Fungal Translocation Research Articles

Gut mycobiome alterations and implications for liver diseases.

Chronic liver disease and its complications are a significant global health burden. Changes in fungal communities (mycobiome), an integral component of the gut microbiome, are associated with and contribute to the development of liver disease. Fungal dysbiosis can induce intestinal barrier dysfunction and allow fungal products to translocate to the liver causing progression of disease. This review explores recent progress in understanding the compositional and functional diversity of gut mycobiome signatures across different liver diseases. It delves into causative connections between gut fungi and liver diseases. We emphasize the significance of fungal translocation, with a particular focus on fungal-derived metabolites and immune cells induced by fungi, as key contributors to liver disease. Furthermore, we review the potential impact of the intrahepatic mycobiome on the progression of liver diseases.

Modeling of intravenous caspofungin administration using an intestine-on-chip reveals altered Candida albicans microcolonies and pathogenicity

Candida albicans is a commensal yeast of the human intestinal microbiota that, under predisposing conditions, can become pathogenic and cause life-threatening systemic infections (candidiasis). Fungal-host interactions during candidiasis are commonly studied using conventional 2D in vitro models, which have provided critical insights into the pathogenicity. However, microphysiological models with a higher biological complexity may be more suitable to mimic in vivo-like infection processes and antifungal drug efficacy. Therefore, a 3D intestine-on-chip model was used to investigate fungal-host interactions during the onset of invasive candidiasis and evaluate antifungal treatment under clinically relevant conditions. By combining microbiological and image-based analyses we quantified infection processes such as invasiveness and fungal translocation across the epithelial barrier. Additionally, we obtained novel insights into fungal microcolony morphology and association with the tissue. Our results demonstrate that C. albicans microcolonies induce injury to the epithelial tissue by disrupting apical cell-cell contacts and causing inflammation. Caspofungin treatment effectively reduced the fungal biomass and induced substantial alterations in microcolony morphology during infection with a wild-type strain. However, caspofungin showed limited effects after infection with an echinocandin-resistant clinical isolate. Collectively, this organ-on-chip model can be leveraged for in-depth characterization of pathogen-host interactions and alterations due to antimicrobial treatment.

Candida albicans translocation through the intestinal epithelial barrier is promoted by fungal zinc acquisition and limited by NFκB-mediated barrier protection.

The opportunistic fungal pathogen Candida albicans thrives on human mucosal surfaces as a harmless commensal, but frequently causes infections under certain predisposing conditions. Translocation across the intestinal barrier into the bloodstream by intestine-colonizing C. albicans cells serves as the main source of disseminated candidiasis. However, the host and microbial mechanisms behind this process remain unclear. In this study we identified fungal and host factors specifically involved in infection of intestinal epithelial cells (IECs) using dual-RNA sequencing. Our data suggest that host-cell damage mediated by the peptide toxin candidalysin-encoding gene ECE1 facilitates fungal zinc acquisition. This in turn is crucial for the full virulence potential of C. albicans during infection. IECs in turn exhibit a filamentation- and damage-specific response to C. albicans infection, including NFκB, MAPK, and TNF signaling. NFκB activation by IECs limits candidalysin-mediated host-cell damage and mediates maintenance of the intestinal barrier and cell-cell junctions to further restrict fungal translocation. This is the first study to show that candidalysin-mediated damage is necessary for C. albicans nutrient acquisition during infection and to explain how IECs counteract damage and limit fungal translocation via NFκB-mediated maintenance of the intestinal barrier.

Fungal translocation measured by serum 1,3-ß-D-glucan correlates with severity and outcome of liver cirrhosis-A pilot study.

