CD34+CD10+CD19- Cells in Patients with Unhealthy Alcohol Use Stimulate the M2b Monocyte Polarization.

M2b monocytes commonly isolated from patients with unhealthy alcohol use (Alc) have been described as cells that make the host susceptible to opportunistic infections. CD34+CD10+CD19- cells are multilineage progenitors of CD19+ cells, and we show that the effect of these cells from the peripheral blood on M2b monocyte polarization differed between healthy donors and Alc in this study. In healthy donors, these cells consistently differentiated into high-mobility group box-1 (HMGB1)-nonproducing cells (CD19+ cells) in response to retinoic acid (RA). However, owing to the lack of expression of RA receptor (RAR), these cells from Alc failed to differentiate into CD19+ cells under the same RA stimulation. Conditioned medium (CM) of these cells from Alc induced the polarization of M2b monocytes, which increases the susceptibility of hosts to opportunistic infections in Alc. When the alcoholic individuals were subjected to 2 weeks of abstinence from alcohol, these cells from Alc recovered their RAR expression and differentiated into CD19+ cells. Moreover, the CM of these cells from Alc after abstinence lost its ability to induce M2b monocyte polarization. These results indicate that these cells from Alc have different properties from those of healthy donors. In Alc, these cells without RAR stimulate M2b monocyte polarization through the production of HMGB1.

Murine response to the opportunistic bacterium Pseudomonas aeruginosa infection in gut dysbiosis caused by 5-fluorouracil chemotherapy-induced mucositis.

AIMS: This manuscript aims to explain the relationship between mucositis caused by 5-FU over gut bacterial species and susceptibility to opportunistic infection caused by P. aeruginosa. MAIN METHODS: BALB/c mice were intraperitoneally treated with PBS or 5-FU. Bodyweight and faecal consistency were checked daily. Mice faecal DNA was extracted, and bacterial phylogenetic groups were analysed using qPCR or high-throughput sequencing. Immunofluorescence was used to evaluate BMDM activation by mice-treated faecal content. Mice were challenged intratracheally with virulent P. aeruginosa, and the CFU and histology were analysed. Faecal microbiota were transplanted to evaluate the gut microbiota and resistance to pulmonary P. aeruginosa recovery. KEY FINDINGS: The animals treated with 5-FU presented mucositis with great weight loss, altered faecal consistency, bacterial gut dysbiosis and histological changes in the intestinal mucosa. Mice under 5-FU treatment were more susceptible to lung infection by the bacteria P. aeruginosa and had more extensive tissue damage during their lung infection with greater pro-inflammatory gene expression. It was observed that the mucositis remained in the groups with 5-FU even with the FMT. The results caused by mucositis in animals that received allogeneic FMT were reversed, however, with a decrease in P. aeruginosa susceptibility in animals treated with 5-FU and allogeneic FMT compared to animals treated with 5-FU and autologous FMT. SIGNIFICANCE: Treatment with 5-FU in a murine model makes it more susceptible to pulmonary infection by the bacterium P. aeruginosa, FMT offers an opportunity to protect against this susceptibility to infection.

MDA5 signaling induces type 1 IFN- and IL-1-dependent lung vascular permeability which protects mice from opportunistic fungal infection.

Lungs balance threat from primary viral infection, secondary infection, and inflammatory damage. Severe pulmonary inflammation induces vascular permeability, edema, and organ dysfunction. We previously demonstrated that poly(I:C) (pICLC) induced type 1 interferon (t1IFN) protected mice from Cryptococcus gattii (Cg) via local iron restriction. Here we show pICLC increased serum protein and intravenously injected FITC-dextran in the lung airspace suggesting pICLC induces vascular permeability. Interestingly, pICLC induced a pro-inflammatory signature with significant expression of IL-1 and IL-6 which depended on MDA5 and t1IFN. Vascular permeability depended on MDA5, t1IFN, IL-1, and IL-6. T1IFN also induced MDA5 and other MDA5 signaling components suggesting that positive feedback contributes to t1IFN dependent expression of the pro-inflammatory signature. Vascular permeability, induced by pICLC or another compound, inhibited Cg by limiting iron. These data suggest that pICLC induces t1IFN which potentiates pICLC-MDA5 signaling increasing IL-1 and IL-6 resulting in leakage of antimicrobial serum factors into lung airspace. Thus, induced vascular permeability may act as an innate defense mechanism against opportunistic fungal infection, such as cryptococcosis, and may be exploited as a host-directed therapeutic target.

