Invasive Aspergillosis In Immunocompromised Patients Research Articles

Increased Risk of Invasive Aspergillosis in Immunocompromised Patients With Persistent SARS-CoV-2 Viral Shedding >8 Weeks, Retrospective Case-control Study.

Immunocompromised patients now represent the population most at risk for severe coronavirus disease 2019. Persistent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral shedding was reported in these patients ranging from several weeks up to 9 months. We conducted a bicentric retrospective case-control study to identify risk and prognostic factors associated with persistent viral shedding in immunocompromised patients. Symptomatic immunocompromised adults with persistent SARS-CoV-2 viral shedding >8 weeks were retrospectively included between 1 March 2020 and 24 April 2022 at 2 university hospitals in Paris, France, and matched with a control group consisting of symptomatic immunocompromised patients without persistent viral shedding. Twenty-nine immunocompromised patients with persistent viral shedding were compared with 40 controls. In multivariate analysis, fever and lymphocytopenia (<0.5 G/L) were associated with an increased risk of persistent viral shedding (odds ratio [OR]: 3.3; 95% confidence interval [CI], 1.01-11.09) P = .048 and OR: 4.3; 95% CI, 1.2-14.7; P = .019, respectively). Unvaccinated patients had a 6-fold increased risk of persistent viral shedding (OR, 6.6; 95% CI, 1.7-25.1; P = .006). Patients with persistent viral shedding were at risk of hospitalization (OR: 4.8; 95 CI, 1.5-15.6; P = .008), invasive aspergillosis (OR: 10.17; 95 CI, 1.15-89.8; P = .037) and death (log-rank test <0.01). Vaccine coverage was protective against SARS-CoV-2 persistent viral shedding in immunocompromised patients. This new group of immunocompromised patients with SARS-CoV-2 persistent viral shedding is at risk of developing invasive aspergillosis and death and should therefore be systematically screened for this fungal infection for as long as the viral shedding persists.

An Overview of Systematic Reviews of Polymerase Chain Reaction (PCR) for the Diagnosis of Invasive Aspergillosis in Immunocompromised People: A Report of the Fungal PCR Initiative (FPCRI)-An ISHAM Working Group.

This overview of reviews (i.e., an umbrella review) is designed to reappraise the validity of systematic reviews (SRs) and meta-analyses related to the performance of Aspergillus PCR tests for the diagnosis of invasive aspergillosis in immunocompromised patients. The methodological quality of the SRs was assessed using the AMSTAR-2 checklist; the quality of the evidence (QOE) within each SR was appraised following the GRADE approach. Eight out of 12 SRs were evaluated for qualitative and quantitative assessment. Five SRs evaluated Aspergillus PCR on bronchoalveolar lavage fluid (BAL) and three on blood specimens. The eight SRs included 167 overlapping reports (59 evaluating PCR in blood specimens, and 108 in BAL), based on 107 individual primary studies (98 trials with a cohort design, and 19 with a case-control design). In BAL specimens, the mean sensitivity and specificity ranged from 0.57 to 0.91, and from 0.92 to 0.97, respectively (QOE: very low to low). In blood specimens (whole blood or serum), the mean sensitivity ranged from 0.57 to 0.84, and the mean specificity from 0.58 to 0.95 (QOE: low to moderate). Across studies, only a low proportion of AMSTAR-2 critical domains were unmet (1.8%), demonstrating a high quality of methodological assessment. Conclusions. Based on the overall methodological assessment of the reviews included, on average we can have high confidence in the quality of results generated by the SRs.

Fungal Zinc Homeostasis and Its Potential as an Antifungal Target: A Focus on the Human Pathogen Aspergillus fumigatus.

Aspergillus fumigatus is an opportunistic airborne fungus that causes severe invasive aspergillosis in immunocompromised patients. Zinc is an essential micronutrient for the growth of A. fumigatus and even for all microorganisms. An increasing number of studies have reported that fungal zinc acquisition ability plays a key role in fungal survival in hosts with an extremely zinc-limited microenvironment. The ability to fight scarcity and excess of zinc are tightly related to fungal virulence and may be used as new potential targets. Because the regulation of zinc homeostasis is important, a thorough understanding of the functional genes involved in the regulatory network for zinc homeostasis is required for fungal pathogens. The current mini-review summarized potential zinc homeostasis regulators in A. fumigatus and classified these regulators according to localization and function, which were identified or predicted based on A. fumigatus or deduced from homologs in model yeasts. Future perspectives for zinc homeostasis regulators as potential antifungal targets to treat invasive aspergillosis are also discussed.

