Host-pathogen interactions in Multidrug-Resistant Tuberculosis (MDR-TB): Study of the Molecular Epidemiology, Host Immune Responses and Genome-Based Prediction and Early Identification of MDR-TB in High Tuberculosis Burden Settings

The aim of this proposal is to study hostpathogen factors in multidrug-resistant tuberculosis (MDRTB) with the ultimate goal of MDRTB prevention and early detection. We will conduct genotypic characterization of MDRTB clinical isolates and study host immune responses in MDRTB compared with drug-susceptible tuberculosis patients (DSTB) from two TB endemic areas.

The specific objectives of the proposal are:

• Specific objective 1: Conduct a genotypic characterization of MDRTB clinical isolates in Callao, Peru and Minas Gerais, Brazil during a 2 year observational period. MDR profile of clinical isolates will be assessed throughout the novel Mykrobe predictor software application, then MDR strains transmission will be ascertained by 24locus mycobacterial interspersed repetitive unitsvariable number of tandem repeats (MIRUVNTR) of clinical isolates with MDRTB in each region. The novel software tool PhyloResistance Search Engine (PhyResSE) will be used to delineating both lineage and resistance data using whole genome sequencing (WGS) data.
• Specific objective 2: Characterization of the role of mycobacterial small regulatory RNAs (sRNAs) in the development of Reference: drug resistance in M. tuberculosis. WGS data generated and analyzed in Objective 1 will allow identifying mycobacterial sRNAs mutated in drug-resistant isolates as novel genetic markers of drug resistance.
• Specific objective 3: Determine if MDRTB strains are capable of generating a dysfunctional immune response during MDRTB progression. We will analyze key cytokines as well as lipid mediators and perform leukocyte immune-phenotyping of HIVnegative patients with DSTB and MDRTB.

Our results will further validate and allow the implementation of genome-based methods for the prediction and early detection of MDRTB occurrence and transmission in TB endemic areas such as Peru and Brazil, and will generate knowledge of dysfunctional host immune responses that could be used as biomarkers of MDRTB progression and as basis for immunebased therapies to control MDRTB. Furthermore, the results of this project will provide data for future prediction and prevention trials aimed at decreasing the occurrence and related complications of MDRTB in areas with similar TB burden in ERANETLAC.