A SARS-CoV-2 RBD vaccine fused to the chemokine MIP-3α elicits sustained murine antibody responses over 12 months and enhanced lung T-cell responses.

Background: Previous studies have demonstrated enhanced efficacy of vaccine formulations that incorporate the chemokine macrophage inflammatory protein 3α (MIP-3α) to direct vaccine antigens to immature dendritic cells. To address the reduction in vaccine efficacy associated with a mutation in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutants, we have examined the ability of receptor-binding domain vaccines incorporating MIP-3α to sustain higher concentrations of antibody when administered intramuscularly (IM) and to more effectively elicit lung T-cell responses when administered intranasally (IN). Methods: BALB/c mice aged 6-8 weeks were immunized intramuscularly or intranasally with DNA vaccine constructs consisting of the SARS-CoV-2 receptor-binding domain alone or fused to the chemokine MIP-3α. In a small-scale (n = 3/group) experiment, mice immunized IM with electroporation were followed up for serum antibody concentrations over a period of 1 year and for bronchoalveolar antibody levels at the termination of the study. Following IN immunization with unencapsulated plasmid DNA (n = 6/group), mice were evaluated at 11 weeks for serum antibody concentrations, quantities of T cells in the lungs, and IFN-γ- and TNF-α-expressing antigen-specific T cells in the lungs and spleen. Results: At 12 months postprimary vaccination, recipients of the IM vaccine incorporating MIP-3α had significantly, approximately threefold, higher serum antibody concentrations than recipients of the vaccine not incorporating MIP-3α. The area-under-the-curve analyses of the 12-month observation interval demonstrated significantly greater antibody concentrations over time in recipients of the MIP-3α vaccine formulation. At 12 months postprimary immunization, only recipients of the fusion vaccine had concentrations of serum-neutralizing activity deemed to be effective. After intranasal immunization, only recipients of the MIP-3α vaccine formulations developed T-cell responses in the lungs significantly above those of PBS controls. Low levels of serum antibody responses were obtained following IN immunization. Conclusion: Although requiring separate IM and IN immunizations for optimal immunization, incorporating MIP-3α in a SARS-CoV-2 vaccine construct demonstrated the potential of a stable and easily produced vaccine formulation to provide the extended antibody and T-cell responses that may be required for protection in the setting of emerging SARS-CoV-2 variants. Without electroporation, simple, uncoated plasmid DNA incorporating MIP-3α administered intranasally elicited lung T-cell responses.

The heme oxygenase-1 metalloporphyrin inhibitor stannsoporfin enhances the bactericidal activity of a novel regimen for multidrug-resistant tuberculosis in a murine model.

Multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb) poses significant challenges to global tuberculosis (TB) control efforts. Host-directed therapies (HDTs) offer a novel approach to TB treatment by enhancing immune-mediated clearance of Mtb. Prior preclinical studies found that the inhibition of heme oxygenase-1 (HO-1), an enzyme involved in heme metabolism, with tin-protoporphyrin IX (SnPP) significantly reduced mouse lung bacillary burden when co-administered with the first-line antitubercular regimen. Here, we evaluated the adjunctive HDT activity of a novel HO-1 inhibitor, stannsoporfin (SnMP), in combination with a novel MDR-TB regimen comprising a next-generation diarylquinoline, TBAJ-876 (S), pretomanid (Pa), and a new oxazolidinone, TBI-223 (O) (collectively, SPaO), in Mtb-infected BALB/c mice. After 4 weeks of treatment, SPaO + SnMP 5mg/kg reduced mean lung bacillary burden by an additional 0.69 log10 (P = 0.01) relative to SPaO alone. As early as 2 weeks post-treatment initiation, SnMP adjunctive therapy differentially altered the expression of pro-inflammatory cytokine genes and CD38, a marker of M1 macrophages. Next, we evaluated the sterilizing potential of SnMP adjunctive therapy in a mouse model of microbiological relapse. After 6 weeks of treatment, SPaO + SnMP 10mg/kg reduced lung bacterial burdens to 0.71 ± 0.23 log10 colony-forming units (CFUs), a 0.78 log-fold greater decrease in lung CFU compared to SpaO alone (P = 0.005). However, adjunctive SnMP did not reduce microbiological relapse rates after 5 or 6 weeks of treatment. SnMP was well tolerated and did not significantly alter gross or histological lung pathology. SnMP is a promising HDT candidate requiring further study in combination with regimens for drug-resistant TB.

