Production and Evaluation of Ag85B:HspX:hFcγ1 Immunogenicity as an Fc Fusion Recombinant Multi-Stage Vaccine Candidate Against Mycobacterium tuberculosis.

An urgent need is to introduce an effective vaccine against Mycobacterium tuberculosis (M.tb) infection. In the present study, a multi-stage M.tb immunodominant Fcγ1 fusion protein (Ag85B:HspX:hFcγ1) was designed and produced, and the immunogenicity of purified protein was evaluated. This recombinant fusion protein was produced in the Pichia pastoris expression system. The HiTrap-rPA column affinity chromatography purified and confirmed the fusion protein using ELISA and Western blotting methods. The co-localisation assay was used to confirm its proper folding and function. IFN-γ, IL-12, IL-4, and TGF-ß expression in C57BL/6 mice then evaluated the immunogenicity of the construct in the presence and absence of BCG. After expression optimisation, medium-scale production and the Western blotting test confirmed suitable production of Ag85B:HspX:hFcγ1. The co-localisation results on antigen-presenting cells (APCs) showed that Ag85B:HspX:hFcγ1 properly folded and bound to hFcγRI. This strong co-localisation with its receptor can confirm inducing proper Th1 responses. The in vivo immunisation assay showed no difference in the expression of IL-4 but a substantial increase in the expression of IFN-γ and IL-12 (P ≤ 0.02) and a moderate increase in TGF-ß (P = 0.05). In vivo immunisation assay revealed that Th1-inducing pathways have been stimulated, as IFN-γ and IL-12 strongly, and TGF-ß expression moderately increased in Ag85B:HspX:hFcγ1 group and Ag85B:HspX:hFcγ1+BCG. Furthermore, the production of IFN-γ from splenocytes in the Ag85B:HspX:hFcγ1 group was enormously higher than in other treatments. Therefore, this Fc fusion protein can make a selective multi-stage delivery system for inducing appropriate Th1 responses and is used as a subunit vaccine alone or in combination with others.

Global distribution of heterogeneous vancomycin-intermediate Staphylococcus aureus strains (1997-2021): a systematic review and meta-analysis.

BACKGROUND: Heterogeneous vancomycin-intermediate Staphylococcus aureus is considered one of the main causes in treatment failure of vancomycin, which leads to poor clinical outcomes. Herein, we comprehensively evaluated characteristics such as global prevalence, trend, and genetic backgrounds of these strains. METHODS: In this study, we conducted a meta-analysis based on PRISMA checklist 2020. In the beginning, global databases were searched to achieve the studies related to the prevalence of hVISA in clinical isolates of methicillin-resistant Staphylococcus aureus. After retrieving the eligible English studies, the prevalence of hVISA isolates and their trend changes were assessed using event rate with 95% confidence intervals. RESULTS: In the present study, the prevalence of 114 801 MRSA isolates (of 124 studies) was 64%. According to our results, although the frequency of infection with hVISA is increasing in recent years, there is not a significant difference between Asian countries and Europe/America (6.1% vs. 6.8%). In addition, infection with hVISA bacteria was higher in bacteraemic patients than other infections (9.4% vs. 5.5%), which increases hospitalization, treatment costs, and mortality in these patients. Isolates harbouring SCCmec types II and III are most common genotypes in hVISA strains. CONCLUSIONS: The prevalence of hVISA is increasing, which will reduce the effectiveness of vancomycin treatment in the coming years. The presence of hVISA stains in blood samples was higher than the other samples, which is threatening for bacteraemic patients. The results of the current study indicate a universal program to identify and control the spread of such strains in nosocomial infections.

First global report about the prevalence of multi-drug resistant Haemophilus influenzae: a systematic review and meta-analysis.

