EVOLUTION: Of Mice . . .

Gut microbial induction of host immune maturation exemplifies host-microbe mutualism. We colonized germ-free (GF) mice with mouse microbiota (MMb) or human microbiota (HMb) to determine whether small intestinal immune maturation depends on a coevolved host-specific microbiota. Gut bacterial numbers and phylum abundance were similar in MMb and HMb mice, but bacterial species differed, especially the Firmicutes. HMb mouse intestines had low levels of CD4(+) and CD8(+) T cells, few proliferating T cells, few dendritic cells, and low antimicrobial peptide expression--all characteristics of GF mice. Rat microbiota also failed to fully expand intestinal T cell numbers in mice. Colonizing GF or HMb mice with mouse-segmented filamentous bacteria (SFB) partially restored T cell numbers, suggesting that SFB and other MMb organisms are required for full immune maturation in mice. Importantly, MMb conferred better protection against Salmonella infection than HMb. A host-specific microbiota appears to be critical for a healthy immune system.

Gut Immune Maturation Depends Upon Colonization with Host-Specific Microbiota

Qualified presumption of safety (QPS) was developed to provide a generic safety evaluation for biological agents to support EFSA's Scientific Panels. The taxonomic identity, body of knowledge, safety concerns and antimicrobial resistance are assessed. Safety concerns identified for a taxonomic unit (TU) are where possible to be confirmed at strain or product level, reflected by 'qualifications'. No new information was found that would change the previously recommended QPS TUs and their qualifications. The list of microorganisms notified to EFSA was updated with 54 biological agents, received between April and September 2019; 23 already had QPS status, 14 were excluded from the QPS exercise (7 filamentous fungi, 6 Escherichia coli, Sphingomonas paucimobilis which was already evaluated). Seventeen, corresponding to 16 TUs, were evaluated for possible QPS status, fourteen of these for the first time, and Protaminobacter rubrum, evaluated previously, was excluded because it is not a valid species. Eight TUs are recommended for QPS status. Lactobacillus parafarraginis and Zygosaccharomyces rouxii are recommended to be included in the QPS list. Parageobacillus thermoglucosidasius and Paenibacillus illinoisensis can be recommended for the QPS list with the qualification 'for production purposes only' and absence of toxigenic potential. Bacillus velezensis can be recommended for the QPS list with the qualification 'absence of toxigenic potential and the absence of aminoglycoside production ability'. Cupriavidus necator, Aurantiochytrium limacinum and Tetraselmis chuii can be recommended for the QPS list with the qualification 'production purposes only'. Pantoea ananatis is not recommended for the QPS list due to lack of body of knowledge in relation to its pathogenicity potential for plants. Corynebacterium stationis, Hamamotoa singularis, Rhodococcus aetherivorans and Rhodococcus ruber cannot be recommended for the QPS list due to lack of body of knowledge. Kodamaea ohmeri cannot be recommended for the QPS list due to safety concerns.

https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2020.5965

Update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA 13: suitability of taxonomic units notified to EFSA until September 2020.

Iconographies supplémentaires de l'article : New insights into the antiviral effects of chloroquine

Human breast milk is considered the optimum feeding regime for newborn infants due to its ability to provide complete nutrition and many bioactive health factors. Breast feeding is associated with improved infant health and immune development, less incidences of gastrointestinal disease and lower mortality rates than formula fed infants. As well as providing fundamental nutrients to the growing infant, breast milk is a source of commensal bacteria which further enhance infant health by preventing pathogen adhesion and promoting gut colonisation of beneficial microbes. While breast milk was initially considered a sterile fluid and microbes isolated were considered contaminants, it is now widely accepted that breast milk is home to its own unique microbiome. The origins of bacteria in breast milk have been subject to much debate, however, the possibility of an entero-mammary pathway allowing for transfer of microbes from maternal gut to the mammary gland is one potential pathway. Human milk derived strains can be regarded as potential probiotics; therefore, many studies have focused on isolating strains from milk for subsequent use in infant health and nutrition markets. This review aims to discuss mammary gland development in preparation for lactation as well as explore the microbial composition and origins of the human milk microbiota with a focus on probiotic development.

Breast Milk, a Source of Beneficial Microbes and Associated Benefits for Infant Health.