HIV/Tuberculosis Coinfection in Pregnancy and the Postpartum Period.

The convergence of Human Immunodeficiency Virus (HIV) and tuberculosis (TB) represents a considerable global public health challenge. The concurrent infection of HIV and TB in pregnant women not only intensifies the transmission of HIV from mother to fetus but also engenders adverse outcomes for maternal health, pregnancy, and infant well-being, necessitating the implementation of integrated strategies to effectively address and manage both diseases. In this article, we review the pathophysiology, clinical presentation, treatment, and management of HIV/TB coinfection during pregnancy, the postpartum period, and lactation and highlight the differences compared to the general population.

Functional Whole Genome Screen of Nutrient-Starved Mycobacterium tuberculosis Identifies Genes Involved in Rifampin Tolerance.

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), poses a global health challenge and is responsible for over a million deaths each year. Current treatment is lengthy and complex, and new, abbreviated regimens are urgently needed. Mtb adapts to nutrient starvation, a condition experienced during host infection, by shifting its metabolism and becoming tolerant to the killing activity of bactericidal antibiotics. An improved understanding of the mechanisms mediating antibiotic tolerance in Mtb can serve as the basis for developing more effective therapies. We performed a forward genetic screen to identify candidate Mtb genes involved in tolerance to the two key first-line antibiotics, rifampin and isoniazid, under nutrient-rich and nutrient-starved conditions. In nutrient-rich conditions, we found 220 mutants with differential antibiotic susceptibility (218 in the rifampin screen and 2 in the isoniazid screen). Following Mtb adaptation to nutrient starvation, 82 mutants showed differential antibiotic susceptibility (80 in the rifampin screen and 2 in the isoniazid screen). Using targeted mutagenesis, we validated the rifampin-hypersusceptible phenotype under nutrient starvation in Mtb mutants lacking the following genes: ercc3, moeA1, rv0049, and rv2179c. These findings shed light on potential therapeutic targets, which could help shorten the duration and complexity of antitubercular regimens.

The heme oxygenase-1 metalloporphyrin inhibitor stannsoporfin enhances the bactericidal activity of a novel regimen for multidrug-resistant tuberculosis in a murine model.

Multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb) poses significant challenges to global tuberculosis (TB) control efforts. Host-directed therapies (HDT) offer a novel approach for TB treatment by enhancing immune-mediated clearance of Mtb. Prior preclinical studies found that inhibition of heme oxygenase-1 (HO-1), an enzyme involved in heme metabolism, with tin-protoporphyrin IX (SnPP) significantly reduced mouse lung bacillary burden when co-administered with the first-line antitubercular regimen. Here we evaluated the adjunctive HDT activity of a novel HO-1 inhibitor, stannsoporfin (SnMP), in combination with a novel MDR-TB regimen comprising a next-generation diarylquinoline, TBAJ-876 (S), pretomanid (Pa), and a new oxazolidinone, TBI-223 (O) (collectively, SPaO) in Mtb-infected BALB/c mice. After 4 weeks of treatment, SPaO + SnMP 5 mg/kg reduced mean lung bacillary burden by an additional 0.69 log10 (P=0.01) relative to SPaO alone. As early as 2 weeks post-treatment initiation, SnMP adjunctive therapy differentially altered the expression of pro-inflammatory cytokine genes, and CD38, a marker of M1 macrophages. Next, we evaluated the sterilizing potential of SnMP adjunctive therapy in a mouse model of microbiological relapse. After 6 weeks of treatment, SPaO + SnMP 10 mg/kg reduced lung bacterial burdens to 0.71 ± 0.23 log10 CFU, a 0.78 log-fold greater decrease in lung CFU compared to SpaO alone (P=0.005). However, adjunctive SnMP did not reduce microbiological relapse rates after 5 or 6 weeks of treatment. SnMP was well tolerated and did not significantly alter gross or histological lung pathology. SnMP is a promising HDT candidate requiring further study in combination with regimens for drug-resistant TB.