On a global scale, liver cirrhosis is attributable to ~1 million deaths per year. This systemic disease comes along with diverse sequelae, including microbiota alterations, increased gut permeability and translocation of microbial components into the systemic circulation. Alongside the extensively studied influence of bacterial translocation and its host-pathogen interactions, far less is known about the role and impact of fungal components once having crossed the intestinal barrier. Including 70 patients with different aetiologies of liver cirrhosis, we investigated the relationship between fungal translocation, measured by 1,3-β-D-glucan (BDG), and biomarkers of gut integrity, inflammation and severity/outcome of liver disease. Patients with cirrhosis Child-Pugh class (CPC)-B were more likely to have positive serum BDG (aOR 5.4, 95% CI 1.2-25.2) compared to patients with cirrhosis CPC-A. BDG showed a moderate positive correlation with several markers of inflammation (sCD206, sCD163, Interleukin 8, interferon-gamma-induced protein). Mortality differed significantly between patients with positive versus negative BDG (log-rank test, p = 0.015). The multivariable Cox regression model yielded an aHR of 6.8 (95% CI 1.8-26.3). We observed trends for increased fungal translocation depending on the severity of liver cirrhosis, an association of BDG with an inflammatory environment and the adverse effects of BDG on disease outcome. In order to gain more in-depth knowledge about (fungal-)dysbiosis and its detrimental consequences in the setting of liver cirrhosis, these trends need to be studied in more detail including prospective sequential testing in larger cohorts together with mycobiome analyses. This will further elucidate complex host-pathogen interactions and potentially introduce points of application for therapeutic interventions.

Translocation of bacterial LPS is associated with self-reported cognitive abilities in men living with HIV receiving antiretroviral therapy

BackgroundGut damage allows translocation of bacterial lipopolysaccharide (LPS) and fungal β-D-glucan (BDG) into the blood. This microbial translocation contributes to systemic inflammation and risk of non-AIDS comorbidities in people living with HIV, including those receiving antiretroviral therapy (ART). We assessed whether markers of gut damage and microbial translocation were associated with cognition in ART-treated PLWH.MethodsEighty ART-treated men living with HIV from the Positive Brain Health Now Canadian cohort were included. Brief cognitive ability measure (B-CAM) and 20-item patient deficit questionnaire (PDQ) were administered to all participants. Three groups were selected based on their B-CAM levels. We excluded participants who received proton pump inhibitors or antiacids in the past 3 months. Cannabis users were also excluded. Plasma levels of intestinal fatty acid binding protein (I-FABP), regenerating islet-derived protein 3 α (REG3α), and lipopolysaccharides (LPS = were quantified by ELISA, while 1–3-β-D-glucan BDG) levels were assessed using the Fungitell assay. Univariable, multivariable, and splines analyses were performed.ResultsPlasma levels of I-FABP, REG3α, LPS and BDG were not different between groups of low, intermediate and high B-CAM levels. However, LPS and REG3α levels were higher in participants with PDQ higher than the median.Multivariable analyses showed that LPS association with PDQ, but not B-CAM, was independent of age and level of education. I-FABP, REG3α, and BDG levels were not associated with B-CAM nor PDQ levels in multivariable analyses.ConclusionIn this well characterized cohort of ART-treated men living with HIV, bacterial but not fungal translocation was associated with presence of cognitive difficulties. These results need replication in larger samples.

Markers of fungal translocation are elevated during post-acute sequelae of SARS-CoV-2 and induce NF-κB signaling.