BACKGROUND: In recent decades, the prevalence of antibiotic resistance is increasing in Haemophilus influenzae (Haemophilus influenzae), which poses important challenges to global health. This research offers a comprehensive meta-analysis of the global epidemiology of multi-drug resistant (MDR) H. influenzae. METHODS: In this study, we conducted a meta-analysis based on PRISMA checklist. Electronic databases including PubMed, ISI Web of Science, Scopus, EMBASE, and Google Scholar were reviewed using keywords related to H. influenzae and antibiotic resistance. Eligible studies were selected based on stringent inclusion and exclusion criteria. Then, data from these studies were analyzed using the Comprehensive Meta-Analysis (CMA) software. RESULTS: Of 375 retrieved articles, 16 met the inclusion criteria. These studies were conducted from 2003 to 2023 and analyzed data from 19,787 clinical isolates of H. influenzae. The results showed different levels of resistance of H. influenzae to different antibiotics: ampicillin (36%), azithromycin (15.3%), ceftriaxone (1.4%), etc. The global prevalence for beta-lactamases producing H. influenzae and MDR H. influenzae was measured 34.9% and 23.1%, respectively. The prevalence rate of MDR H. influenzae was higher in Asian countries (24.6%) compared to Western regions (15.7%). MDR H. influenzae had the highest prevalence in meningitis cases (46.9%) and the lowest prevalence in acute otitis media (0.5%). CONCLUSIONS: The prevalence of MDR H. influenzae has been increasing worldwide, especially in Asian regions. This highlights the urgent need for monitoring and implementation of effective antibiotic stewardship programs globally.

Biofilm Formation Status in ESBL-Producing Bacteria Recovered from Clinical Specimens of Patients: A Systematic Review and Meta-Analysis.

BACKGROUND: Recently, the emergence and spread of extended-spectrum beta-lactamase (ESBL) bacteria have become a global health concern. In addition, the ability to form biofilm due to less impermeability to antibiotics and the horizontal transformation (conjugation) of genes involved in antibiotic resistance have exacerbated the concerns. With a comprehensive meta-analysis, this study evaluated the potential relationship between ESBL and biofilm formation. METHODS: A literature search was performed using global databases, such as PubMed and Scopus, up to November 2021. We retrieved all relevant documents and selected eligible articles based on inclusion criteria. Finally, the potential association between the biofilm formation capacity and resistance of ESBL-producing bacteria was measured with an odds ratio and a 95% confidence interval. RESULTS: In the present study, 17 articles, including 2,069 Gram-negative isolates, were considered as eligible. The prevalence of biofilm formation in all clinical isolates of ESBL and non-ESBL pathogens was 72.4% (95% CI: 60.7-81.6) and 40.5% (95% CI: 30.2-51.8), respectively. Our results showed a positive relationship between the ability for biofilm formation and conferring antibiotic resistance in ESBL-producing bacteria (OR: 3.35; 95% CI: 1.67-6.74; p-value: 0.001). CONCLUSION: In general, we showed the rate of biofilm formation to be significantly higher in ESBLproducing strains. Given the current results, the updated therapeutic guidelines should consider the role of biofilm production for optimal therapy, treatment course, and clinical outcomes rather than the recommendation of antimicrobial agents by focusing on the results of the antibiotic susceptibility test.

Antimicrobial peptides: natural or synthetic defense peptides against HBV and HCV infections.

According to the literature, treatment of HCV and HBV infections faces challenges due to problems such as the emergence of drug-resistant mutants, the high cost of treatment, and the side effects of current antiviral therapy. Antimicrobial peptides (AMPs), a group of small peptides, are a part of the immune system and are considered as an alternative treatment for microbial infections. These peptides are water-soluble with amphiphilic (hydrophilic and hydrophobic surfaces) characteristics. AMPs are produced by a wide range of organisms including both prokaryotic and eukaryotic cells. The antiviral mechanisms of AMPs include inhibiting virus entry, inhibiting intracellular virus replication, inhibiting intracellular viral packaging, and inducing immune responses. In addition, AMPs are a new generation of antiviral biomolecules that have very low toxicity for human host cells, particularly liver cell lines. AMPs can be considered as one of the most important strategies for developing new adjuvant drugs in the treatment of HBV and HCV infections. In the present study, several groups of AMPs (with a net positive charge) such as Human cathelicidin, Claudin-1, Defensins, Hepcidin, Lactoferrin, Casein, Plectasin, Micrococcin P1, Scorpion venom, and Synthetic peptides were reviewed with antiviral properties against HBV and HCV.