Combination of a MIP3α-antigen fusion therapeutic DNA vaccine with treatments of IFNα and 5-Aza-2'Deoxycytidine enhances activated effector CD8+ T cells expressing CD11c in the B16F10 melanoma model.

Previous studies in the B16F10 mouse melanoma model have demonstrated that combining a DNA vaccine comprised of regions of gp100 and tyrosinase-related protein 2 fused to Macrophage-inflammatory protein 3-alpha (MIP3α) with recombinant Interferon alpha (IFN) and 5-Aza-2'-Deoxycytidine (5Aza) treatments resulted in significantly greater anti-tumor activity and immunogenicity in the tumor microenvironment (TME). This brief report details that the combination of vaccine with treatments IFN and 5Aza results in both the upregulation of genes expressing CD11c-interacting proteins and an increase in the TME of a distinct CD11c+ CD8+ T cell population. This cell population correlates with tumor size, is primarily comprised of effector or effector memory T cells, and has a more robust response to ex vivo stimulation as compared to CD11c- CD8+ T cells as measured by surface activation markers 4-1BB (CD137) and KLRG1 (Killer cell lectin-like receptor G1) and intracellular IFNγ production. In conclusion, this combination therapy results in greater presence of highly active effector CD8+ T-cells expressing CD11c in the TME that correlate with and are likely primary contributors to treatment efficacy.

Functional whole genome screen of nutrient-starved Mycobacterium tuberculosis identifies genes involved in antibiotic tolerance.

Mycobacterium tuberculosis ( Mtb ), the causative agent of tuberculosis (TB), poses a global health challenge and is responsible for over a million deaths each year. Current treatment is lengthy and complex, and new, abbreviated regimens are urgently needed. Mtb adapts to nutrient starvation, a condition experienced during host infection, by shifting its metabolism and becoming tolerant to the killing activity of bactericidal antibiotics. An improved understanding of the mechanisms mediating antibiotic tolerance in Mtb can serve as the basis for developing more effective therapies. We performed a forward genetic screen to identify candidate Mtb genes involved in tolerance to the two key first-line antibiotics, rifampin and isoniazid, under nutrient-rich and nutrient-starved conditions. In nutrient-rich conditions, we found 220 mutants with differential antibiotic susceptibility (218 in the rifampin screen and 2 in the isoniazid screen). Following Mtb adaptation to nutrient starvation, 82 mutants showed differential antibiotic susceptibility (80 in the rifampin screen and 2 in the isoniazid screen). Using targeted mutagenesis, we validated the rifampin-hypersusceptible phenotype under nutrient starvation in Mtb mutants lacking the following genes: ercc3 , moeA1 , rv0049 , and rv2179c . These findings shed light on potential therapeutic targets, which could help shorten the duration and complexity of antitubercular regimens. Importance: Treatment of Mtb infection requires a long course of combination antibiotics, likely due to subpopulations of tolerant bacteria exhibiting decreased susceptibility to antibiotics. Identifying and characterizing the genetic pathways involved in antibiotic tolerance is expected to yield therapeutic targets for the development of novel TB treatment-shortening regimens.

Metabolic switching and cell wall remodelling of Mycobacterium tuberculosis during bone tuberculosis.