Long COVID, a type of post-acute sequelae of SARS-CoV-2 (PASC), has been associated with sustained elevated levels of immune activation and inflammation. However, the mechanisms that drive this inflammation remain unknown. Inflammation during acute coronavirus disease 2019 could be exacerbated by microbial translocation (from the gut and/or lung) to blood. Whether microbial translocation contributes to inflammation during PASC is unknown. We did not observe a significant elevation in plasma markers of bacterial translocation during PASC. However, we observed higher levels of fungal translocation — measured as β-glucan, a fungal cell wall polysaccharide — in the plasma of individuals experiencing PASC compared with those without PASC or SARS-CoV-2–negative controls. The higher β-glucan correlated with higher inflammation and elevated levels of host metabolites involved in activating N-methyl-d-aspartate receptors (such as metabolites within the tryptophan catabolism pathway) with established neurotoxic properties. Mechanistically, β-glucan can directly induce inflammation by binding to myeloid cells (via Dectin-1) and activating Syk/NF-κB signaling. Using a Dectin-1/NF-κB reporter model, we found that plasma from individuals experiencing PASC induced higher NF-κB signaling compared with plasma from negative controls. This higher NF-κB signaling was abrogated by piceatannol (Syk inhibitor). These data suggest a potential targetable mechanism linking fungal translocation and inflammation during PASC.

Fungal Translocation Marker in People Living with HIV Needing Treatment for Onychomycosis: A Protocol for the Prospective Pilot Study

Abstract Increased microbial translocation and chronic immune activation are two critical problems for people living with HIV (PLWH) in the antiretroviral therapy (ART) era. Compared with numerous studies on bacterial microbiomic communities, there are only a limited number of studies focusing on fungal microbiomic composition and products in PLWH. This study protocol is used to evaluate the changes in bacterial and fungal microbiome populations induced by terbinafine treatment, which is an antifungal agent widely used amongst PLWH. Twenty-two PLWH on a stable ART regimen for more than six months, who require treatment for onychomycosis, will be recruited. The participants will be followed-up for a 12-week treatment period (oral terbinafine 250 mg daily) and another 12-weeks of terbinafine discontinuation. Plasma and fecal samples will be collected before and after terbinafine treatment, and for 12weeks after the discontinuation of terbinafine. Plasma gut injury and microbial translocation biomarker assays, in addition to testing for gut microbiome composition, will be undertaken. With this pilot study, we will perform formal sample size calculations and test study feasibility for a possible full-scale study.

Aging With Grace for People Living With HIV: Strategies to Overcome Leaky Gut and Cytomegalovirus Coinfection.

:The intestinal epithelial layer acts as a mechanical and functional barrier between the intraluminal microbiota and the immunologically active submucosa. A progressive loss of gut barrier function (leaky gut) leads to enhanced translocation of microbial products, which in turn contributes as endotoxins to inflammaging. Th17 T cell represents the main immune sentinels in the gut epithelium, preventing aggression from commensal and pathogenic microbes. As HIV infection deeply affects gut Th17 function and increases gut permeability, microbial translocation occurs at high level in people living with HIV (PLWH) and has been associated with the development of non-AIDS comorbidities. Although the inflammatory role of endotoxins like lipopolysaccharide produced by Gram-negative bacteria is well-established, fungal products such as β-D-glucan emerge as new contributors. In addition, PLWH are more frequently infected with cytomegalovirus (CMV) than the general population. CMV infection is a well-described accelerator of immune aging, through the induction of expansion of dysfunctional CD8 T-cells as well as through enhancement of gut microbial translocation. We critically review immune mechanisms related to bacterial and fungal translocation, with a focus on the contribution of CMV coinfection in PLWH. Improving gut barrier dysfunction, microbial composition, and reducing microbial translocation constitute emerging strategies for the prevention and treatment of HIV-associated inflammation and may be relevant for age-related inflammatory conditions.

80. Heme Oxygenase-1 Gene promoter and associations with inflammation and subclinical vascular disease in Ugandan adolescents with and without HIV