Iron Assimilation during Emerging Infections Caused by Opportunistic Fungi with emphasis on Mucorales and the Development of Antifungal Resistance.

Iron is a key transition metal required by most microorganisms and is prominently utilised in the transfer of electrons during metabolic reactions. The acquisition of iron is essential and becomes a crucial pathogenic event for opportunistic fungi. Iron is not readily available in the natural environment as it exists in its insoluble ferric form, i.e., in oxides and hydroxides. During infection, the host iron is bound to proteins such as transferrin, ferritin, and haemoglobin. As such, access to iron is one of the major hurdles that fungal pathogens must overcome in an immunocompromised host. Thus, these opportunistic fungi utilise three major iron acquisition systems to overcome this limiting factor for growth and proliferation. To date, numerous iron acquisition pathways have been fully characterised, with key components of these systems having major roles in virulence. Most recently, proteins involved in these pathways have been linked to the development of antifungal resistance. Here, we provide a detailed review of our current knowledge of iron acquisition in opportunistic fungi, and the role iron may have on the development of resistance to antifungals with emphasis on species of the fungal basal lineage order Mucorales, the causative agents of mucormycosis.

Gastric Ulceration and Immune Suppression in Weaned Piglets Associated with Feed-Borne Bacillus cereus and Aspergillus fumigatus.

As a multifactorial cause, gastric ulceration-mediated diarrhea is widely prevalent in the weaned piglets, impairing pig health and economic benefits. With full implementation of antibiotic stewardship programs in China, Bacillus cereus (B. cereus) and Aspergillus fumigatus (A. fumigatus) were identified frequently in porcine feedstuffs and feeds of the animal industry. Association between feed-borne B. cereus and frequent diarrhea remains unclear. In the present study, we conducted a survey of B. cereus and A. fumigatus from feeds and feedstuffs in pig farms during hot season. Interestingly, B. cereus, B. subtilis, B. licheniformis and B. thuringinesis were isolated and identified from piglets' starter meals to sow feeds, accounting for 56.1%, 23.7%, 13.7% and 6.5%, respectively. Obviously, both B. cereus and B. subtili were dominant contaminants in the survey. In an in vitro study, Deoxynivalenol (DON) contents were determined in a dose-dependent manner post fermentation with B. cereus (405 and DawuC). Subsequently, 36 weaned piglets were randomly assigned to four groups and the piglets simultaneously received the combination of virulent B. cereus (Dawu C) and A. fumigatus while animals were inoculated with B. cereus (Dawu C), A. fumigatus or PBS as the control group. Clinically, piglets developed yellow diarrhea on day 5 and significant reductions of relative body weight were observed in the B. cereus group, and co-infection group. More importantly, IgG titers against Classical swine fever virus (CSFV) and Porcine epidemic diarrhea (PED) were reduced dramatically during 14-day observation in co-infection group, the B. cereus (Dawu C) group or the A. fumigatus group. However, lower Foot and mouth disease (FMD) -specific antibodies were reduced on day 7 compared to those of the control group. Additionally, lower lymphocyte proliferations were found in the B. cereus group and the co-infection group compared to the control group. Postmortem, higher lesions of gastric ulceration were observed in the B. cereus group and the co-infection group from day 7 to day 14 compared with those of the A. fumigatus group and the control group. Compared to the A. fumigatus group, higher DON contents were detected in the stomach inoculated with B. cereus and the co-infection with A. fumigatus. In conclusion, our data support the hypothesis that B. cereus might be associated with severe diarrhea by inducing gastric ulcerations and A. fumigatus might aggravate immune suppression, threating a sustainable swine industry. It is urgently needed to control feed-borne B. cereus contamination.

[Functional immunoassays in the setting of infectious risk and immunosuppressive therapy of non-HIV immunocompromised patients]. / Place des tests immunitaires fonctionnels dans la prise en charge du risque infectieux et de la gestion des thérapies immunosuppressives chez les patients immunodéprimés non-VIH.

The holistic approach of the human immune system is based on the study of its components collectively driving a functional response to an immunogenic stimulus. To appreciate a specific immune dysfunction, a condition is mimicked ex vivo and the immune response induced is assessed. The application field of such assays are broad and expanding, from the diagnosis of primary and secondary immunodeficiencies, immunotherapy for cancer to the management of patients at-risk for infections and vaccination. These assays are immune monitoring tools that may contribute to a personalised and precision medicine. The purpose of this review is to describe immune functional assays available in the setting of non-HIV acquired immune deficiency. First, we will address the use of theses assays in the diagnosis of opportunistic infections such as viral reactivation. Secondly, we will report the usefulness of these assays to assess vaccine efficacy and to manage immunosuppressive therapies.