OBJECTIVES: Bone tuberculosis (TB) is the third most common types of extrapulmonary tuberculosis. It is critical to understand mycobacterial adaptive strategies within bone lesions to identify mycobacterial factors that may have role in disease pathogenesis. METHODS: Whole genome microarray was used to characterize the in-vivo transcriptome of Mycobacterium tuberculosis (M.tb) within bone TB specimens. Mycobacterial virulent proteins were identified by bioinformatic software. An in vitro osteoblast cell line model was used to study the role of these proteins in bone TB pathogenesis. RESULTS: 914 mycobacterial genes were significantly overexpressed and 1688 were repressed in bone TB specimens. Pathway analysis of differentially expressed genes demonstrated a non-replicative and hypometabolic state of M.tb, reinforcement of the mycobacterial cell wall and induction of DNA damage repair responses, suggesting possible survival strategies of M.tb within bone. Bioinformatics mining of microarray data led to identification of five virulence proteins. The genes encoding these proteins were also upregulated in the in vitro MC3T3 osteoblast cell line model of bone TB. Further, exposure of osteoblast cells to two of these virulence proteins (Rv1046c and Rv3663c) significantly inhibited osteoblast differentiation. CONCLUSION: M.tb alters its transcriptome to establish infection in bone by upregulating certain virulence genes which play a key role in disturbing bone homeostasis.

An intranasal stringent response vaccine targeting dendritic cells as a novel adjunctive therapy against tuberculosis.

Lengthy tuberculosis (TB) treatment is required to overcome the ability of a subpopulation of persistent Mycobacterium tuberculosis (Mtb) to remain in a non-replicating, antibiotic-tolerant state characterized by metabolic remodeling, including induction of the RelMtb-mediated stringent response. We developed a novel therapeutic DNA vaccine containing a fusion of the relMtb gene with the gene encoding the immature dendritic cell-targeting chemokine, MIP-3α/CCL20. To augment mucosal immune responses, intranasal delivery was also evaluated. We found that intramuscular delivery of the MIP-3α/relMtb (fusion) vaccine or intranasal delivery of the relMtb (non-fusion) vaccine potentiate isoniazid activity more than intramuscular delivery of the DNA vaccine expressing relMtb alone in a chronic TB mouse model (absolute reduction of Mtb burden: 0.63 log10 and 0.5 log10 colony-forming units, respectively; P=0.0002 and P=0.0052), inducing pronounced Mtb-protective immune signatures. The combined approach involving intranasal delivery of the DNA MIP-3α/relMtb fusion vaccine demonstrated the greatest mycobactericidal activity together with isoniazid when compared to each approach alone (absolute reduction of Mtb burden: 1.13 log10, when compared to the intramuscular vaccine targeting relMtb alone; P<0.0001), as well as robust systemic and local Th1 and Th17 responses. This DNA vaccination strategy may be a promising adjunctive approach combined with standard therapy to shorten curative TB treatment, and also serves as proof of concept for treating other chronic bacterial infections.

HDL cholesterol levels and susceptibility to COVID-19.

BACKGROUND: Host cell-membrane cholesterol, an important player in viral infections, is in constant interaction with serum high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C). Low serum lipid levels during hospital admission are associated with COVID-19 severity. However, the effect of antecedent serum lipid levels on SARS-CoV-2 infection risk has not been explored. METHODS: From our retrospective cohort from the Arkansas Clinical Data-Repository, we used log-binomial regression to assess the risk of SARS-CoV-2 infection among the trajectories of lipid levels during the 2 years antecedent to COVID-19 testing, identified using group-based-trajectory modelling. We used mixed-effects linear regression to assess the serum lipid level trends followed up to the time of, and 2-months following COVID-19 testing. FINDINGS: Among the 11001 individuals with a median age of 59 years (IQR 46-70), 1340 (12.2%) tested positive for COVID-19. The highest trajectory for antecedent serum HDL-C was associated with the lowest SARS-CoV-2 infection risk (RR 0.63, 95%CI 0.46-0.86). Antecedent serum LDL-C, total cholesterol (TC), and triglycerides (TG) were not independently associated with SARS-CoV-2 infection risk. In COVID-19 patients, serum HDL-C (-7.7, 95%CI -9.8 to -5.5 mg/dL), and LDL-C (-6.29, 95%CI -12.2 to -0.37 mg/dL), but not TG levels, decreased transiently at the time of testing. INTERPRETATION: Higher antecedent serum HDL-C, but not LDL-C, TC, or TG, levels were associated with a lower SARS-CoV-2 infection risk. Serum HDL-C, and LDL-C levels declined transiently at the time of infection. Further studies are needed to determine the potential role of lipid-modulating therapies in the prevention and management of COVID-19. FUNDING: Research reported in this publication was supported by the National Center for Advancing Translational Sciences of the National Institutes of Health under Award Number UL1 TR003107.