Abstract Background Heme oxygenase-1 (HO-1) is a cytoprotective enzyme with potent anti-inflammatory, and anti-oxidant effects. The HO-1 response is modulated by functional polymorphisms (a dinucleotide (GT)n repeat length variation) in the HO-1 gene promoter region which have been associated with cardiovascular disease (CVD) susceptibility in adults. HO-1 polymorphisms and their associations with markers of inflammation and CVD in Ugandan adolescents with (HIV+) and without HIV (HIV-) have not been investigated. Methods We included 177 children (92 HIV+, 85 HIV-) enrolled in an ongoing observational cohort study at the Joint Clinical Research Center, Kampala, Uganda. All HIV+ participants were on ART. HO-1 (GT)n allele genotypes were determined by PCR of the (GT)n repeat region followed by fragment size determination on a capillary sequencer in DNA extracted from blood samples. Allele designations were assigned by number of (GT)n repeats: S < 27, M 27-34, or L > 34 repeats. We measured mean common carotid artery intima-media thickness (IMT) as a marker of CVD, markers of systemic inflammation (hsCRP, IL6, sTNFRI), monocyte activation (sCD14 and sCD163), and T-cell activation (expression of CD38 and HLA-DR on CD4+ and CD8+) , oxidized lipids, markers of gut integrity and fungal translocation (BDG). Results Median age (IQR) was 13 (11, 14), 44% were females, 86% had viral load < 20 copies/mL. 19% had a short allele genotype, 37% had a medium allele genotype and 44% had a long allele genotype (Figure). The shortest and longest allele length correlated with lower IMT in HIV- only (r=-0.36 and -0.30, respectively, p≤ 0.01 for both). Among biomarkers, only the medium allele correlated with oxidized lipids in HIV+ and with hsCRP and BDG in HIV- (p≤ 0.05). After adjusting for age, sex, and BMI, the presence of a long allele was associated with lower IMT. This was no longer significant after adjusting for markers of inflammation or oxidized lipids (Table). Heme Oxygenase-1 genotype allele length frequency in Ugandan cohort of HIV+ and HIV- youth 1: Models are adjusted for age (years), sex (male vs female), BMI (kg/m2) and HIV status (positive vs negative) 2: Models are adjusted for age (years), sex (male vs female), BMI (kg/m2), sCD14 (pg/mL) and HIV status (positive vs negative) 3: Models are adjusted for age (years), sex (male vs female), BMI (kg/m2), high sensitivity C reactive protein (ng/mL) and HIV status (positive vs negative) 4: Models are adjusted for age (years), sex (male vs female), BMI (kg/m2), oxidized lipids and HIV status (positive vs negative) Conclusion These findings underscore the potential of the HO pathways in modulating future risk for CVD in adolescents through inflammation. HIV status in this setting, likely influences the associations with the genotype with the risk of CVD. Further studies to validate our findings in this population are required. Disclosures Grace A. McComsey, MD, Gilead (Consultant, Advisor or Review Panel member)Janssen (Consultant, Advisor or Review Panel member)Merck (Consultant, Grant/Research Support, Scientific Research Study Investigator, Advisor or Review Panel member)Redhill (Research Grant or Support)Roche (Grant/Research Support)Tetraphase, Astellas (Research Grant or Support)Theratechnologies (Consultant)Vanda (Grant/Research Support)ViiV/GSK (Scientific Research Study Investigator, Advisor or Review Panel member)

Opportunistic yeast pathogenCandidaspp.: Secreted and membrane-bound virulence factors

Candida virulence factors (VFs) including mainly enzymes and proteins play vital roles in breaching the human intestinal barrier and causing deadly invasive candidiasis. Limited VFs' structural studies hinder deeper comprehension of their mechanisms and thus the design of vaccines and antifungal drugs against fungal infections.

Advanced baseline immunosuppression is associated with elevated levels of plasma markers of fungal translocation and inflammation in long-term treated HIV-infected Tanzanians

