Exploring the Genetic Landscape of Mycobacterium tuberculosis: Unlocking the Differences in Between Latent and Active Tuberculosis

Background: Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), can enter a dormant phase within host tissues, complicating treatment and highlighting the need to investigate the genetic changes associated with dormancy. Methods: This study examined clinical isolates of MTB, representing...

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Main Authors: Ali Akbar Velayati, Satoshi Mitaria, Parissa Farnia, Poopak Farnia, Jaladein Ghanavi, Mohsan Maleknia, Yoshiro Murase, Sven Hoffner
Format: Article
Language:English
Published: Wolters Kluwer Medknow Publications 2024-12-01
Series:International Journal of Mycobacteriology
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Online Access:https://journals.lww.com/10.4103/ijmy.ijmy_212_24
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author Ali Akbar Velayati
Satoshi Mitaria
Parissa Farnia
Poopak Farnia
Jaladein Ghanavi
Mohsan Maleknia
Yoshiro Murase
Sven Hoffner
author_facet Ali Akbar Velayati
Satoshi Mitaria
Parissa Farnia
Poopak Farnia
Jaladein Ghanavi
Mohsan Maleknia
Yoshiro Murase
Sven Hoffner
author_sort Ali Akbar Velayati
collection DOAJ
description Background: Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), can enter a dormant phase within host tissues, complicating treatment and highlighting the need to investigate the genetic changes associated with dormancy. Methods: This study examined clinical isolates of MTB, representing a range of susceptibility profiles and standard reference laboratory strains, i.e., H37Rv and Mycobacterium bovis bacillus Calmette–Guérin. Each strain was subcultured in a controlled laboratory environment to analyze two distinct phases: one maintained in vitro under a double-stress dormancy model using the Wayne model (characterized by the absence of oxygen and nutrients) for 12 months, and the other examined during its exponential growth phase. Whole-genome sequencing and protein structure analysis using bioinformatics tools were performed to characterize and compare mutations in isolates at each phase. Results: Three distinct frameshift mutations were identified in the fbiC, PPE35, and ald genes, and one upstream mutation in whiB6 genes in all studied isolates under dormancy, irrespective of their susceptibility patterns (P < 0.01). Among drug-resistant strains, at the exponential phase isolated from patients with prolonged treatment, 5%–7% had PPE35, ald mutations, whereas 95% had the whiB6 mutation, suggesting that adaptive stress responses may be triggered under in vivo conditions. Conclusions: The newly identified frameshift mutations (fbiC, PPE35, and ald genes), consistently found in both laboratory and clinical isolates, seem to play a critical role in the survival of MTB during dormancy. Based on these findings, designing a molecular test to differentiate between active and latent TB possibly enables timely prophylactic interventions.
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spelling doaj-art-e7abeaa8ff0c41038ac1c6c6b60ac8fb2025-01-07T06:19:07ZengWolters Kluwer Medknow PublicationsInternational Journal of Mycobacteriology2212-55312212-554X2024-12-0113441041910.4103/ijmy.ijmy_212_24Exploring the Genetic Landscape of Mycobacterium tuberculosis: Unlocking the Differences in Between Latent and Active TuberculosisAli Akbar VelayatiSatoshi MitariaParissa FarniaPoopak FarniaJaladein GhanaviMohsan MalekniaYoshiro MuraseSven HoffnerBackground: Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), can enter a dormant phase within host tissues, complicating treatment and highlighting the need to investigate the genetic changes associated with dormancy. Methods: This study examined clinical isolates of MTB, representing a range of susceptibility profiles and standard reference laboratory strains, i.e., H37Rv and Mycobacterium bovis bacillus Calmette–Guérin. Each strain was subcultured in a controlled laboratory environment to analyze two distinct phases: one maintained in vitro under a double-stress dormancy model using the Wayne model (characterized by the absence of oxygen and nutrients) for 12 months, and the other examined during its exponential growth phase. Whole-genome sequencing and protein structure analysis using bioinformatics tools were performed to characterize and compare mutations in isolates at each phase. Results: Three distinct frameshift mutations were identified in the fbiC, PPE35, and ald genes, and one upstream mutation in whiB6 genes in all studied isolates under dormancy, irrespective of their susceptibility patterns (P < 0.01). Among drug-resistant strains, at the exponential phase isolated from patients with prolonged treatment, 5%–7% had PPE35, ald mutations, whereas 95% had the whiB6 mutation, suggesting that adaptive stress responses may be triggered under in vivo conditions. Conclusions: The newly identified frameshift mutations (fbiC, PPE35, and ald genes), consistently found in both laboratory and clinical isolates, seem to play a critical role in the survival of MTB during dormancy. Based on these findings, designing a molecular test to differentiate between active and latent TB possibly enables timely prophylactic interventions.https://journals.lww.com/10.4103/ijmy.ijmy_212_24alddormant tuberculosisexponential phasefbicppe35
spellingShingle Ali Akbar Velayati
Satoshi Mitaria
Parissa Farnia
Poopak Farnia
Jaladein Ghanavi
Mohsan Maleknia
Yoshiro Murase
Sven Hoffner
Exploring the Genetic Landscape of Mycobacterium tuberculosis: Unlocking the Differences in Between Latent and Active Tuberculosis
International Journal of Mycobacteriology
ald
dormant tuberculosis
exponential phase
fbic
ppe35
title Exploring the Genetic Landscape of Mycobacterium tuberculosis: Unlocking the Differences in Between Latent and Active Tuberculosis
title_full Exploring the Genetic Landscape of Mycobacterium tuberculosis: Unlocking the Differences in Between Latent and Active Tuberculosis
title_fullStr Exploring the Genetic Landscape of Mycobacterium tuberculosis: Unlocking the Differences in Between Latent and Active Tuberculosis
title_full_unstemmed Exploring the Genetic Landscape of Mycobacterium tuberculosis: Unlocking the Differences in Between Latent and Active Tuberculosis
title_short Exploring the Genetic Landscape of Mycobacterium tuberculosis: Unlocking the Differences in Between Latent and Active Tuberculosis
title_sort exploring the genetic landscape of mycobacterium tuberculosis unlocking the differences in between latent and active tuberculosis
topic ald
dormant tuberculosis
exponential phase
fbic
ppe35
url https://journals.lww.com/10.4103/ijmy.ijmy_212_24
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