Association of Lipid Levels With COVID-19 Infection, Disease Severity and Mortality: A Systematic Review and Meta-Analysis.

Background: Coronavirus disease 2019 (COVID-19) ranges from asymptomatic infection to severe illness. Cholesterol in the host cell plasma membrane plays an important role in the SARS-CoV-2 virus entry into cells. Serum lipids, especially low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), are in constant interaction with the lipid rafts in the host cell membranes and can modify the interaction of virus with host cells and the resultant disease severity. Recent studies on serum lipid levels and COVID-19 disease severity lack consistency. Objectives: Our systematic review and meta-analysis compared the serum levels of total cholesterol (TC), LDL-C, HDL-C, and triglycerides (TG) between (1) COVID-19 patients vs. healthy controls; (2) severe vs. non-severe COVID-19 disease; (3) deceased vs. surviving COVID-19 patients. Methods: PRISMA guidelines were followed. We included peer-reviewed articles on observational (case-control and cohort) studies from PubMed and Embase published from the database inception until September 1, 2021. We used random-effects meta-analysis for pooled mean-differences (pMD) in lipid levels (mg/dL) for the above groups. Results: Among 441 articles identified, 29 articles (26 retrospective and 3 prospective cohorts), with an aggregate of 256,721 participants, were included. COVID-19 patients had lower TC (pMD-14.9, 95%CI-21.6 to -8.3) and HDL-C (pMD-6.9, 95%CI -10.2 to -3.7) levels (mg/dL). Severe COVID-19 patients had lower TC (pMD-10.4, 95%CI -18.7 to -2.2), LDL-C (pMD-4.4, 95%CI -8.4 to -0.42), and HDL-C (pMD-4.4, 95%CI -6.9 to -1.8) at admission compared to patients with non-severe disease. Deceased patients had lower TC (pMD-14.9, 95%CI -21.6 to -8.3), LDL-C (pMD-10.6, 95%CI -16.5 to -4.6) and HDL-C (pMD-2.5, 95%CI -3.9 to -1.0) at admission. TG levels did not differ based on COVID-19 severity or mortality. No publication bias was noted. Conclusion: We demonstrated lower lipid levels in patients with COVID-19 infection and an association with disease severity and mortality. Their potential role in COVID-19 pathogenesis and their utility as prognostic factors require further investigation.

Progression and Resolution of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection in Golden Syrian Hamsters.

To catalyze severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) research, including development of novel interventive and preventive strategies, the progression of disease was characterized in a robust coronavirus disease 2019 (COVID-19) animal model. In this model, male and female golden Syrian hamsters were inoculated intranasally with SARS-CoV-2 USA-WA1/2020. Groups of inoculated and mock-inoculated uninfected control animals were euthanized at 2, 4, 7, 14, and 28 days after inoculation to track multiple clinical, pathology, virology, and immunology outcomes. SARS-CoV-2-inoculated animals consistently lost body weight during the first week of infection, had higher lung weights at terminal time points, and developed lung consolidation per histopathology and quantitative image analysis measurements. High levels of infectious virus and viral RNA were reliably present in the respiratory tract at days 2 and 4 after inoculation, corresponding with widespread necrosis and inflammation. At day 7, when the presence of infectious virus was rare, interstitial and alveolar macrophage infiltrates and marked reparative epithelial responses (type II hyperplasia) dominated in the lung. These lesions resolved over time, with only residual epithelial repair evident by day 28 after inoculation. The use of quantitative approaches to measure cellular and morphologic alterations in the lung provides valuable outcome measures for developing therapeutic and preventive interventions for COVID-19 using the hamster COVID-19 model.