BackgroundFor over a decade, antiretroviral therapy (ART) in resource-limited countries was only recommended for patients with advanced HIV disease. We investigated this group of patients in order to determine any relationship between degree of immunosuppression during treatment initiation and the subsequent levels of inflammatory biomarkers, reservoir size and plasma marker of fungal translocation after achieving long-term virological control.MethodsWe analyzed 115 virally suppressed (female 83.5%) and 40 untreated (female 70%) subjects from Dar es Salaam, Tanzania. The size of HIV latent reservoir (proviral DNA copy) was determined using quantitative PCR. Inflammatory biomarkers; IL-6, IL-10, and soluble CD14 (sCD14), were measured using multiplex cytometric beads array. Antibody titers for Cytomegalovirus (CMV) and Epstein Barr virus (EBV), plasma level of 1-3-beta-d-Glucan (BDG) was measured using ELISA. High-sensitivity C-reactive protein (hsCRP) was measured using nephelometric method.ResultsThe median age was 36 (IQR 32-44) and 47 (IQR 43–54) years in untreated and virally suppressed patients respectively. Median duration of treatment for virally suppressed patients was 9 years (IQR 7–12) and median baseline CD4 count was 147 cells/mm3 (IQR 65–217). Virally suppressed patients were associated with significantly lower plasma levels of IL-10, sCD14 and BDG (P < 0.05) when compared to untreated patients. However, plasma level of IL-6 was similar between the groups. Baseline advanced level of immunosuppression (CD4 < 100cells/cm3) was associated with significantly higher plasma level of IL-6 (P = 0.02), hsCRP (P = 0.036) and BDG (P = 0.0107). This relationship was not seen in plasma levels of other tested markers. Degree of baseline immunosuppression was not associated with the subsequent proviral DNA copy. In addition, plasma levels of inflammatory marker were not associated with sex, CMV or EBV antibody titers, treatment duration or regimen.ConclusionsOur data suggest that advanced immunosuppression at ART initiation is associated with severity of inflammation and elevated fungal translocation marker despite long term virological control. Further studies are needed to evaluate the potential increased burden of non-AIDS comorbidities that are linked to elevated inflammatory and fungal translocation markers as a result of the policy of HIV treatment at CD4 count < 200 cells/cm3 implemented for over a decade in Tanzania.

Gut Leakage of Fungal-Related Products: Turning Up the Heat for HIV Infection.

The intestinal epithelial layer serves as a physical and functional barrier between the microbiota in the lumen and immunologically active submucosa. Th17 T-cell function protects the gut epithelium from aggression from microbes and their by-products. Loss of barrier function has been associated with enhanced translocation of microbial products which act as endotoxins, leading to local and systemic immune activation. Whereas the inflammatory role of LPS produced by Gram-negative bacteria has been extensively studied, the role of fungal products such as β-D-glucan remains only partially understood. As HIV infection is characterized by impaired gut Th17 function and increased gut permeability, we critically review mechanisms of immune activation related to fungal translocation in this viral infection. Additionally, we discuss markers of fungal translocation for diagnosis and monitoring of experimental treatment responses. Targeting gut barrier dysfunction and reducing fungal translocation are emerging strategies for the prevention and treatment of HIV-associated inflammation and may prove useful in other inflammatory chronic diseases.

Uremia Coupled with Mucosal Damage Predisposes Mice with Kidney Disease to Systemic Infection by Commensal Candida albicans.

Infections are the second major cause of mortality in patients with kidney disease and accompanying uremia. Both vascular access and non-access-related infections contribute equally to the infection-related deaths in patients with kidney disease. Dialysis is the most common cause of systemic infection by Candida albicans in these patients. C albicans also reside in the gastrointestinal tract as a commensal fungus. However, the contribution of gut-derived C albicans in non-access-related infections in kidney disease is unknown. Using a mouse model of kidney disease, we demonstrate that uremic animals showed increased gut barrier permeability, impaired mucosal defense, and dysbiosis. The disturbance in gut homeostasis is sufficient to drive the translocation of microbiota and intestinal pathogen Citrobacter rodentium to extraintestinal sites but not C albicans Interestingly, a majority of uremic animals showed fungal translocation only when the gut barrier integrity is disrupted. Our data demonstrate that uremia coupled with gut mucosal damage may aid in the translocation of C. albicans and cause systemic infection in kidney disease. Because most of the individuals with kidney disease suffer from some form of gut mucosal damage, these results have important implications in the risk stratification and control of non-access-related opportunistic fungal infections in these patients.

