Surveillance of Daughter Micronodule Formation Is a Key Factor for Vaccine Evaluation Using Experimental Infection Models of Tuberculosis in Macaques

Tuberculosis (TB) is still a major worldwide health problem and models using non-human primates (NHP) provide the most relevant approach for vaccine testing. In this study, we analysed CT images collected from cynomolgus and rhesus macaques following exposure to ultra-low dose Mycobacterium tuberculosis (Mtb) aerosols, and monitored them for 16 weeks to evaluate the impact of prior intradermal or inhaled BCG vaccination on the progression of lung disease. All lesions found (2553) were classified according to their size and we subclassified small micronodules (<4.4 mm) as 'isolated', or as 'daughter', when they were in contact with consolidation (described as lesions ≥ 4.5 mm). Our data link the higher capacity to contain Mtb infection in cynomolgus with the reduced incidence of daughter micronodules, thus avoiding the development of consolidated lesions and their consequent enlargement and evolution to cavitation. In the case of rhesus, intradermal vaccination has a higher capacity to reduce the formation of daughter micronodules. This study supports the 'Bubble Model' defined with the C3HBe/FeJ mice and proposes a new method to evaluate outcomes in experimental models of TB in NHP based on CT images, which would fit a future machine learning approach to evaluate new vaccines

Disseminated tuberculosis and diagnosis delay during the COVID-19 era in a Western European country : a case series analysis

Disseminated tuberculosis is frequently associated with delayed diagnosis and a poorer prognosis. To describe case series of disseminated TB and diagnosis delay in a low TB burden country during the COVID-19 period. We consecutively included all patients with of disseminated TB reported from 2019 to 2021 in the reference hospital of the Northern Crown of the Metropolitan Area of Barcelona. We collected socio-demographic information, clinical, laboratory and radiological findings. We included all 30 patients reported during the study period-5, 9, and 16 in 2019, 2020, and 2021 respectively-20 (66.7%) of whom were male and whose mean age was 41 years. Twenty-five (83.3%) were of non-EU origin. The most frequent system involvement was central nervous system (N = 8; 26.7%) followed by visceral (N = 7; 23.3%), gastro-intestinal (N = 6, 20.0%), musculoskeletal (N = 5; 16.7%), and pulmonary (N = 4; 13.3%). Hypoalbuminemia and anemia were highly prevalent (72 and 77%). The median of diagnostic delay was 6.5 months (IQR 1.8-30), which was higher among women (36.0 vs. 3.5 months; p = 0.002). Central nervous system involvement and pulmonary involvement were associated with diagnostic delay among women. We recorded 24 cured patients, two deaths, three patients with post-treatment sequelae, and one lost-to-follow up. We observed a clustering effect of patients in low-income neighborhoods (p < 0.001). There was a substantial delay in the diagnosis of disseminated TB in our study region, which might impacted the prognosis with women affected more negatively. Our results suggest that an increase in the occurrence of disseminated TB set in motion by diagnosis delay may have been a secondary effect of the COVID-19 pandemic

Corrigendum : Disseminated tuberculosis and diagnosis delay during the COVID-19 era in a Western European country: a case series analysis

Disseminated tuberculosis is frequently associated with delayed diagnosis and a poorer prognosis. To describe case series of disseminated TB and diagnosis delay in a low TB burden country during the COVID-19 period. We consecutively included all patients with of disseminated TB reported from 2019 to 2021 in the reference hospital of the Northern Crown of the Metropolitan Area of Barcelona. We collected socio-demographic information, clinical, laboratory and radiological findings. We included all 30 patients reported during the study period-5, 9, and 16 in 2019, 2020, and 2021 respectively-20 (66.7%) of whom were male and whose mean age was 41 years. Twenty-five (83.3%) were of non-EU origin. The most frequent system involvement was central nervous system (N = 8; 26.7%) followed by visceral (N = 7; 23.3%), gastro-intestinal (N = 6, 20.0%), musculoskeletal (N = 5; 16.7%), and pulmonary (N = 4; 13.3%). Hypoalbuminemia and anemia were highly prevalent (72 and 77%). The median of diagnostic delay was 6.5 months (IQR 1.8-30), which was higher among women (36.0 vs. 3.5 months; p = 0.002). Central nervous system involvement and pulmonary involvement were associated with diagnostic delay among women. We recorded 24 cured patients, two deaths, three patients with post-treatment sequelae, and one lost-to-follow up. We observed a clustering effect of patients in low-income neighborhoods (p < 0.001). There was a substantial delay in the diagnosis of disseminated TB in our study region, which might impacted the prognosis with women affected more negatively. Our results suggest that an increase in the occurrence of disseminated TB set in motion by diagnosis delay may have been a secondary effect of the COVID-19 pandemic