IFNα and 5-Aza-2'-deoxycytidine combined with a dendritic-cell targeting DNA vaccine alter tumor immune cell infiltration in the B16F10 melanoma model.

Introduction: DNA vaccines containing a fusion of the gene encoding chemokine MIP-3α (CCL20), the ligand for CCR6 on immature dendritic cells (DCs), to melanoma-associated antigen genes have enhanced anti-tumor immunity and efficacy compared to those lacking the chemokine gene. Previous work has shown that type-I interferon (IFNα or IFN) and 5-Aza-2'-deoxycytidine (5Aza) significantly enhance the therapeutic benefit of DNA vaccines as measured by reduced tumor burden and improved mouse survival. Methods: Here, we explored mouse intratumoral immune correlates underlying the therapeutic benefit of this combination regimen (vaccine, IFN, and 5Aza) as compared to vaccine alone and IFN and 5Aza without vaccine, focusing on chemokine mRNA expression by qRT-PCR and inflammatory cellular infiltration into the tumor microenvironment (TME) by flow cytometry and immunohistochemistry (IHC). Results: The combination group significantly upregulated intratumoral mRNA expression of key immune infiltration chemokines XCL1 and CXCL10. Flow cytometric analyses of tumor suspensions exhibited greater tumor infiltration of CD8+ DCs, CCR7+ DCs, and NK cells in the combination group, as well as reduced levels of myeloid-derived suppressor cells (MDSCs) in vaccinated groups. The mice receiving combination therapy also had greater proportions of effector/memory T-cells (Tem), in addition to showing an enhanced infiltration of Tem and central memory CD8+ T-cells, (Tcm). Tem and Tcm populations both correlated with smaller tumor size. Immunohistochemical analysis of tumors confirmed that CD8+ cells were more abundant overall and especially in the tumor parenchyma with combination therapy. Discussion: Efficient targeting of antigen to immature DCs with a chemokine-fusion vaccine offers a potential alternative approach to classic and dendritic cell-based vaccines. Combining this approach with IFNα and 5Aza treatments significantly improved vaccine efficacy. This treatment creates an environment of increased inflammatory chemokines that facilitates the trafficking of CD8+ DCs, NK cells, and CD8+ T-cells, especially memory cells, while reducing the number of MDSCs. Importantly, in the combination group, CD8+ cells were more able to penetrate the tumor mass in addition to being more numerous. Further analysis of the pathways engaged by our combination therapy is expected to provide additional insights into melanoma pathogenesis and facilitate the development of novel treatment strategies.

Targeting the Mycobacterium tuberculosis Stringent Response as a Strategy for Shortening Tuberculosis Treatment.

The stringent response is well conserved across bacterial species and is a key pathway involved both in bacterial survival and virulence and in the induction of antibiotic tolerance in Mycobacteria. It is mediated by the alarmone (p)ppGpp and the regulatory molecule inorganic polyphosphate in response to stress conditions such as nutrient starvation. Efforts to pharmacologically target various components of the stringent response have shown promise in modulating mycobacterial virulence and antibiotic tolerance. In this review, we summarize the current understanding of the stringent response and its role in virulence and tolerance in Mycobacteria, including evidence that targeting this pathway could have therapeutic benefit.

The Global Health Security Index is not predictive of vaccine rollout responses among OECD countries.