Statistical proof of Helicobacter pylori eradication in preventing metachronous gastric cancer after endoscopic resection in an East Asian population.

We conducted a comprehensive literature review and meta-analysis study on the efficacy of Helicobacter pylori (H. pylori) eradication in preventing metachronous gastric cancer after endoscopic resection among an East Asian population. Our results showed that the eradication of this pathogen significantly reduced the risk of susceptibility to metachronous gastric cancer in these patients. However, based on the available evidence, several factors such as increasing age, severe atrophy in the corpus and antrum, and intestinal metaplasia all may increase the risk of metachronous gastric cancer in H. pylori eradicated patients.

Global distribution of ACE1 (rs4646994) and ACE2 (rs2285666) polymorphisms associated with COVID-19: A systematic review and meta-analysis.

BACKGROUND: Recent studies emphasize the significant impact of the renin-angiotensin aldosterone system (RAAS) as a risk factor associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, according to the literature, the effect of rs4646994 and rs2285666 polymorphisms on susceptibility and progression to severe clinical outcomes is still controversial. Our aim was to investigate the effect of polymorphisms such as rs4646994 and rs2285666 on susceptibility to coronavirus disease-2019 (COVID-19). METHODS: We conducted a comprehensive literature search using databases such as ISI Web of Science, PubMed, Scopus, and Google Scholar to retrieve studies on the effect of two polymorphisms (rs4646994 and rs2285666) of the angiotensin-converting enzyme (ACE) gene on COVID-19. Finally, the effect of each polymorphism on SARS-CoV-2 infection was measured based on the odds ratio with 95% confidence intervals. RESULTS: Analysis of the rs4646994 polymorphism showed that the frequency of the D allele in patients infected with COVID-19 was higher than that the I allele. Moreover, the authors found that the DD genotype increased the risk of severe disease by 1.7-fold in Asian population, whereas, this was not the case in the Western population. However, the rs4646994 II genotype plays a protective role against COVID-19 in Western countries. In the case of the rs2285666 polymorphism based on patient ethnicity, the C allele had the highest frequency. Interestingly, in people harboring the GG and TT genotypes, the risk of progression to severe disease significantly increased, while people with genotypes such as GA, AA and CC seem to be more resistant to severe Covid-19. CONCLUSIONS: Based on geographical region, the rs4646994 DD genotype may be considered as a predictive biomarker to identify the susceptibility of human to SARS-CoV-2 infection and severe COVID-19 outcomes. We also concluded that individuals with GG and TT genotypes are significantly more susceptible to severe outcomes of disease, while conversely, individuals with GA, AA, and CC genotypes are less susceptible to severe COVID-19.

Prevalence of Primary Multidrug-resistant Helicobacter pylori in Children: A Systematic Review and Meta-analysis.

BACKGROUND: The emergence and global spread of multidrug-resistant Helicobacter pylori (MDR H. pylori) is a major health problem in children, which can increase the risk of serious complications such as gastric cancer. The aim of this study was to determine the prevalence of primary MDR H. pylori in children via a comprehensive systematic literature review and meta-analysis. METHODS: All potential studies were collected from international databases like: ISI Web of Science, Embase, PubMed, Google Scholar, and Scopus from 2011-July 24, 2022. Ultimately, primary MDR H. pylori in children was measured as an event rate with corresponding 95% confidence intervals. RESULTS: A total of 19 studies met the inclusion criteria. The overall prevalence of primary MDR H. pylori in children was measured at 6.0% (95% CI: 3.1-11.6); There was a significant difference in primary MDR H. pylori resistance rates between Asian populations and Western countries. CONCLUSIONS: The global spread of MDR H. pylori strains could significantly limit the options of anti-H. pylori treatment regimens. The frequency of primary MDR H. pylori infection differs between various geographical regions. Thus, drug susceptibility testing and the eradication of H. pylori infection can effectively reduce and control the spread of H. pylori antibiotic resistance throughout the world.

