Optimisation of the diagnosis and improvement of the treatment of tuberculosis: Summary of the habitation thesis in medical sciences: 321.07 – Phthisiopneumology

Abstract

Thesis structure: introduction, six chapters, conclusions, bibliography containing 307 sources, 29 figures, 17 tables, results of the study were published in 51 scientific papers. Keywords: TB, MDR, laboratory diagnosis, M. tuberculosis, antituberculosis treatment. Field of study: General medicine. Pulmonology. Research aim: Evaluation of clinical and laboratory interventions with the potential to optimise diagnosis and to improve treatment of tuberculosis patients. Research objectives: To assess efficacy of determination of the interferon-γ and interleukin-2 peripheral cell response in differentiating the clinical statuses of M. tuberculosis infection; To assess the diagnostic accuracy of automated reading by Fluorobot platform of the fluorescent stained smears in the diagnosis of pulmonary tuberculosis in adults; To determine the impact of the implementation of GeneXpert MTB/Rif technique, on the therapeutic management of patients with mutlidrug-resistant pulmonary tuberculosis in the Republic of Moldova; To determine the added value of the bronchial aspirate specimen testing in the diagnosis of pulmonary tuberculosis in patients with paucibacillary free expectorated sputum specimens; To assess the effectiveness of including bedaquiline in multidrugresistant tuberculosis treatment regimens in the conditions of programmatic management of tuberculosis patients; To assess the rationality of including high-dose isoniazid in treatment regimens used in patients with multidrug-resistant tuberculosis in the Republic of Moldova; To determine the impact of respiratory function, assessed at diagnosis, on treatment outcomes in patients with pulmonary tuberculosis; To evaluate alternative approaches in assessment of treatment outcomes in tuberculosis patients. Scientific novelty and originality. The novelty of the research is given by the evaluation of the efficacy of applying new biomarkers (IL-2/INF-γ cytokine profile of peripheral blood lymphocytes), alternative specimens (bronchial aspirate) and original technological solutions (FluoroSpot, Fluorobot, Xpert MTB/Rif) for the diagnosis of tuberculosis in clinical practice. Similarly, the novelty of the study is ensured by the assessment of the effectiveness and/or rationality of the application in routine clinical conditions in the healthcare system of the Republic of Moldova of new drugs such as bedaquiline or high-dose isoniazid, together with the identification of new predictors of the effectiveness of antituberculosis treatment and the application of more objective approaches, from a clinical point of view, in the assessment of antituberculosis treatment outcomes. Results that led to the solution of a major scientific or applied problem. Fluorospot represents an alternative method for the diagnosis of latent tuberculosis infection with a diagnostic accuracy like that of EliSpot-IGRA techniques; Application of deep learning algorithm-based technologies such as Fluorobot allows automated reading of microscopic smears in fluorescent staining with an accuracy comparable to that obtained at manual reading; Nationwide application of the Xpert MTB/Rif technique in the diagnosis of tuberculosis has allowed a 6-fold reduction in therapeutic delay in patients with MDR pulmonary tuberculosis; The use of bronchial aspirate specimens tested by molecular-genetic tests (Xpert MTB/Rif) in patients with pulmonary tuberculosis with highly paucibacillary sputum (microscopy and Xpert MTB/Rif negative) allows additional microbiological confirmation in a quarter of these patients; Bedaquiline used in treatment regimens in patients with MDR tuberculosis, including those with previous treatment failure, under programmatic care delivery ensures a high cure rate and reduced mortality; Resistance to isoniazid in MDR tuberculosis patients in the Republic of Moldova is overwhelmingly due to mutations in the katG gene (associated with high levels of minimum inhibitory concentrations against this drug), which precludes empirical administration of high doses of isoniazid (15-20 mg/kg) in treatment regimens for these patients; Restrictive pattern of pulmonary function in patients with pulmonary tuberculosis, assessed at initiation of antituberculosis treatment, is a potentially modifiable predictor of negative treatment outcome in patients with pulmonary tuberculosis; Assessment of antituberculosis treatment outcome after a period of post-therapy surveillance is a more rational approach to antituberculosis treatment evaluation, feasible in conditions of programmatic care of tuberculosis patients. Theoretical significance. The research provides the rationale on optimisation of current diagnostic algorithms on diagnosis of M. tuberculosis infection by potentially including serological assays to assess INF-γ and IL-2 secreted by T lymphocytes, automated reading of microscopy of fluorescent stained smears and molecular-genetic testing of bronchial aspirate specimens in patients with paucibacillary sputum. Argumentation of the usefulness of the mentioned interventions is performed considering sensitivity, specificity, positive and negative likelihood ratios. Similarly, the impact of the nationwide implementation of the Xpert MTB/Rif technique has been argued by assessing the overall effect on reducing therapeutic delay in patients with MDR pulmonary tuberculosis. As part of the valuation of interventions for the improvement of tuberculosis treatment, was argued the effectiveness of including bedaquiline in treatment regimens under programmatic conditions in MDR-TB patients by demonstrating a higher cure rate and lower mortality when using this drug, and the ineffectiveness of empirical inclusion (without assessment of genetic determinants) of high-dose isoniazid in treatment regimens in MDR tuberculosis patients. In the same context, the rationality and feasibility of post-therapy surveillance in assessing TB treatment outcomes was argued. Applicative value. The application of the interventions evaluated in this work allows to reduce the diagnostic delay in patients with MDR pulmonary tuberculosis, significantly to increase the microbiological confirmation of pulmonary tuberculosis in patients with paucibacillary sputum, and to optimize the reading of fluorescent stained smears. Likewise, the use of the evaluated therapeutic solutions has been shown to be effective in increasing cure rate and reducing mortality rate in MDR tuberculosis patients, as well as avoiding irrational empirical use of high-dose isoniazid treatments with potential hepatotoxic effect in these patients. The use of treatment assessment after post-treatment surveillance have been shown to be more rational, from clinical point of view, for the assessment of therapeutic efficacy. Implementation of scientific results. The theoretical and practical results of the study are used in training of medical students at the Department of Pulmonology and Allergology, as well as in the clinical departments of "Chiril Draganiuc" Phtisiopneumology Institute. There were registered 3 certificates of innovator and 3 acts of implementation of results.