Role of biomarkers in the diagnosis of invasive aspergillosis in immunocompromised patients

BackgroundInvasive aspergillosis is one of the important causes of infection in immunocompromised patients. This study aimed to evaluate the roles of biomarkers in the diagnosis of invasive aspergillosis and their relationship with antifungal stewardship programs.Methods190 sera from 52 immunocompromised patients and volunteer individuals were included in this study. 18 immunocompromised volunteers without IA and 34 patients with probable and proven aspergillosis according to the European Organization for Research and Treatment of Cancer and the Mycoses Study Group consensus definitions were entered in this study. The respective sera were evaluated for procalcitonin, soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) levels; white blood cells count (WBC) count, C reactive protein (CRP), lactate dehydrogenase (LDH), and erythrocyte sedimentation rate (ESR) values. Demographic data and clinical characteristics of patients were extracted from their files.ResultsThe male-to-female ratio and mean age of patients were 22/12 and 38.9 years, respectively. The hematologic disorder was the most predisposing factor (29/34, 85.3%). Sensitivity of biomarkers for diagnosis of invasive aspergillosis was 70.6% (cut off value > 190 pg/mL for sTREM-1, 71% (cut off value > 260 pg/mL) for PCT, 85.3% (cut off value > 193 U/L) for LDH, 94.1% (cut off value > 8 mg/l) for CRP, 64.7% (cut off value < 5200 cells/ml) for WBC, and 85.3% (cut off value > 23 mm/h) for ESR. Twelve patients died, with significantly increased sTREM-1 levels and decreased WBC count in them.ConclusionAccording to our data, evaluation of the biomarkers can help in the diagnosis, management, and prediction of the severity of Aspergillus infection, and the rational use of antifungal agents in immunocompromised patients.

Life-Threatening Sinonasal Invasive Aspergillosis Easily Misdiagnosed

Background and Objectives Invasive fungal sinusitis is extremely rare. Yet the consequences of this infection may be fatal if not diagnosed correctly at an early stage. We discuss three cases of Aspergillosis sphenoid sinusitis that were misdiagnosed and have led to fatal consequences.Subjects and Method This is a retrospective analysis of cases diagnosed as invasive fungal sinusitis of sphenoid sinus.Results All three cases were of men who had immunocompromised medical histories that included leukemia and diabetes mellitus. The patients presented symptoms that included fever, chronic headache, weakness on one side, and facial edema. In the first case, CT showed no suspicious lesions that indicated fungal infection. However, five days after being prescribed antibiotics, the patient suffered obstruction of the right internal carotid artery (ICA) and right cavernous sinus. In the second case, CT showed total obstruction in the left ICA and a soft tissue mass in the left sphenoid sinus that extended and involved the left cavernous sinus. In the last case, CT showed soft density progression in the right sphenoid sinus with bone erosion when compared to images taken eight days earlier. In each of these cases, we performed emergency endoscopic sinus surgery. One case was confirmed to be invasive aspergillosis by histology whereas the other two cases were suspected to be invasive aspergillosis based on their past medical histories, clinical findings and image studies.Conclusion Clinicians must take great care to rule out invasive aspergillosis in immunocompromised patients with sinusitis.

Phosphomannose Isomerase Is Involved in Development, Stress Responses, and Pathogenicity of Aspergillus flavus.