Selective APC-targeting of a novel Fc-fusion multi-immunodominant recombinant protein (tTax-tEnv:mFcγ2a) for HTLV-1 vaccine development.

AIMS: HTLV-1 causes two life-threatening diseases: adult T-cell leukaemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis. Due to the lack of proper treatment, an effective HTLV-1 vaccine is urgently needed. MAIN METHODS: DNA sequences of 11-19 and 178-186 amino acids of HTLV-1-Tax and SP2 and P21 were fused to the mouse-Fcγ2a, or His-tag called tTax-tEnv:mFcγ2a and tTax-tEnv:His, respectively. These constructs were produced in Pichia pastoris, and their immunogenicity and protective properties were assessed in a mouse challenging model with an HTLV-1-MT2 cell line. KEY FINDINGS: The immunogenicity assessments showed significant increase in IFN-γ production in animals receiving tTax-tEnv:mFcγ2a (1537.2 ± 292.83 pg/mL) compared to tTax-tEnv:His (120.28 ± 23.9, p = 0.02). IL-12 production also increased in group receiving tTax-tEnv:mFcγ2a than tTax-tEnv:His group, (23 ± 2.6 vs 1.5 ± 0.6, p = 0.01), respectively. The IFN-γ and IL-12 levels in the Fc-immunised group were negatively correlated with PVL (R = -0.82, p < 0.04) and (R = -0.87, p = 0.05), respectively. While, IL-4 was increased by tTax-tEnv:His (21.16 ± 1.76 pg/mL) compared to tTax-tEnv:mFcγ2a (13.7 ± 1.49, p = 0.019) with a negative significant correlation to PVL (R = -0.95, p = 0.001). SIGNIFICANCE: The mouse challenging assay with tTax-tEnv:mFcγ2a showed 50 % complete protection and a 50 % low level of HTLV-1-PVL compared to the positive control receiving HTLV-1-MT2 (p = 0.001). Challenging experiments for the His-tag protein showed the same outcome (p = 0.002) but by different mechanisms. The Fc-fusion construct induced more robust Th1, and His-tag protein shifted more to Th2 immune responses. Therefore, inducing both T helper responses, but a Th1/Th2 balance in favour of Th1 might be necessary for appropriate protection against HTLV-1 infection, spreading via cell-to-cell contact manner.

A Comprehensive Survey of the Relationship between Helicobacter pylori Infection and Atherosclerosis in the Iranian Population: A Systematic Review and Meta-analysis.

BACKGROUND: Helicobacter pylori is a gram-negative, spiral-shaped, and microaerophilic bacterium that inhabits the human gastric mucosa and is considered to be the most important etiologic agent for gastrointestinal disorders. Recently, however, there is ample evidence to suggest an association between H. pylori infection and extragastric complications, particularly atherosclerosis. The aim of this study was to evaluate the rate of H. pylori infection and the risk of atherosclerosis in an Iranian population. METHODS: We conducted a comprehensive electronic search on PubMed, Scopus, Google scholar, IranMedex, SID, ISC, and Magiran to find the main published documents related to the relationship between H. pylori and atherosclerosis in Iran. A summary odds ratio with 95% confidence interval was used to investigate the potential association between H. pylori and atherosclerosis. In addition, the heterogeneity between studies was assessed by the I2 index and the Cochrane Q-test. Publication bias was determined using a funnel plot. RESULTS: A total of 12 studies met our inclusion criteria and were included in the present study. The results showed that there is a significant positive relationship between infection with this bacterium and the two-fold risk of developing atherosclerosis in the Iranian population (OR: 1.44; 95% CI: 1.07-1.95). However, the heterogeneity was significant and we observed a slight publication bias. CONCLUSION: We confirmed a positive relationship between H. pylori infection and atherosclerosis in the Iranian population, which is similar to other reports from Western countries. Most likely, H. pylori infection can increase the risk of developing atherosclerosis.