Drug-resistant tuberculosis, clinical virulence, and the dominance of the Beijing strain family in Russia

Context  Tuberculosis and multidrug-resistant tuberculosis is a serious public health problem in Russia. Objective  To address the extent of "Beijing strain" transmission in the prison/civil sectors and the association of drug resistance, clinical, and social factors with the Beijing genotype. Design and Setting  Cross-sectional population-based molecular epidemiological study of all civilian and penitentiary tuberculosis facilities in the Samara region, Russia. Patients  Consecutively recruited patients with bacteriologically proven tuberculosis (n = 880). Main Outcome Measure  Proportion of Beijing strains and association with drug resistance, human immunodeficiency virus infection, imprisonment, radiological, clinical, and other social factors. Results  Beijing-family strains (identified by spoligotyping and composed of 2 main types by mycobacterial interspersed repetitive unit analysis) were predominant: 586/880 (66.6%; 95% confidence interval [CI], 63.4%-69.7%) with a significantly higher prevalence in the prison population (rate ratio [RR], 1.3; 95% CI, 1.2-1.5) and those aged younger than 35 years (RR, 1.2; 95% CI, 1.0-1.3). Comparable proportions were co-infected with the human immunodeficiency virus (10%), concurrent hepatitis B and C (21.6%), drank alcohol (90%), smoked (90%), and had a similar sexual history. Drug resistance was nearly 2-fold higher in patients infected with Beijing strains compared with non-Beijing strains: multidrug resistance (RR, 2.4; 95% CI, 1.9-3.0), for isoniazid (RR, 1.8; 95% CI, 1.5-2.1), for rifampicin (RR, 2.2; 95% CI, 1.7-2.7), for streptomycin (RR, 1.9; 95% CI, 1.5-2.3), and for ethambutol (RR, 2.2; 95% CI, 1.6-3.2). Univariate analysis demonstrated that male sex (odds ratio [OR], 1.5; 95% CI, 1.1-1.9), advanced radiological abnormalities (OR, 3.3; 95% CI, 1.3-8.4), homelessness (OR, 5.6; 95% CI, 1.1-6.3), and previous imprisonment (OR, 2.0; 95% CI, 1.5-2.7) were strongly associated with Beijing-strain family disease. Multivariate analysis supported previous imprisonment to be a risk factor (OR, 2.0; 95% CI, 1.4-3.3) and night sweats to be less associated (OR 0.7; 95% CI, 0.5-1.0) with Beijing-strain disease. Conclusions  Drug resistance and previous imprisonment but not human immunodeficiency virus co-infection were significantly associated with Beijing-strain infection. There was evidence that Beijing isolates caused radiologically more advanced disease.      

Specific Interactions between the Viral Coreceptor CXCR4 and the Biguanide-Based Compound NB325 Mediate Inhibition of Human Immunodeficiency Virus Type 1 Infection

The present studies were conducted to better define the mechanism of action of polyethylene hexamethylene biguanide (PEHMB) (designated herein as NB325), which was shown in previous studies to inhibit infection by the human immunodeficiency virus type 1 (HIV-1). Fluorescence-activated flow cytometric analyses of activated human CD4⁺ T lymphocytes exposed to NB325 demonstrated concentration-dependent reductions in CXCR4 epitope recognition in the absence of altered recognition of selected CD4 or CD3 epitopes. NB325 also inhibited chemotaxis of CD4⁺ T lymphocytes induced by the CXCR4 ligand CXCL12. However, NB325 did not cause CXCR4 internalization (unlike CXCL12) and did not interfere with CXCL12 binding. Additional flow cytometric analyses using antibodies with distinct specificities for extracellular domains of CXCR4 demonstrated that NB325 specifically interfered with antibody binding to extracellular loop 2 (ECL2). This interaction was confirmed using competitive binding analyses, in which a peptide derived from CXCR4 ECL2 competitively inhibited NB325-mediated reductions in CXCR4 epitope recognition. Collectively, these results demonstrate that the biguanide-based compound NB325 inhibits HIV-1 infection by specifically interacting with the HIV-1 coreceptor CXCR4.     

Approaching COVID-19 with epidemiological genomic surveillance and the sustainability of biodiversity informatics in Africa

COVID-19 is an acute respiratory illness caused by Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2). The first case was reported in Africa on February 14, 2020 and has surged to 11 million as of July 2022, with 43% and 30% of cases in Southern and Northern Africa. Current epidemiological data demonstrate heterogeneity in transmission and patient outcomes in Africa. However, the burden of infectious diseases such as malaria creates a significant burden on public health resources that are dedicated to COVID-19 surveillance, testing, and vaccination access. Several control measures, such as the SHEF2 model, encompassed Africa's most effective preventive measure. With the help of international collaborations and partnerships, Africa's pandemic preparedness employs effective risk-management strategies to monitor patients at home and build the financial capacity and human resources needed to combat COVID-19 transmission. However, the lack of safe sanitation and inaccessible drinking water, coupled with the financial consequences of lockdowns, makes it challenging to prevent the transmission and contraction of COVID-19. The overwhelming burden on contact tracers due to an already strained healthcare system will hurt epidemiological tracing and swift counter-measures. With the rise in variants, African countries must adopt genomic surveillance and prioritize funding for biodiversity informatics.