Cryptides Identified in Human Apolipoprotein B as New Weapons to Fight Antibiotic Resistance in Cystic Fibrosis Disease.

Chronic respiratory infections are the main cause of morbidity and mortality in cystic fibrosis (CF) patients, and are characterized by the development of multidrug resistance (MDR) phenotype and biofilm formation, generally recalcitrant to treatment with conventional antibiotics. Hence, novel effective strategies are urgently needed. Antimicrobial peptides represent new promising therapeutic agents. Here, we analyze for the first time the efficacy of three versions of a cryptide identified in human apolipoprotein B (ApoB, residues 887-922) towards bacterial strains clinically isolated from CF patients. Antimicrobial and anti-biofilm properties of ApoB-derived cryptides have been analyzed by broth microdilution assays, crystal violet assays, confocal laser scanning microscopy and scanning electron microscopy. Cell proliferation assays have been performed to test cryptide effects on human host cells. ApoB-derived cryptides have been found to be endowed with significant antimicrobial and anti-biofilm properties towards Pseudomonas and Burkholderia strains clinically isolated from CF patients. Peptides have been also found to be able to act in combination with the antibiotic ciprofloxacin, and they are harmless when tested on human bronchial epithelial mesothelial cells. These findings open interesting perspectives to cryptide applicability in the treatment of chronic lung infections associated with CF disease.

Pathogen-Specific T Cells Beyond CMV, EBV and Adenovirus.

PURPOSE OF REVIEW: Infectious diseases contribute significantly to morbidity and mortality in recipients of allogeneic haematopoietic stem cell transplantation (aHSCT), particularly in the era of highly immunosuppressive transplant regimens and alternate donor transplants. Delayed cellular immune recovery is a major mechanism for the increased risk in these patients. Adoptive cell therapy with ex vivo manipulated pathogen-specific T cells (PSTs) is increasingly taking its place as a treatment strategy using donor-derived or third party-banked cells. RECENT FINDINGS: The majority of clinical trial data in the form of early-phase studies has been in the prophylaxis or treatment of cytomegalovirus (CMV), Epstein-Barr virus (EBV) and adenovirus (AdV). Advancements in methods to select and enrich PSTs offer the opportunity to target the less common viral pathogens as well as fungi with this technology. Early clinical studies of PSTs targeting polyomaviruses (BK virus and JC virus), human herpesvirus 6 (HHV6), varicella zoster virus (VZV) and Aspergillus spp. have shown promising results in small numbers of patients. Other potential targets include herpes simplex virus (HSV), respiratory viruses and other invasive fungal species. In this review, we describe the burden of disease of this wider spectrum of pathogens, the progress in the development of manufacturing capability, early clinical results and the opportunities and challenges for implementation in the clinic.

Resolving the pathogenicity factors of a novel opportunistic fungus Schizophyllum commune at molecular level.

Schizophyllum commune is a well-known mushroom forming fungi which is an edible one due to its nutritive value. It exhibits a special wood degrading mechanism to grow in decay matters by releasing a series of enzymes. These enzymes might make them an opportunistic pathogen which has been reported to infect various animals and human beings too. Although these fungi were identified as human and animal pathogens, their mechanisms of pathogenesis and the key virulence factors involved in disease establishment are not known. In this study, we reported this fungal infection in freshwater fish for the first time and its morphological features. Further, we employed RNA-seq technique to identify the major virulence factors involved in the pathogenesis in fish and the network of interaction between the identified virulence factors were analysed. Also, we confirmed the virulence roles of this fungus during infection by qRT-PCR analysis. This study emphasizes the virulence nature of the common mushroom forming food fungus and the involvement of enzymes such as phosphoinositide phospholipase C, hexosaminidase and few toxins such as pesticidal and insecticidal crystal proteins which opened a new avenue in the virulence nature of edible mushrooms.

The Interaction of Human Pathogenic Fungi With C-Type Lectin Receptors.