Glucan rich nutrition does not increase gut translocation of beta-glucan.

(1-3)-b-D-glucan (BDG) is a fungal cell wall component and, in the absence of invasive fungal infection, a novel biomarker for microbial translocation of endogenous fungal products from the gastrointestinal tract into systemic circulation. However, its value as a marker of fungal translocation is limited by a concern that plant BDG-rich food influences blood BDG levels. We conducted a pilot clinical trial to evaluate the impact of a standardised oral BDG challenge on blood BDG levels in participants with and without elevated microbial translocation. We enrolled 14 participants including 8 with HIV infection, 2 with advanced liver cirrhosis, and 4 healthy controls. After obtaining a baseline blood sample, participants received a standardised milkshake containing high levels of BDG followed by serial blood samples up to 8hours after intake. The standardised oral BDG challenge approach did not change the blood BDG levels over time in all participants. We found consistently elevated blood BDG levels in one participant with advanced liver cirrhosis and a single person with HIV with a low CD4 count of 201cells/mm3 . Our findings indicate that BDG blood levels were not influenced by plant origin BDG-rich nutrition in PWH, people with advanced liver cirrhosis, or healthy controls. Future studies are needed to analyse gut mycobiota populations in individuals with elevated blood BDG levels.

Increased monocyte and T-cell activation in treated HIV+ Ugandan children: associations with gut alteration and HIV factors.

The pathophysiology of immune activation and its mechanisms in children living with perinatally acquired HIV (PHIV) in sub-Saharan Africa has been understudied. We enrolled 101 children living with PHIV and 96 HIV-negative controls (HIV-). All participants were between 10 and 18 years of age with no known active infections. PHIVs were on ART with HIV-1 RNA level 400 copies/ml or less. We measured plasma and cellular markers of monocyte activation, T-cell activation (expression of CD38 and HLA-DR on CD4 and CD8), oxidized lipids, markers of gut integrity and fungal translocation. Spearman correlations and linear regression models were used. Overall median (Q1; Q3) age was 13 years (11; 15) and 52% were girls. Groups were similar by age, sex and BMI. Median ART duration was 10 years (8; 11). PHIVs had higher monocyte and T-cell activation; higher sCD14 (P = 0.01) and elevated frequencies of nonclassical monocytes (P < 0.001 for both). Markers of systemic inflammation (hsCRP), fungal translocation (BDG), intestinal permeability (zonulin) and oxidized lipids (ox LDL) correlated with monocyte and T-cell activation in PHIV (≤0.05). After adjusting for age, sex, ART duration, protease inhibitor and nonnucleoside reverse transcriptase inhibitor use, a modest association between BDG and activated CD4 T cells was observed (β=0.65, P < 0.01). Oxidized LDL was inversely associated with activated T cells, inflammatory and nonclassical monocytes (P < 0.01). Ugandan children with perinatally acquired HIV with viral suppression have evidence of ongoing immune activation. Intestinal barrier dysfunction and fungal translocation may be involved in chronic immune dysfunction.

Daily variations of gut microbial translocation markers in ART-treated HIV-infected people