ISSN To date, tuberculosis (TB) infection, is the most threatening infectious disease in all humans around the world. Mycobacterium tuberculosis is a facultative intracellular bacterium, possesses an exclusive life-cycle inside the macrophages, as one of the most important cells in the innate immune system. As soon as entrance in the lungs, bacteria actively replicate, but intracellular conditions such as hypoxia and nutrient starvation, lead to low replication of bacteria, or nonreplicating state. While Bacillus Calmette-Guerin vaccine is the most usable vaccine, especially in children and against active form, but this vaccine has no more protection in infected adults to latent forms of disease. Among the new generation of vaccines, fusion multistage subunit vaccines have prodigious effect on immune responses. By virtue of simultaneous presence of both expressed antigens from active and latent forms of TB in the structure of these recombinant subunit vaccines, they can strongly induce immune responses against all stages of the disease. The findings suggest subunit vaccines are the best candidates for immunization against TB, by virtue of their high safety, ease of production, specificity, and utilization of mycobacterial immunodominant antigens. Fusion multistage subunit vaccines, as novel subunit vaccines are the most ideal target for proper prevention against TB infection. Due to simultaneous use of both expressed antigens in active and latent forms of TB, these vaccines are able to induce strong immune responses versus all of TB stages. Copyright 2020 Wolters Kluwer Health, Inc. All rights reserved.

Overview of multistage subunit tuberculosis vaccines: advantages and challenges

Background: Plasmid and chromosomal extended-spectrum beta-lactamases (ESBLs) have been increasingly spread everywhere and blaCTX-M1 is one predominant beta-lactamase. Objectives: This study was fulfilled to determine the production of ESBL and prevalence of blaCTX-M1, blaSHV, and blaTEM among Escherichia coli blood isolates in Tehran. Patients and Methods: Twenty-three isolates were adopted to be studied during 2015-2016. The antibiotic susceptibility testing was performed using Kirby–Bauer method. The combined disk method was used for the detection of phenotypic ESBL production. The most effective antibiotics were piperacillin, amikacin, and ofloxacin. The minimum inhibitory concentration (MIC) of ceftazidime was determined using micro-broth dilution method. Polymerase chain reaction (PCR) was used for detecting the blaCTX-M1, blaSHV, and blaTEM genes. Results: In the broth dilution test, 19 (82%) isolates showed MIC ≥1, and 18 (78.3%) isolates were ceftazidime resistant. In the combined disk test, 19 (82%) isolates were ESBL producers. The results of the MIC and ceftazidime resistance were the same for ESBL selection. The results of MIC, in fact confirmed the disk diffusion in determining the phenotypic ESBL production. The frequency of blaCTX-M1, blaSHV, and blaTEM genes among blood ESBL producing isolates was 26% (n = 6), 8.6% (n = 2), and 0%, respectively. Isolates that showed higher MIC were positive for these genes. Conclusion: The prevalence of multidrug-resistant blood isolates and ESBL phenotype was high in military hospitals. A low number of blood strains amplified blaCTXM1 and blaSHV type beta–lactamases. There was a relationship between the MIC and the presence of beta-lactamase genes.

https://enterpathog.abzums.ac.ir/PDF/ijep-20161017102242

Antibiotic Susceptibility Profile, ESBL Production and blaCTX-M1, blaSHV and blaTEM Types Among Escherichia coli Blood Isolates

Objective : Silymarin and curcumin antimicrobial properties have been previously described against some infectious agents. The aims of the current study were the investigation of the antibacterial effects of these compounds on the expression of fimA, cdt, blaIMP1 and blaOXA-48 and AcrAB-TolC genes among multidrug-resistant Escherichia coli clinical isolates. Methods : A total of five carbapenemase-producing E. coli strains were included. All of them carried blaIMP1 and blaOXA-48, ACR-AB, cdt, fimA and QepA genes. The antibiotic susceptibility test, imipenem, cefotaxime and ceftazidime minimum inhibitory concentration (MIC) and combine disk and Carba NP-test for carbapenemase production were performed. Silymarin and curcumin minimum inhibitory and bactericidal concentrations [MIC and minimum bactericidal concentration (MBC), respectively] were determined. The effect of 25 &mgr;g/ml concentration was also evaluated against gene expression. The quantitative real-time PCR was performed for the evaluation of genes expression. Results : Silymarin MIC and MBC were 256 and more than 256 &mgr;g/ml, respectively. Moreover, curcumin MIC and MBC concentrations were 128 and 256 &mgr;g/ml, respectively. Silymarin down-expressed the ACR-AB, cdt, fimA genes and QepA genes significantly (P < 0.05), but conferred no significant effect on blaIMP nor blaOXA-48 genes. Moreover, curcumin down-expressed the ACR-AB, QepA and blaIMP genes significantly (P < 0.05), but exhibited no significant effect against blaOXA-48, cdt and fimA genes. Conclusion : In this study, curcumin and silymarin sub-MIC concentrations could significantly inhibit the expression of the ACR-AB, cdt, fimA, QepA and blaIMP genes at 25 &mgr;g/ml. Combating bacterial virulence is a proper strategy not only to inhibit the spread of infections, but also to prevent the appearance and spread of antibiotic nonsusceptible strains.