Fungi, usually present as commensals, are a major cause of opportunistic infections in immunocompromised patients. Such infections, if not diagnosed or treated properly, can prove fatal. However, in most cases healthy individuals are able to avert the fungal attacks by mounting proper antifungal immune responses. Among the pattern recognition receptors (PRRs), C-type lectin receptors (CLRs) are the major players in antifungal immunity. CLRs can recognize carbohydrate ligands, such as ß-glucans and mannans, which are mainly found on fungal cell surfaces. They induce proinflammatory immune reactions, including phagocytosis, oxidative burst, cytokine, and chemokine production from innate effector cells, as well as activation of adaptive immunity via Th17 responses. CLRs such as Dectin-1, Dectin-2, Mincle, mannose receptor (MR), and DC-SIGN can recognize many disease-causing fungi and also collaborate with each other as well as other PRRs in mounting a fungi-specific immune response. Mutations in these receptors affect the host response and have been linked to a higher risk in contracting fungal infections. This review focuses on how CLRs on various immune cells orchestrate the antifungal response and on the contribution of single nucleotide polymorphisms in these receptors toward the risk of developing such infections.

Impaired Secretion of TNF-α by Monocytes Stimulated With EBV Peptides Associates With Infectious Complications After Kidney Transplantation.

BACKGROUND: The successful development of immunosuppressive agents has paradoxically led to an era in which adverse effects of immunosuppression, such as infections and cancer, are now a major concern in solid organ recipients. Nevertheless, the main focus of immune monitoring research remains the identification of rejection. There is currently no clinical tool to assess the net state of immunosuppression or to identify patients at increased risk of infectious complications. METHODS: We report a prospective, longitudinal study in which we conducted detailed phenotyping of over 300 peripheral blood mononuclear cell samples from 45 kidney recipients during the first 24 months posttransplant. Patients were classified as cases or controls according to the following events: an opportunistic infection, recurring bacterial infections, or de novo neoplasia. RESULTS: Using a training cohort, an exploratory analysis revealed that the TNFα response to synthetic Epstein-Barr virus peptides by CD14CD16 monocytes was lower in cases. A classifier rule based on 2 or greater consecutive values below a threshold of 73% of TNFα-positive cells provided a sensitivity and specificity of 83%. In the validation cohort, the assay exhibited a sensitivity of 90% and a specificity of 63%. Analysis of IFNγ responses by T cells showed no correlation with the cases' phenotype. The association between overimmunosuppression status and the monocyte response was independent of age, renal function, and immunosuppressive regimen. CONCLUSIONS: These data suggest that patients with infectious complications posttransplantation have lower CD14CD16 monocyte responses to Epstein-Barr virus peptides. This assay seems promising to help personalize the immunotherapy.

Addressing Antiretroviral Therapy-Associated Drug-Drug Interactions in Patients Requiring Treatment for Opportunistic Infections in Low-Income and Resource-Limited Settings.

An increasing number of human immunodeficiency virus (HIV)-infected patients are achieving virologic suppression on antiretroviral therapy (ART) limiting the use of primary and secondary antimicrobial prophylaxis. However, in low-income and resource-limited settings, half of those infected with HIV are unaware of their diagnosis, and fewer than 50% of patients on ART achieve virologic suppression. Management of comorbidities and opportunistic infections among patients on ART may lead to inevitable drug-drug interactions (DDIs) and even toxicities. Elderly patients, individuals with multiple comorbidities, those receiving complex ART, and patients living in low-income settings experience higher rates of DDIs. Management of these cytochrome P450-mediated, nonmediated, and drug transport system DDIs is critical in HIV-infected patients, particularly those in resource-limited settings with few options for ART. This article critically analyzes and provides recommendations to manage significant DDIs and drug toxicities in HIV-infected patients receiving ART.

Lung Infections in Systemic Rheumatic Disease: Focus on Opportunistic Infections.

Systemic rheumatic diseases have significant morbidity and mortality, due in large part to concurrent infections. The lung has been reported among the most frequent sites of infection in patients with rheumatic disease, who are susceptible to developing pneumonia sustained both by common pathogens and by opportunistic microorganisms. Patients with rheumatic disease show a peculiar vulnerability to infectious complications. This is due in part to intrinsic disease-related immune dysregulation and in part to the immunosuppressive treatments. Several therapeutic agents have been associated to a wide spectrum of infections, complicating the management of rheumatic diseases. This review discusses the most frequent pulmonary infections encountered in rheumatic diseases, focusing on opportunistic agents, consequent diagnostic challenges and appropriate therapeutic strategies.

Cytokine Expression Profile as Predictive Surrogate Biomarkers for Clinical Events in the Field of Solid Organ Transplantation.