BackgroundIncreased intestinal barrier permeability and subsequent gut microbial translocation are significant contributors to inflammatory non-AIDS comorbidities in people living with HIV (PLWH). Evidence in animal models have shown that markers of intestinal permeability and microbial translocation vary over the course of the day and are affected by food intake and circadian rhythms. However, daily variations of these markers are not characterized yet in PLWH. Herein, we assessed the variation of these markers over 24 h in PLWH receiving antiretroviral therapy (ART) in a well-controlled environment.MethodsAs in Canada, PLWH are predominantly men and the majority of them are now over 50 years old, we selected 11 men over 50 receiving ART with undetectable viremia for more than 3 years in this pilot study. Blood samples were collected every 4 h over 24 h before snacks/meals from 8:00 in the morning to 8:00 the next day. All participants consumed similar meals at set times, and had a comparable amount of sleep, physical exercise and light exposure. Plasma levels of bacterial lipopolysaccharide (LPS) and fungal (1→3)-β-D-Glucan (BDG) translocation markers, along with markers of intestinal damage fatty acid binding protein (I-FABP) and regenerating islet-derived protein-3α (REG3α) were assessed by ELISA or the fungitell assay.ResultsParticipants had a median age of 57 years old (range 50 to 63). Plasma levels of BDG and REG3α did not vary significantly over the course of the study. In contrast, a significant increase of LPS was detected between 12:00 and 16:00 (Z-score: − 1.15 ± 0.18 vs 0.16 ± 0.15, p = 0.02), and between 12:00 and 24:00 (− 1.15 ± 0.18 vs 0.89 ± 0.26, p < 0.001). The plasma levels of I-FABP at 16:00 (− 0.92 ± 0.09) were also significantly lower, compared to 8:00 the first day (0.48 ± 0.26, p = 0.002), 4:00 (0.73 ± 0.27, p < 0.001) or 8:00 on secondary day (0.88 ± 0.27, p < 0.001).ConclusionsConversely to the fungal translocation marker BDG and the gut damage marker REG3α, time of blood collection matters for the proper evaluation for LPS and I-FABP as markers for the risk of inflammatory non-AIDS co-morbidities. These insights are instrumental for orienting clinical investigations in PLWH.

Micronutrients, Metabolic Complications, and Inflammation in Ugandan Children With HIV.

Selenium, zinc, and chromium are essential micronutrients. Their alterations have been associated with HIV disease progression, metabolic complications, and mortality. This is a cross-sectional study in children with perinatally acquired HIV (PHIV, n = 57), HIV-exposed uninfected (HEU, n = 59), and HIV-unexposed uninfected (HIV-, n = 56) children aged 2 to 10 years old, age- and sex-matched, enrolled in Uganda. PHIV were on stable antiretroviral therapy (ART) with undetectable viral load. We measured plasma concentrations of selenium, zinc, and chromium as well as markers of systemic inflammation, monocyte activation, and gut integrity. Among PHIV children, 93% had viral load ≤20 copies/mL, median CD4 was 37%, and 77% were receiving a nonnucleotide reserve transcriptase regimen. Median age of all participants was 8 years and 55% were girls. Median selenium concentrations were higher in PHIV compared with the HEU and HIV groups (P < 0.001), 46% of children overall had low zinc status (P = 0.18 between groups). Higher selenium, but not chromium or zinc, was associated with lower IL6, sTNFRI and II, and higher beta d glucan, a marker of fungal translocation, zonulin, a marker of gut permeability, oxidized LDL and insulin resistance (P ≤ 0.01). In this cohort of PHIV on ART in Uganda, there is a high prevalence of low zinc status overall. Higher plasma selenium concentrations were associated with lower systemic inflammation and higher gut integrity markers. Although our findings do not support the use of micronutrient supplementation broadly for PHIV in Uganda, further studies are warranted to assess the role of selenium supplements in attenuating heightened inflammation.

Virulence assessment of six major pathogenic Candida species in the mouse model of invasive candidiasis caused by fungal translocation