Estudio de la tuberculosis pulmonar mediante tomografía computarizada multidetector en un modelo experimental de minipig

La tuberculosis es todavía, un gran problema de salud pública a nivel mundial. Según el último informe de la OMS, el año 2015 hubieron 10,5 millones de casos nuevos, y hasta 1,8 millones de personas murieron de tuberculosis. En Cataluña, cada año hay 1200 casos nuevos, de los cuales la mayoría se concentran en la Ciudad de Barcelona. A nivel profiláctico, existe una única vacuna, la BCG, con una efectividad variable según poblaciones, y que no protege de las formas pulmonares adultas. Es por esto que, en los últimos años, se han dedicado grandes recursos al desarrollo de nuevos candidatos a vacuna, que son testados sistemáticamente en modelos experimentales animales. En el marco de un proyecto europeo, la Unitat Unitat de Tuberculosi Experimental de la Fundació Germans Trias i Pujol, ha evaluado la eficacia de 3 candidatos en un modelo experimental de tuberculosis en minipig, comparados con el grupo control no vacunado. La hipótesis de esta tesis era que la evaluación mediante TC multidetector es útil para describir el curso de la TB en el modelo experimental de minipig, y para evaluar el efecto de candidatos a vacuna sobre este curso. Se plantearon 3 objetivos: 1) Definir un protocolo técnico adecuado para el estudio post-necropsia del pulmón y árbol traqueo-bronquial del minipig; 2) Determinar las características radiológicas mediante TB multidetector de las lesiones derivades de la infección tuberculosa en el modelo experimental de tuberculosis en el minipig; y 3) Evaluar mediante TB multidetector el efecto de nuevos candidatos a vacuna en el curso de la tuberculosis en el modelo experimental de minipig. Con esta finalidad, se utilizaron 24 paquetes broncopulmonares extraídos del proyecto de la Unitat de Tuberculosi Experimental, y se sometieron a TC multidector. Las imágenes, una vez ajustadas las características técnicas y con la ayuda del grupo MOSIMBIO de la Universitat Politècnica de Catalunya (UPC), se analizaron minuciosamente y se anotaron, de cada minipig, los siguientes datos sobre las lesiones tuberculosas detectadas: número de lesiones, localitzación, tamaño, Unidades Houndsfield, distancia entre las lesiones. En una segunda fase, se realizó una correlación entre la semiología radiológica de les imágenes obtenidas y el estudio histopatológico de las muestras. En cuanto a resultados, no se observaron diferencias significativas en la morfología y la anatomía broncopulmonar de todos los especímenes estudiados. En todos menos un minipig se detectó afectación pulmonar unilateral, y atribuimos las diferencias encontradas a la infección inicial y no a la pertenencia a un grupo experimental determinado. La mayoría (96,2%) de lesiones tuberculosas se localizaron en los lóbulos caudados. El 5% de las lesiones detectadas, se agrupaban en clústeres de un mínimo de dos lesiones. No se encontraron diferencias significativas entre los distintos grupos experimentales en cuanto a la distribución de las lesiones en el plano sagital, antero-posterior o cráneo-caudal. Un 20-25% de las lesiones estaban en contacto con la pleura, sin encontrarse diferencias significativas entre los grupos experimentales. El número de lesiones encontradas en el grupo control no vacunado fue menor que en los grupos vacunados, y eran de menor tamaño. Sin embargo, los grupos sometidos a vacunación mostraron una mayor calcificación de las lesiones, medida por Unidades Houndsfield de más de 120 (25% del total de las lesiones del grupo control vs 66% del del grupo de vacunados). En cuanto a la correlación con la histopatología, el TC Multidetector detecta más lesiones que la histopatología, pero es menos sensible en cuanto a clasificar las mismas. Como conclusión, este trabajo de tesis confirma la utilidad del TCMD como herramienta diagnóstica apropiada para evaluar nuevas estrategias terapéuticas