The morbidity and mortality after solid organ transplantation leads to poor outcomes in the long-term graft survival. There are many sources increasing bad outcomes within the post-transplant period reducing the quality of recipient´s life, such as rejection episodes, opportunistic infections as well as immunosuppression related morbidity. A complete understanding on the immune system responses against the allo-graft remains unknown. Recently, some pro-inflammatory cytokines, such as IFN-γ and IL-17, as well as IL-2, have been proposed as surrogate biomarkers able to predict the appearance of clinical event episodes. In this review we summarize the latest findings regarding the immune function monitoring in solid organ transplantation as well as the most common techniques (ELISPOT, ELISA and Flow Cytometry) that have been widely used across different clinical laboratories.

Relation between neonatal malnutrition and gene expression: inflammasome function in infections caused by Candida Albicans.

PURPOSE: To investigate the effects of neonatal malnutrition followed by nutritional replacement on the signaling mechanisms developed by the inflammasome complex by analyzing the expression of the targeted TLR2, TLR4, NLRP3, caspase-1 and release of IL-1ß and IL-18 by alveolar macrophages infected in vitro with Candida albicans. METHODS: Male Wistar rats (n = 24), 90-120 days, were suckled by mothers whose diet during lactation contained 17 % protein in the nourish group and 8 % protein in the malnourished group. After weaning, both groups were fed a normal protein diet. Macrophages were obtained after tracheostomy, through the collection of bronchoalveolar lavage fluid. The quantification of the expression levels of targets (TLR2, TLR4, NLRP3 and caspase-1) was performed by real-time RT-PCR. Production of cytokines was performed by ELISA. RESULTS: The malnourished animals during lactation showed reduced body weight from the fifth day of life, remaining until adulthood. Further, the model applied malnutrition induced a lower expression of TLR4 and caspase-1. The quantification of the TLR2 and NLRP3, as well as the release of IL-1ß and IL-18, was not different between groups of animals nourished and malnourished. The system challenged with Candida albicans showed high expression levels of all targets in the study. CONCLUSIONS: The tests demonstrate nutritional restriction during critical periods of development, although nutritional supplementation may compromise defense patterns in adulthood in a timely manner, preserving distinct signaling mechanism, so that the individual does not become widely vulnerable to infections by opportunistic pathogens.

Intravenous Antibiotic and Antifungal Agent Pharmacokinetic-Pharmacodynamic Dosing in Adults with Severe Burn Injury.

PURPOSE: Despite advances in the care of patients with severe burn injury, infection-related morbidity and mortality remain high and can potentially be reduced with antimicrobial dosing optimized for the infecting pathogen. However, anti-infective dose selection is difficult because of the highly abnormal physiologic features of burn patients, which can greatly affect the pharmacokinetic (PK) disposition of these agents. We review published PK data from burn patients and offer evidence-based dosing recommendations for antimicrobial agents in burn-injured patients. METHODS: Because most infections occur at least 48 hours after initial burn injury and anti-infective therapy often lasts ≥10 days, we reviewed published data informing PK-pharmacodynamic (PD) dosing of anti-infectives administered during the second, hypermetabolic stage of burn injury, in those with >20% total body surface area burns, and in those with normal or augmented renal clearance (estimated creatinine clearance ≥130 mL/min). Analyses were performed using 10,000-patient Monte Carlo simulations, which uses PK variability observed in burn patients and MIC data to determine the probability of reaching predefined PK-PD targets. The probability of target attainment, defined as the likelihood that an anti-infective dosing regimen would achieve a specific PK-PD target at the single highest susceptible MIC, and the cumulative fraction of response, defined as the population probability of target attainment given a specific dose and a distribution of MICs, were calculated for each recommended anti-infective dosing regimen. FINDINGS: Evidence-based doses were derived for burn-injured patients for 15 antibiotics and 2 antifungal agents. Published data were unavailable or insufficient for several agents important to the care of burn patients, including newer antifungal and antipseudomonal agents. Furthermore, available data suggest that antimicrobial PK properties in burned patients is highly variable. We recommend that, where possible, therapeutic drug monitoring be performed to optimize PK-PD parameter achievement in individual patients. IMPLICATIONS: Given the high variability in PK disposition observed in burn patients, doses recommended in the package insert may not achieve PK-PD parameters associated with optimal infectious outcomes. Our study is limited by the necessity for fixed assumptions in depicting this highly variable patient population. New rapid-turnaround analytical technology is needed to expand the menu of antimicrobial agents for which therapeutic drug monitoring is available to guide dose modification within a clinically actionable time frame.