Tuberculosis-HIV Co-Infection: Progress and Challenges After Two Decades of Global Antiretroviral Treatment Roll-Out

Epidemiological characteristics of extrapulmonary tuberculosis patients with or without pulmonary tuberculosis

Our study aimed to investigate the epidemiology of extrapulmonary tuberculosis (EPTB) and analyse the epidemiological characteristics of EPTB patients with or without pulmonary tuberculosis (PTB). EPTB cases admitted in our hospital from January 2015 to December 2020 were included. Uni- and multi-variable logistic regression analysis was carried out to identify risk factors and prognostic factors of concomitant EPTB and PTB or exclusively EPTB. A total of 3488 EPTB patients were reviewed, including 2086 patients with concurrent PTB and EPTB, and 1402 patients with exclusively EPTB. Logistic regression analysis showed that age >60 years (OR = 1.674, 95% CI = 1.438–1.949, P < 0.001) and female (OR = 1.325, 95% CI = 1.155–1.520, P < 0.001) were risk factors of exclusively EPTB, while co-morbidities (OR = 0.676, 95% CI = 0.492–0.929, P = 0.016) and severe symptoms (OR = 0.613, 95% CI = 0.405–0.929, P = 0.021) were risk factors for concurrence of EPTB and PTB. Age >60 years was an independent prognostic factor in EPTB patients with or without PTB (HR = 11.059, 95%CI = 5.097–23.999, P < 0.001; HR = 23.994, 95%CI = 3.093–186.151, P = 0.0020). Female gender was an independent prognostic factor in patients with concurrent PTB and EPTB (HR = 23.994, 95%CI = 3.093–186.151, P = 0.002). Our study disclosed the differential epidemiological characteristics of EPTB patients with or without PTB in China.

Atomic structure of the regulatory TGS domain of Rel protein from Mycobacterium tuberculosis and its interaction with deacylated tRNA

The stringent response is critical for the survival of Mycobacterium tuberculosis (Mtb) under nutrient starvation. The mechanism is mediated by a GTP pyrophosphokinase known as Rel, containing N-terminal synthetase and hydrolase domains and C-terminal regulatory domains, which include the TGS domain (ThrRS, GTPase, and SpoT proteins) that has been proposed to activate the synthetase domain via interaction with deacylated tRNA. Here, we present the NMR solution structure of the Mtb Rel TGS domain (MtRel TGS), consisting of five antiparallel β-strands and one helix-loop-helix motif. The interaction of MtRel TGS with deacylated tRNA is shown, indicating the critical amino acids of MtRel TGS in tRNA binding, and presenting the first structural evidence of MtRel TGS binding to deacylated tRNA in solution in the absence of the translational machinery.

Mechanochemical Synthesis and Physicochemical Characterization of Isoniazid and Pyrazinamide Co-crystals With Glutaric Acid

The present work reports two novel pharmaceutical co-crystals; 2:1 isoniazid-glutaric acid (INHGA) and 2:1 pyrazinamide-glutaric acid (PGA). Isoniazid and pyrazinamide are key first-line drugs used for the treatment of tuberculosis. The co-crystals were produced via solid-state and solvent assisted grinding methods. Thermal characteristics of the samples were obtained using the differential scanning calorimetry, hot stage microscopy, and thermogravimetric analyses. The morphology of the powder samples by scanning electron microscopy, structural analysis by Fourier transform infrared spectroscopy and powder X-rays diffraction ensured co-crystal formation. Thermal analyses confirmed the co-crystals with new melting transitions ranging between their respective starting materials. Unique morphologies of the co-crystal particles were clear in SEM micrographs. The formation of intermolecular interactions with the co-crystal former was confirmed by the FT-IR spectral band shifting and was supported by distinct PXRD patterns of co-crystals thereby authenticating the successful co-crystal formation. In vitro solubility evaluation of the synthesized co-crystals by HPLC suggested a remarkable increase in solubility of both INH and PZA in their respective co-crystals.