OBJECTIVE: This study sought to evaluate the utility of the Global Health Security (GHS) index in predicting the launch of COVID-19 vaccine rollout by Organization for Economic Cooperation and Development (OECD) member countries. METHODS: Country-level data on the preparedness to respond to infectious disease threats through vaccination rollout were collected using the GHS index. OECD member countries were rank-ordered based on the percentage of their populations fully vaccinated against COVID-19. Rank-ordering was conducted from the lowest to the highest, with each country assigned a score ranging from 1 to 33. Spearman's rank correlation between the GHS index and the percentage of the population that is fully vaccinated was also performed. RESULTS: Israel, ranked 34th in the world on the GHS index for pandemic preparedness, had the highest percentage of the population that was fully vaccinated against COVID-19 within 2 months of the global vaccine rollout. The Spearman rank correlation coefficient between GHS index and the percentage of population fully vaccinated was -0.1378, with a p-value of 0.43. CONCLUSION: The findings suggest an absence of correlation between the GHS index rating and the COVID-19 vaccine rollout of OECD countries, indicating that the preparedness of OECD countries for infectious disease threats may not be accurately reflected by the GHS index.

Statins use and COVID-19 outcomes in hospitalized patients.

BACKGROUND: There is an urgent need for novel therapeutic strategies for reversing COVID-19-related lung inflammation. Recent evidence has demonstrated that the cholesterol-lowering agents, statins, are associated with reduced mortality in patients with various respiratory infections. We sought to investigate the relationship between statin use and COVID-19 disease severity in hospitalized patients. METHODS: A retrospective analysis of COVID-19 patients admitted to the Johns Hopkins Medical Institutions between March 1, 2020 and June 30, 2020 was performed. The outcomes of interest were mortality and severe COVID-19 infection, as defined by prolonged hospital stay (≥ 7 days) and/ or invasive mechanical ventilation. Logistic regression, Cox proportional hazards regression and propensity score matching were used to obtain both univariable and multivariable associations between covariates and outcomes in addition to the average treatment effect of statin use. RESULTS: Of the 4,447 patients who met our inclusion criteria, 594 (13.4%) patients were exposed to statins on admission, of which 340 (57.2%) were male. The mean age was higher in statin users compared to non-users [64.9 ± 13.4 vs. 45.5 ± 16.6 years, p <0.001]. The average treatment effect of statin use on COVID-19-related mortality was RR = 1.00 (95% CI: 0.99-1.01, p = 0.928), while its effect on severe COVID-19 infection was RR = 1.18 (95% CI: 1.11-1.27, p <0.001). CONCLUSION: Statin use was not associated with altered mortality, but with an 18% increased risk of severe COVID-19 infection.

Genetic Determinants of Intrinsic Antibiotic Tolerance in Mycobacterium avium.

The Mycobacterium avium complex (MAC) is one of the most prevalent causes of nontuberculous mycobacteria pulmonary infection in the United States, and yet it remains understudied. Current MAC treatment requires more than a year of intermittent to daily combination antibiotic therapy, depending on disease severity. In order to shorten and simplify curative regimens, it is important to identify the innate bacterial factors contributing to reduced antibiotic susceptibility, namely, antibiotic tolerance genes. In this study, we performed a genome-wide transposon screen to elucidate M. avium genes that play a role in the bacterium's tolerance to first- and second-line antibiotics. We identified a total of 193 unique M. avium mutants with significantly altered susceptibility to at least one of the four clinically used antibiotics we tested, including two mutants (in DFS55_00905 and DFS55_12730) with panhypersusceptibility. The products of the antibiotic tolerance genes we have identified may represent novel targets for future drug development studies aimed at shortening the duration of therapy for MAC infections. IMPORTANCE The prolonged treatment required to eradicate Mycobacterium avium complex (MAC) infection is likely due to the presence of subpopulations of antibiotic-tolerant bacteria with reduced susceptibility to currently available drugs. However, little is known about the genes and pathways responsible for antibiotic tolerance in MAC. In this study, we performed a forward genetic screen to identify M. avium antibiotic tolerance genes, whose products may represent attractive targets for the development of novel adjunctive drugs capable of shortening the curative treatment for MAC infections.

Higher Serum Cholesterol Levels Are Associated With Reduced Systemic Inflammation and Mortality During Tuberculosis Treatment Independent of Body Mass Index.