Silymarin and curcumin effects on virulence and carbapenemase genes among multidrug-resistant Escherichia coli clinical isolates

Akkermansia muciniphila (A. muciniphila) is a mucin-degrading bacterium that commonly lives in the intestinal mucus layer. It is normally detected in human faecal specimens and is one of the few bacteria potentially associated to obesity development. In this narrative review, possible mechanisms that support how A. muciniphila is implicated in the pathogenesis of obesity and metabolic-associated disease are described with the evaluation of its role as an intermediary or independent agent whose manipulation could be useful in the management of metabolic disorders. The ampleness of A. muciniphila is notably diminished in obesity, type 2 diabetes (T2D), non-alcoholic fatty liver disease (NAFLD), cardiometabolic diseases and low-grade inflammation. Furthermore, an inverse relationship between A. muciniphila, body weight and insulin sensitivity has been observed in both humans and animals. Antidiabetic drugs, gastric bypass surgery, prebiotics and biologically active compounds, such as polyphenols or saponins, have been shown to be associated with A. muciniphila relative abundance and thus could have favourable effects on metabolic disorders. Furthermore, A. muciniphila supplementation alone has been correlated with weight reduction and improvement of metabolic disorders, including fat mass gain, adipose tissue inflammation, metabolic endotoxaemia, and insulin resistance. Nevertheless, since the primary beneficial impacts of this bacterium have been predominantly investigated in various preclinical models, these results need to be confirmed in randomized clinical trials.

Akkermansia muciniphila as a novel powerful bacterial player in the treatment of metabolic disorders.

The recently identified 2019 novel coronaviruses (2019-nCoV) has caused extra-human infections. 2019-nCoV identified a global threat that is causing an outbreak of unusual viral pneumonia in patients with severe acute respiratory syndrome (SARS)-coronaviruses 2 (SARS-CoV-2). Considering the relatively high identity of the receptor-binding domain (RBD) in 2019-nCoV and SARS-CoV, it is urgent to assess the cross-reactivity of anti-SARS-CoV antibodies with 2019-nCoV spike protein, which could have important implications for rapid development of vaccines and therapeutic antibodies against 2019-nCoV. The zinc metal lopeptidase angiotensin-converting enzyme 2 (ACE2) is the only known human homolog of the key regulator of blood pressure ACE. ACE2 also serves as the cellular entry point for the SARS virus, therefore, a prime target for pharmacological intervention. SARS-CoV-2 uses the SARS-CoV receptor for entry and the serine protease transmembrane protease serine 2 for spike (S) protein priming. That it is still necessary to develop novel mAbs that could bind specifically to 2019-nCoV RBD. Cell entry of coronaviruses depends on the binding of the viral S proteins to cellular receptors and S protein priming by host cell proteases. A transmembrane protease serine 2 inhibitor approved for clinical use blocked entry and might constitute a treatment option. Our results reveal important commonalities between SARS-CoV-2 and SARS-CoV infection and identify a potential target for antiviral intervention. This review will help understand the biology and potential risk of CoVs that exist in richness in wildlife such as bats. We provide a brief introduction to the pathogenesis of SARS-CoV and Middle East respiratory syndrome-Coy and interaction between the RBD of coronavirus spike protein and ACE2. Copyright (C) 2021 Wolters Kluwer Health, Inc. All rights reserved.

Majid Eslami

Papers

Overview of multistage subunit tuberculosis vaccines: advantages and challenges

Antibiotic Susceptibility Profile, ESBL Production and blaCTX-M1, blaSHV and blaTEM Types Among Escherichia coli Blood Isolates

Silymarin and curcumin effects on virulence and carbapenemase genes among multidrug-resistant Escherichia coli clinical isolates

Akkermansia muciniphila as a novel powerful bacterial player in the treatment of metabolic disorders.

Genetic and structure of novel coronavirus COVID-19 and molecular mechanisms in the pathogenicity of coronaviruses