 --- Conclusion --- p.152 / REFERENCE --- p.153 / APPENDIX --- p.162 / Appendix 1 How to calculate TB SNR? --- p.162 / Appendix 2 How GWR works? --- p.164 / Appendix 3 What is AIC? --- p.165 / Appendix 4 How Monte Carlo test works? --- p.166 / Appendix 5 List of GWR output --- p.167

The study aimed to explore and describe the experiences of people treated for multidrug resistant tuberculosis (MDR-TB) in Omaheke region, Namibia in order to make relevant recommendations regarding their management. A descriptive qualitative design approach was used. Data was collected using in-depth individual interviews with six participants. The interview transcripts were analysed using thematic content analysis. Three themes emerged namely (1) Stressors related to MDR-TB diagnosis and treatment which involved nature of disease and compulsory hospitalisation (2) Impact of being treated for MDR-TB which related to emotional , social , spiritual and financial impact (3) Support structures for people treated for MDR-TB which included family members, health care professionals and friends. Systemic practical patient-centred, staff-centred and community-centred recommendations are suggested as well as recommendations for future research and an appraisal of the limitations of this study. / Health Studies / M.A. (Public Health)

Submitted in partial fulfilment of the requirements for the Degree of Masters in Technology: Clinical Technology, Durban University of Technology, 2013. / Introduction : Effusive constrictive pericarditis (ECP) is a clinical syndrome characterized by concurrent pericardial effusion and pericardial constriction where constrictive haemodynamics are persistent after the pericardial effusion is removed. Although first observed in the 1960s, it was not until the publication of a 13 patient-case series by Hancock in 1971, and the prospective cohort publication by Sagrista-Sauleda in 2004, that more information about the aetiology, incidence, and prognosis of effusive-constrictive pericarditis became known (Sagrista-Sauleda, Angel, Sanchez, Permanyer-Miralda, and Soler-Soler 2004). Hancock (1971) first recognized that some patients presenting with cardiac tamponade did not have resolution of their elevated right atrial pressure after removal of the pericardial fluid. In these patients, pericardiocentesis converted the haemodynamics from those typical of tamponade to those of constriction. Thus, the restriction of cardiac filling was not only due to the pericardial effusion but also resulted from pericardial constriction (predominantly the visceral pericardium). The hallmark of effusive-constrictive pericarditis is the persistence of elevated right atrial pressures after the intrapericardial pressure has been reduced to normal levels by the removal of the pericardial fluid. Aims and Objectives : This study was carried out to determine the prevalence of ECP in a cohort of patients with large effusions of Tuberculosis origin. The primary objective was to measure pre and post- pericardiocentesis intrapericardial and right atrial cardiac pressures in all patients undergoing pericardiocentesis in order to determine the relative proportion of effusive constrictive pericarditis in these patients. The secondary objective was to determine if any echocardiographic features can help predict the presence of ECP by studying the three parameters two-week post-pericardiocentesis. Methodology : Fifty consecutive patients with pericarditis presenting to Groote Schuur Hospital and surrounding hospitals referred for pericardiocentesis, who met the inclusion criteria were recruited to participate in the study. All patients had the right atrial and intrapericardial pressures simultaneously measured and recorded, before and after pericardiocentesis. The pressures were analyzed to determine the presence of ECP, which was defined as failure of the right atrial pressure to fall by 50% or to a new level of ≤12 mmHg after the intrapericardial pressure is lowered to below 2 mmHg. Participants also had an echocardiogram done two weeks post pericardiocentesis. Three echocardiographic features of constriction were studied, to determine if they can predict the presence of ECP. The parameters studied were 1) Thickened pericardium, 2) Dilated inferior vena cava (IVC) and 3) Septal bounce. Results : This study showed a 34% (17 0f 50) prevalence of ECP in patients with TB pericarditis. It also showed a statistically difference in the right atrial and intrapericardial