Gastrointestinal colonization has been considered as the primary source of candidaemia; however, few established mouse models are available that mimic this infection route. We therefore developed a reproducible mouse model of invasive candidiasis initiated by fungal translocation and compared the virulence of six major pathogenic Candida species. The mice were fed a low-protein diet and then inoculated intragastrically with Candida cells. Oral antibiotics and cyclophosphamide were then administered to facilitate colonization and subsequent dissemination of Candida cells. Mice infected with Candida albicans and Candida tropicalis exhibited higher mortality than mice infected with the other four species. Among the less virulent species, stool titres of Candida glabrata and Candida parapsilosis were higher than those of Candida krusei and Candida guilliermondii. The fungal burdens of C. parapsilosis and C. krusei in the livers and kidneys were significantly greater than those of C. guilliermondii. Histopathologically, C. albicans demonstrated the highest pathogenicity to invade into gut mucosa and liver tissues causing marked necrosis. Overall, this model allowed analysis of the virulence traits of Candida strains in individual mice including colonization in the gut, penetration into intestinal mucosa, invasion into blood vessels, and the subsequent dissemination leading to lethal infections.

High-resolution mycobiota analysis reveals dynamic intestinal translocation preceding invasive candidiasis.

The intestinal microbiota is a complex community of bacteria, archaea, viruses, protists and fungi1,2. While the composition of bacterial constituents has been linked to immune homeostasis and to infectious susceptibility3–7, the role of non-bacterial constituents and of cross-kingdom microbial interactions in these processes is poorly understood2,8. Fungi represent a major cause of infectious morbidity and mortality in immune-compromised individuals, though the relationship of intestinal fungi (i.e., the mycobiota) with fungal bloodstream infections (BSI) remains undefined9. We integrated an optimized bioinformatics pipeline with high-resolution mycobiota sequencing and comparative genomic analyses of fecal and blood specimens from recipients of allogeneic hematopoietic cell transplant (allo-HCT). Patients with Candida BSI experienced a prior marked intestinal expansion of pathogenic Candida species; this expansion consisted of a complex dynamic between multiple species and subspecies with a stochastic translocation pattern into the bloodstream. The intestinal expansion of pathogenic Candida species was associated with a significant loss in bacterial burden and diversity, particularly in the anaerobes. Thus, simultaneous analysis of intestinal fungi and bacteria identifies dysbiosis states across kingdoms that may promote fungal translocation and facilitate invasive disease. These findings support microbiota-driven approaches to identify patients at risk for fungal BSI for pre-emptive therapeutic intervention.

Changes in the Fungal Marker β-D-Glucan After Antiretroviral Therapy and Association With Adiposity.

BackgroundBacterial translocation in HIV is associated with inflammation and metabolic complications; few data exist on the role of fungal translocation.MethodsA5260s was a substudy of A5257, a prospective open label randomized trial in which treatment-naïve people with HIV (PWH) were randomized to tenofovir-emtricitabine (TDF/FTC) plus atazanavir-ritonavir (ATV/r), darunavir-ritonavir (DRV/r), or raltegravir (RAL) over 96 weeks. Baseline was assessed, and changes in β-D-glucan (BDG) were assessed at weeks 4, 24, and 96. Wilcoxon rank-sum tests were used to compare distribution shifts in the changes from baseline between treatment arms and linear regression models to assess associations between BDG and measures of inflammation, body composition, and insulin resistance.ResultsTwo hundred thirty-one participants were randomized; 90% were male, the median age was 36 years, HIV-1 RNA was 4.56 log10c/mL, and CD4 cell count was 338 cells/mm3. There was an overall increase in BDG over 96 weeks (1.57 mean fold-change; 95% confidence interval, 1.39 to 1.77) with no differences between arms. Twofold higher BDG levels at week 96 were associated with increases in trunk fat (8%) and total fat (7%) over 96 weeks (P ≤ .035). At week 4, BDG correlated with I-FABP, a marker of enterocyte damage, and zonulin, a marker of intestinal permeability (r = .19–.20; P < .01).ConclusionsIn treatment-naïve participants initiating antiretroviral therapy (ART) with TDF/FTC and either RAL or ATV/r, DRV/r, BDG, a marker of fungal translocation, increased similarly in all arms over 96 weeks. This may represent continued intestinal damage during ART and resulting fungal translocation. Higher BDG was associated with larger fat gains on ART.