y profilácticas en modelos experimentales animales de tuberculosis o en humanos.Nowadays, tuberculosis is still an important Public Health problem at worldwide level. According to the last WHO report, on 2015, there were 10.5 million of new cases, and up to 1.8 million people died from tuberculosis. In Catalonia, there are 1200 new cases each year, most of them diagnosed in Barcelona city. At prophylactical level, there is only one available vaccine, the BCG, with a variable effectivity according to populations, and not protecting adults from pulmonary forms. Lots of resources have been devoted to the development of new vaccine candidates, systematically tested in experimental animal models. In the context of an european project, the Experimental Tuberculosis Unit of the Germans Trias i Pujol Foundation evaluated the efficacy of 3 vaccine candidates in a experimental model of tuberculosis using minipigs, comparing them to the unvaccinated control group. The hypothesis of the present thesis work was that the evaluation by multidetector TC is useful to describe the course of tuberculosis in a minipig experimental model, and to evaluate the effect of new vaccine candidates on this course. Up to 3 objectives were set up: 1) To define an adequate technical protocol to study post-necropsia the lung and tracheo-bronchial tree of the minipig; 2) To determine the radiologic characteristics by multidetector TC of tuberculous lesions in a minipig experimental model; and 3) To evaluate by multidetector TC the effect of new vaccine candidates in the course of tuberculosis infection in a minipig experimental model. With this aim, the broncho-pulmonary pieces of 24 minipigs were used, all collected within the Experimental Tuberculosis Unit’s project, and analyzed by multidetector TC. Once the technical characteristics adjusted, and with the help of the MOSIMBIO group of the Politecnic University of Catalunya (in catalan, UPC), the images were analyzed. From each minipig, the following data of the tuberculous lesions were recorded: number of lesions, localization, size, Houndsfield Units, distance between lesions. In a secondary phase, a correlation between the radiologic semiology of the images obtained and the histopathological study of the samples was done. No statistically significant differences were observed between specimens in terms of morphology and anatomy. In all but one minipig unilateral lug affectation was found, and we attribute the differences encountered to the initial infection and not to the different experimental groups. The majority (96.2%) of tuberculous lesions were localized in caudal lobes. The 5% of the detected lesions were grouped in clusters of minimum 2 lesions. No statistically significant differences were found between the experimental groups according to the distribution in sagital, antero-posterior or craneo-caudal spacial planes. A 20-25% of the lesions were in contact with the pleura, with no statistically significant differences encountered between the experimental groups. The number of lesions detected in the unvaccinated control group was lower than in vaccinated groups, and had smaller sizes. However, the vaccinated animals showed a higher percentage of calcification in their lesions, measured as Houndsfield Units of more than 120 (25% of total lesions from the control group vs 66% of those from the vaccinated groups). On the correlation with the histopathology, the Multidetector TC detected more lesions than the histopathology analysis, but was less sensitive in classifying them. As conclusion, this thesis work confirms the usefulness of the MultiDetector TC as an useful diagnostic tool to evaluate new therapeutical and prophylactical strategies in experimental animal models of tuberculosis or in humans

Surveillance of Daughter Micronodule Formation Is a Key Factor for Vaccine Evaluation Using Experimental Infection Models of Tuberculosis in Macaques

