Whole genome sequencing based differentiation between re-infection and relapse in Indian patients with tuberculosis recurrence, with and without HIV co-infection

Introduction: Differentiation between relapse and reinfection in cases with tuberculosis (TB) recurrence has important implications for public health, especially in patients with human immunodeficiency virus (HIV) co-infection. We compared Mycobacterial Interspersed Repeat Unit (MIRU) typing and spoligotyping with whole genome sequencing (WGS) to differentiate between relapse and reinfection in patients (HIV-positive and HIV-negative) with TB recurrence. We also assessed the value of WGS to track acquired drug resistance in those with relapse after successful treatment. Method: Forty-one paired M. tuberculosis isolates collected from 20 HIV-positive and 21 HIV-negative patients were subjected to WGS in addition to spoligotyping and MIRU typing. Phylogenetic and Single Nucleotide Substitution (SNP) clustering analyses were performed to determine whether recurrences were due to relapse or re-infection. Results: Comparison of M. tuberculosis genomes indicated that 95% of TB recurrences in the HIV-negative cohort were due to relapse, while the majority of TB recurrences (75%) in the HIV-positive cohort was due to reinfection (P = 0.0001). New drug resistance mutations were acquired in 5/24 cases (20.8%) that experienced relapse. Conclusions: WGS provided increased resolution, but differentiation between relapse and reinfection was broadly consistent with MIRU and spoligotyping. The high contribution of reinfection among HIV infected patients experiencing TB recurrence warrants further study to explore risk factors for TB exposure. (C) 2021 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.

Automated summary

This study compared the efficacy of MIRU typing, spoligotyping, and WGS in differentiating between relapse and reinfection in TB recurrence cases. The majority of TB recurrences in HIV-positive patients were due to reinfection, while in HIV-negative patients, relapse was the main cause. WGS provided higher resolution, but the results were consistent with MIRU and spoligotyping.