The COVID-19, tuberculosis and HIV/AIDS: Ménage à Trois

Genetic diversity, evolution and drug resistance of Mycobacterium tuberculosis lineage 2

Mycobacterium tuberculosis causes a chronic infectious disease called tuberculosis. Phylogenetic lineage 2 (L2) of M. tuberculosis, also known as the East Asian lineage, is associated with high virulence, increased transmissibility, and the spread of multidrug-resistant strains. This review article examines the genomic characteristics of the M. tuberculosis genome and M. tuberculosis lineage 2, such as the unique insertion sequence and spoligotype patterns, as well as MIRU-VNTR typing, and SNP-based barcoding. The review describes the geographical distribution of lineage 2 and its history of origin. In addition, the article discusses recent studies on drug resistance and compensatory mechanisms of M. tuberculosis lineage 2 and its impact on the pathogen's transmissibility and virulence. This review article discusses the importance of establishing a unified classification for lineage 2 to ensure consistency in terminology and criteria across different studies and settings.

Colliding Challenges: An Analysis of SARS-CoV-2 Infection in Patients with Pulmonary Tuberculosis versus SARS-CoV-2 Infection Alone

Background and Objectives: The concurrent occurrence of tuberculosis and COVID-19 coinfection poses significant clinical complexities, warranting a nuanced approach to diagnosis, management, and patient care. Materials and Methods: A retrospective, cross-sectional study was conducted on two groups: one comprising 32 patients with pulmonary TB (PTB) and COVID-19 co-infection, and one including 100 patients with COVID-19 alone. Data was collected from medical records, including patient history, clinical parameters, laboratory, imaging results, and patient outcome. Results: A lower BMI emerges as a significant marker suggesting underlying PTB in patients with SARS-CoV-2 co-infection. Type 2 diabetes mellitus increases the risk of death in PTB-SARS-CoV-2 co-infection. Co-infected patients show lymphocytopenia and higher neutrophil levels, CRP, transaminases, and D-dimer levels. Elevated CRP and ALT levels are linked to increased co-infection likelihood. Certain parameters like SpO2, CRP, ALT, AST, and D-dimer effectively differentiate between co-infected and COVID-19 patients. Platelet-to-lymphocyte ratio is notably higher in co-infected individuals. Lesion severity on imaging is significantly associated with co-infection, highlighting imaging's diagnostic importance. Longer hospital stays are linked to co-infection but not significantly to death risk. Conclusions: Certain clinical and biological factors may serve as potential indicators of PTB co-infection in patients with SARS-CoV-2.

Recombinant expression and functional characterization of FadD2 protein in Mycobacterium tuberculosis

Mycobacterium tuberculosis (Mtb) is a crucial and highly destructive intracellular pathogen responsible for causing tuberculosis (TB). The emergence and dissemination of multi-drug resistant Mtb has further aggravated the TB crisis, leading to high mortality. Mtb FadD2 is a fatty acyl-coenzyme A (CoA) synthetase that modifies the cell envelope and plays an important role in reducing Mtb susceptibility to pyrazinoic acid (POA). However, the functional mechanism of Mtb FadD2 remains poorly understood. Here, we successfully expressed, purified and obtained monomeric FadD2 by using buffer (500 mM NaCl, 20 mM Tris-HCl, pH7.4 and 5 % glycerol). Palmitate was found to be the optimal substrate for FadD2. Fatty acyl-CoA synthetase activity reached maximum at 450 μM palmitate, and the Km value was 318.2 μM for palmitate. The results of mutation experiments indicated the critical role of T370 and K551 in the enzymatic activity of FadD2. Our work provides a guideline and concept for the development of novel drugs against Mtb.

Structure of mycobacterial ergothioneine-biosynthesis C-S lyase EgtE

L-ergothioneine is widely distributed among various microbes to regulate their physiology and pathogenicity within complex environments. One of the key steps in the ergothioneine-biosynthesis pathway, the C-S bond cleavage reaction, uses the pyridoxal 5'-phosphate dependent C-S lyase to produce the final product L-ergothioneine. Here, we present the crystallographic structure of the ergothioneine-biosynthesis C-S lyase EgtE from Mycobacterium smegmatis (MsEgtE) represents the first published structure of ergothioneine-biosynthesis C-S lyases in bacteria and shows the effects of active site residues on the enzymatic reaction. The MsEgtE and the previously reported ergothioneine-biosynthesis C-S lyase Egt2 from Neurospora crassa (NcEgt2) fold similarly. However, discrepancies arise in terms of substrate recognition, as observed through sequence and structure comparison of MsEgtE and NcEgt2. The structural-based sequence alignment of the ergothioneine-biosynthesis C-S lyase from fungi and bacteria shows clear distinctions among the recognized substrate residues, but Arg348 is critical and an extremely conserved residue for substrate recognition. The α14 helix is exclusively found in the bacteria EgtE, which represent the most significant difference between bacteria EgtE and fungi Egt2, possibly resulting from the convergent evolution of bacteria and fungi.

Reduced HIV/AIDS diagnosis rates and increased AIDS mortality due to late diagnosis in Brazil during the COVID-19 pandemic

The COVID-19 pandemic has severely affected global health, leading to the suspension of numerous routine healthcare services and posing challenges in efforts to control other diseases, such as HIV/AIDS. This study aimed to assess the impact of the COVID-19 pandemic on HIV/AIDS diagnoses and mortality rates in Brazil during 2020 and 2021. The percentage change was calculated to determine whether there was an increase or decrease in HIV/AIDS diagnoses and mortality, considering the average numbers from the last 5 years. Additionally, a Joinpoint regression model and an interrupted time series analysis were applied to assess time trends before and after the onset of the pandemic. Lastly, choropleth maps were prepared. We observed a reduction of 22.4% (2020) and 9.8% (2021) in the diagnosis of HIV/AIDS in Brazil. Conversely, there was a significant increase in the percentage change of late diagnosis of AIDS deaths in 2020 (6.9%) and 2021 (13.9%), with some states showing an increase of over 87%. Decreasing time trends in the diagnosis of HIV/AIDS were identified before the pandemic in Brazil, especially in the Southeast and South regions, and then time trends stabilized after including the pandemic years. Along with the dissemination of COVID-19, there was a reduction in the diagnosis of HIV/AIDS and an increase in late diagnosis AIDS deaths, signaling a serious impact of the pandemic on HIV/AIDS control strategies in Brazil. Therefore, we highlight the need for continuous efforts to control both diseases, that is, maintaining regular health services even in crisis situations.