Tuberculosis (TB) is still a major worldwide health problem and models using non-human primates (NHP) provide the most relevant approach for vaccine testing. In this study, we analysed CT images collected from cynomolgus and rhesus macaques following exposure to ultra-low dose Mycobacterium tuberculosis (Mtb) aerosols, and monitored them for 16 weeks to evaluate the impact of prior intradermal or inhaled BCG vaccination on the progression of lung disease. All lesions found (2553) were classified according to their size and we subclassified small micronodules (&lt;4.4 mm) as &lsquo;isolated&rsquo;, or as &lsquo;daughter&rsquo;, when they were in contact with consolidation (described as lesions &ge; 4.5 mm). Our data link the higher capacity to contain Mtb infection in cynomolgus with the reduced incidence of daughter micronodules, thus avoiding the development of consolidated lesions and their consequent enlargement and evolution to cavitation. In the case of rhesus, intradermal vaccination has a higher capacity to reduce the formation of daughter micronodules. This study supports the &lsquo;Bubble Model&rsquo; defined with the C3HBe/FeJ mice and proposes a new method to evaluate outcomes in experimental models of TB in NHP based on CT images, which would fit a future machine learning approach to evaluate new vaccines

Modelling the dynamics of tuberculosis lesions in a virtual lung: role of the bronchial tree in endogenous reinfection

Tuberculosis (TB) is an infectious disease that still causes more than 1.5 million deaths annually. The World Health Organization estimates that around 30% of the world’s population is latently infected. However, the mechanisms responsible for 10% of this reserve (i.e., of the latently infected population) developing an active disease are not fully understood, yet. The dynamic hypothesis suggests that endogenous reinfection has an important role in maintaining latent infection. In order to examine this hypothesis for falsifiability, an agent-based model of growth, merging, and proliferation of TB lesions was implemented in a computational bronchial tree, built with an iterative algorithm for the generation of bronchial bifurcations and tubes applied inside a virtual 3D pulmonary surface. The computational model was fed and parameterized with computed tomography (CT) experimental data from 5 latently infected minipigs. First, we used CT images to reconstruct the virtual pulmonary surfaces where bronchial trees are built. Then, CT data about TB lesion’ size and location to each minipig were used in the parameterization process. The model’s outcome provides spatial and size distributions of TB lesions that successfully reproduced experimental data, thus reinforcing the role of the bronchial tree as the spatial structure triggering endogenous reinfection. A sensitivity analysis of the model shows that the final number of lesions is strongly related with the endogenous reinfection frequency and maximum growth rate of the lesions, while their mean diameter mainly depends on the spatial spreading of new lesions and the maximum radius. Finally, the model was used as an in silico experimental platform to explore the transition from latent infection to active disease, identifying two main triggering factors: a high inflammatory response and the combination of a moderate inflammatory response with a small breathing amplitude.Peer Reviewe

Disseminated tuberculosis and diagnosis delay during the COVID-19 era in a Western European country: a case series analysis

BackgroundDisseminated tuberculosis is frequently associated with delayed diagnosis and a poorer prognosis.ObjectivesTo describe case series of disseminated TB and diagnosis delay in a low TB burden country during the COVID-19 period.MethodologyWe consecutively included all patients with of disseminated TB reported from 2019 to 2021 in the reference hospital of the Northern Crown of the Metropolitan Area of Barcelona. We collected socio-demographic information, clinical, laboratory and radiological findings.ResultsWe included all 30 patients reported during the study period—5, 9, and 16 in 2019, 2020, and 2021 respectively—20 (66.7%) of whom were male and whose mean age was 41 years. Twenty-five (83.3%) were of non-EU origin. The most frequent system involvement was central nervous system (N = 8; 26.7%) followed by visceral (N = 7; 23.3%), gastro-intestinal (N = 6, 20.0%), musculoskeletal (N = 5; 16.7%), and pulmonary (N = 4; 13.3%). Hypoalbuminemia and anemia were highly prevalent (72 and 77%). The median of diagnostic delay was 6.5 months (IQR 1.8–30), which was higher among women (36.0 vs. 3.5 months; p = 0.002). Central nervous system involvement and pulmonary involvement were associated with diagnostic delay among women. We recorded 24 cured patients, two deaths, three patients with post-treatment sequelae, and one lost-to-follow up. We observed a clustering effect of patients in low-income neighborhoods (p &lt; 0.001).ConclusionThere was a substantial delay in the diagnosis of disseminated TB in our study region, which might impacted the prognosis with women affected more negatively. Our results suggest that an increase in the occurrence of disseminated TB set in motion by diagnosis delay may have been a secondary effect of the COVID-19 pandemic