Background: Lipids play a central role in the pathogenesis of tuberculosis (TB). The effect of serum lipid levels on TB treatment (ATT) outcomes and their association with serum inflammatory markers have not yet been characterized. Methods: Our retrospective cohort study on drug-susceptible TB patients, at the National Taiwan University Hospital, assessed the association of baseline serum lipid levels such as low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC) and triglycerides (TG) with all-cause and infection-related mortality during first 9 months of ATT and baseline inflammatory markers namely C-reactive protein (CRP), total leukocyte count (WBC), and neutrophil-lymphocyte ratio (NL ratio). Results: Among 514 patients, 129 (26.6%) died due to any-cause and 72 (14.0%) died of infection. Multivariable Cox-regression showed a lower adjusted hazard ratio (aHR) of all-cause mortality in the 3rd tertiles of HDL (aHR 0.17, 95% CI 0.07-0.44) and TC (aHR 0.30, 95% CI 0.14-0.65), and lower infection-related mortality in the 3rd tertile of HDL (aHR 0.30, 95% CI 0.14-0.65) and TC (aHR 0.30, 95% CI 0.14-0.65) compared to the 1st tertile. The 3rd tertiles of LDL and TG showed no association in multivariable analysis. Similarly, 3rd tertiles of HDL and TC had lower levels of baseline inflammatory markers such as CRP, WBC, and NL ratio using linear regression analysis. Body mass index (BMI) did not show evidence of confounding or effect modification. Conclusions: Higher baseline serum cholesterol levels were associated with lower hazards of all-cause and infection-related mortality and lower levels of inflammatory markers in TB patients. BMI did not modify or confound this association.

Sex Differences in Lung Imaging and SARS-CoV-2 Antibody Responses in a COVID-19 Golden Syrian Hamster Model.

In the coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), more severe outcomes are reported in males than in females, including hospitalizations and deaths. Animal models can provide an opportunity to mechanistically interrogate causes of sex differences in the pathogenesis of SARS-CoV-2. Adult male and female golden Syrian hamsters (8 to 10 weeks of age) were inoculated intranasally with 105 50% tissue culture infective dose (TCID50) of SARS-CoV-2/USA-WA1/2020 and euthanized at several time points during the acute (i.e., virus actively replicating) and recovery (i.e., after the infectious virus has been cleared) phases of infection. There was no mortality, but infected male hamsters experienced greater morbidity, losing a greater percentage of body mass, developed more extensive pneumonia as noted on chest computed tomography, and recovered more slowly than females. Treatment of male hamsters with estradiol did not alter pulmonary damage. Virus titers in respiratory tissues, including nasal turbinates, trachea, and lungs, and pulmonary cytokine concentrations, including interferon-ß (IFN-ß) and tumor necrosis factor-α (TNF-α), were comparable between the sexes. However, during the recovery phase of infection, females mounted 2-fold greater IgM, IgG, and IgA responses against the receptor-binding domain of the spike protein (S-RBD) in both plasma and respiratory tissues. Female hamsters also had significantly greater IgG antibodies against whole-inactivated SARS-CoV-2 and mutant S-RBDs as well as virus-neutralizing antibodies in plasma. The development of an animal model to study COVID-19 sex differences will allow for a greater mechanistic understanding of the SARS-CoV-2-associated sex differences seen in the human population. IMPORTANCE Men experience more severe outcomes from coronavirus disease 2019 (COVID-19) than women. Golden Syrian hamsters were used to explore sex differences in the pathogenesis of a human isolate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). After inoculation, male hamsters experienced greater sickness, developed more severe lung pathology, and recovered more slowly than females. Sex differences in disease could not be reversed by estradiol treatment in males and were not explained by either virus replication kinetics or the concentrations of inflammatory cytokines in the lungs. During the recovery period, antiviral antibody responses in the respiratory tract and plasma, including to newly emerging SARS-CoV-2 variants, were greater in female than in male hamsters. Greater lung pathology during the acute phase combined with lower antiviral antibody responses during the recovery phase of infection in males than in females illustrate the utility of golden Syrian hamsters as a model to explore sex differences in the pathogenesis of SARS-CoV-2 and vaccine-induced immunity and protection.