pressures pre and post pericardiocentesis, between patients with ECP and those without. The echocardiographic parameters studied showed no difference between ECP and non ECP, and also did not predict the presence of ECP. Discussion : In the cohort of patients (n=50), the prevalence of ECP was found to be 34%. This is much higher than that observed in the Sagrista-Sauleda et al., (2004) study. They found a prevalence of 1.3% amongst patients with pericardial disease of any type and 6.95% amongst patients with clinical tamponade. The authors did state that they expected the true prevalence to be higher than estimated as not all patients underwent catheterization. Pre-pericardiocentesis pressures, both right atrial and intrapericardial, were found to be higher in patients with ECP than in those without. This is in keeping with published results, such as the study of Hancock (1971) The echocardiographic parameters studied were two weeks post pericardiocentesis, because the diagnostic accuracy of echocardiogram has been shown to be very poor at the time of tamponade. The presence of these parameters (thickened pericardium, dilated IVC and septal bounce), did not predict the presence of ECP. This could be due to the fact that less than 50% of participants had an echocardiogram two weeks post pericardiocentesis. Conclusions : The results of this study show that ECP is actually more common than thought in a population with TB pericarditis. This syndrome may be missed in most patients due to the fact that not all centres measure right atrial and intrapericardial pressures at the time of pericardiocentesis. Echocardiography is not able to predict the presence of ECP. Other non-invasive imaging techniques such is computerized tomography (CT) and cardiac magnetic resonance imaging (CMRI) have shown good results in diagnoses of ECP. The importance of early diagnosis of ECP lies in recognition that removal of pericardial fluid alone may not be enough; patients may need to have surgery. Given the high prevalence shown by the study, ideally all patients with pericardial effusion should have haemodynamic monitoring at the time of pericardiocentesis.

Introduction: Despite management advances worldwide, tuberculosis still remains a serious uncontrolled disease. The absence of either a ‘gold’ standard diagnostic test, or a conventional rapid ‘reference’ laboratory test for asymptomatic Mycobacterium tuberculosis (MTB) carriers complicates disease control. Through mandatory screening of high-risk groups, early diagnosis of latent tuberculosis infection (LTBI) cases allows recognition and better control of the tuberculosis pandemic. Materials and Methods: The current tuberculosis screening guidelines as recommended by the World Health Organization, chest X-ray and tuberculin skin test were assessed and revealed rises in TB morbidity and fatality trends in the Kuwait population (low incidence country). In order to evaluate options for LTBI diagnosis, the current work implemented a 4-month prospective, observational, repeated-measure and randomly implemented survey on 180 new immigrants to Kuwait using a structured risk factor questionnaire whilst, simultaneously evaluating the performance of the two standard diagnostics (chest X-ray and tuberculin skin test) with the new biomarker interferon gamma release assays (T-SPOT .TB test and QuantiFERON Gold In-Tube test (QNF-GIT)); which detect the release of interferon gamma (INF-γ) released from sensitization to specific MTB antigens. Results: Associations between various epidemiological risk factors - such as socio-demographic status, smoking and environmental exposure-contact - were associated in the laboratory diagnosed LTBI participants. Positive identification of LTBI prevalence detected by two radiologists was 10.1% having ‘moderate’ inter-reader agreement (Kappa = 0.505), compared to no positives being detected by three pulmonologists. TST results were negative (less than 10-mm ‘cut-off’) even in the 86.1% Bacillus Calmette-Guérin vaccinated expatriates. Estimated LTBI using QNFGIT was 28.3% compared to 41.1% positive T-SPOT .TB test. Both interferon gamma assays revealed concordant ‘abnormal’ results in 26.1% with ‘good’ agreement (kappa = 0.627). Conclusion: Detection of latent tuberculosis infection can be facilitated by introducing evidence-based diagnostic classification depending on history taking of epidemiological-related risk factors and chest X-ray plus either interferon gamma assays.

Thesis (MSc)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: Please see fulltext for abstract. / AFRIKAANSE OPSOMMING: Tuberkulose (TB) affekteer die hele wêreld, maar dit is veral in ontwikkelende lande 'n groot probleem. In Suid-Afrika, soos in baie ander lande, veroorsaak die immuun-paraliserende uitwerking van HIV -koïnfeksie dat die TB-epidemie voortwoeker. Daar is bewyse dat genetiese faktore in die gasheer die uitkoms van die siekte bepaal, aangesien slegs 10% van die individue wat deur Mycobacterium tuberculosis (M tuberculosis) geïnfekteer word, uiteindelik die aktiewe siekte ontwikkel. Die aangebore immuunsisteem is die liggaam se eerste verdedigingslinie, waarna die verworwe immuunreaksie geïnisieer word. Die bakterium se lotgevalle word moontlik bepaal in hierdie vroeë stadium pas nadat dit ingeasem is. Die kollektien-molekule is veral in die long 'n belangrike deel van die aangebore immuunrespons en sluit die mannose-bindende lektien en die surfaktantproteïene A (SP-A) en D (SP-D) in. Dit is al aangetoon dat hierdie drie kollektien-molekule in die gasheer 'n rol speel in die verdediging teen M tuberculosis. In hierdie ondersoek is veral klem gelê op die surfaktantproteïene, wat voorkom asof dit belangrike en kenmerkende rolle speel in die reaksie teen die ingeasemde bakterieë. SP-A versterk die aanhegting van M tuberculosis aan die alveolêre makrofage en verhoog fagositose, terwyl SP-D die bakterieë agglutineer en so verhoed dat dit deur die makrofage gefagositeer word. Gekontroleerde assosiasiestudies in pasiënte is gedoen deur polimorfismes in hierdie gene, wat geassosieer is met TB in ander bevolkings as ons eie, te bestudeer. 'n Polimorfisme in die amino-terminaal area van die SP-D-geen is positief geassosieer met vatbaarheid vir TB. 'n Familie-gebaseerde studie is ook gedoen om die resultate van die gekontroleerde assosiasiestudie te repliseer. Verskillende resultate is verkry en word moontlik bepaal deur die familiestruktuur wat gebruik is. Die aantal families wat bestudeer is, was relatief min en daarom kan daar nie afgelei word dat die assosiasie wat voorheen waargeneem is vals is nie. 'n Groter studie sal gedoen moet word. Die impak van hierdie polimorfisme is verder ondersoek om te bepaal of dit die totale struktuur van die proteïen beïnvloed. Die effekte van hierdie polimorfisme op die konsentrasie van SP-D in die serum van aktiewe TB-pasiënte is ondersoek en vergelyk met die van kontroles. Ons kon nie vasstel watter rol, indien enige, die polimorfisme in die totale struktuur van die SP-D-molekule speel nie, maar ons het bewys dat die serumkonsentrasie van SP-D beduidend verhoog was in aktiewe TB-pasiënte in vergelyking met kontroles (p < 0.0001). Verder het ons ook gedemonstreer dat die konsentrasie van SP-D beduidend verhoog was in die IT-genotipe van die aktiewe TB pasiënte vergeleke met die kontroles (p < 0.0001). Die IT-genotipe is al voorheen positief geassosieer met vatbaarheid vir TB (T. Roos, ongepubliseerde inligting). Verskeie alleliese variante is geïdentifiseer in die SP-A-gene (SP-A1 en SP-A2) wat saam die volle funksionele SP-A-proteïen vorm. Polimorfismes wat onlangs in die kollageen-agtige area van SP-A 1 en SP-A2 gevind is (Madan et al., 2002) en een nuwe polimorfisme wat in hierdie studie geïdentifiseer is, is ondersoek in 'n Suid-Afrikaanse bevolking. Ons het beduidende positiewe assosiasie tussen 'n polimorfisme in die kollageen-agtige area van die SP-A2 geen en vatbaarheid vir TB (p = 0.007) aangetoon. Ons bevindinge bewys die belangrikheid van die bestudering van mensgenetika, wat die immuunkompetensie rig, om vatbaarheid vir infektiewe siektes te verstaan.