ABSTRACTAspergillus flavus causes invasive aspergillosis in immunocompromised patients and severe contamination of agriculturally important crops by producing aflatoxins. The fungal cell wall is absent in animals and is structurally different from that of plants, which makes it a potential antifungal drug target due to its essentiality for fungal survival. Mannose is one of the important components in the fungal cell wall, which requires GDP-mannose (GDP-Man) as the primary donor. Three consecutive enzymes, namely, phosphomannose isomerase (PMI), phosphomannose mutase (PMM), and GDP-mannose phosphorylase (GMPP), are required for GDP-Man biosynthesis. Thus, PMI is of prime importance in cell wall biosynthesis and also has an active role in sugar metabolism. Here, we investigated the functional role of PMI in A. flavus by generating a pmiA-deficient strain. The mutant required exogenous mannose to survive and exhibited reduced growth rate, impaired conidiation, early germination, disturbance in stress responses, and defects in colonization of crop seeds. Furthermore, attenuated virulence of the mutant was documented in both Caenorhabditis elegans and Galleria mellonella infection models. Our results suggested that PMI plays an important role in the development, stress responses, and pathogenicity of A. flavus and therefore could serve as a potential target for battling against infection and controlling aflatoxin contamination caused by A. flavus.IMPORTANCE Aspergillus flavus is a common fungal pathogen of humans, animals, and agriculturally important crops. It causes invasive aspergillosis in humans and also produces highly carcinogenic mycotoxins in postharvest crops that threaten food safety worldwide. To alleviate or eliminate the threats posed by A. flavus, it is necessary to identify genes involved in pathogenicity and mycotoxin contamination. However, little progress has been made in this regard. Here, we focused on PMI, which is the first enzyme involved in the biosynthesis pathway of GDP-Man and thus is important for cell wall synthesis and protein glycosylation. Our study revealed that PMI is important for growth of A. flavus. It is also involved in conidiation, germination, morphogenesis, stress responses, and pathogenicity of A. flavus. Thus, PMI is a potent antifungal target to curb the threats posed by A. flavus.

Phosphoglucose Isomerase Plays a Key Role in Sugar Homeostasis, Stress Response, and Pathogenicity in Aspergillus flavus

Aspergillus flavus is one of the important human and plant pathogens causing not only invasive aspergillosis in immunocompromised patients but also crop contamination resulting from carcinogenic aflatoxins (AFs). Investigation of the targeting factors that are involved in pathogenicity is of unmet need to dismiss the hazard. Phosphoglucose isomerase (PGI) catalyzes the reversible conversion between glucose-6-phosphate and fructose-6-phosphate, thus acting as a key node for glycolysis, pentose phosphate pathway, and cell wall biosynthesis in fungi. In this study, we constructed an A. flavus pgi deletion mutant, which exhibited specific carbon requirement for survival, reduced conidiation, and slowed germination even under optimal experimental conditions. The Δpgi mutant lost the ability to form sclerotium and displayed hypersusceptibility to osmotic, oxidative, and temperature stresses. Furthermore, significant attenuated virulence of the Δpgi mutant was documented in the Caenorhabditis elegans infection model, Galleria mellonella larval model, and crop seeds. Our results indicate that PGI in A. flavus is a key enzyme in maintaining sugar homeostasis, stress response, and pathogenicity of A. flavus. Therefore, PGI is a potential target for controlling infection and AF contamination caused by A. flavus.

Genetic Interactions Between Aspergillus fumigatus Basic Leucine Zipper (bZIP) Transcription Factors AtfA, AtfB, AtfC, and AtfD.

Aspergillus fumigatus is an opportunistic fungus, capable of causing Invasive Aspergillosis in immunocompromised patients, recently transplanted or undergoing chemotherapy. In the present work, we continued the investigation on A. fumigatus AtfA-D transcription factors (TFs) characterizing possible genetic and physical interactions between them after normal growth and stressing conditions. We constructed double null mutants for all the possible combinations of ΔatfA-, -B, -C, and -D, and look into their susceptibility to different stressing conditions. Our results indicate complex genetic interactions among these TFs that could impact the response to different kinds of stressful conditions. AtfA-D interactions also affect the A. fumigatus virulence in Galleria mellonella. AtfA:GFP is ~97% located in the nucleus while about 20-30% of AtfB, -C, and -D:GFP locate into the nucleus in the absence of any stress. Under stressing conditions, AtfB, -C, and -D:GFP translocate to the nucleus about 60-80% upon the addition of sorbitol or H2O2. These four TFs are also interacting physically forming all the possible combinations of heterodimers. We also identified that AtfA-D physically interact with the MAPK SakA in the absence of any stress and upon osmotic and cell wall stresses. They are involved in the accumulation of trehalose, glycogen and metabolic assimilation of different carbon sources.

Using Expanded Natural Killer Cells as Therapy for Invasive Aspergillosis.

Invasive aspergillosis (IA) is a major opportunistic fungal infection in patients with haematological malignancies. Morbidity and mortality rates are high despite anti-fungal treatment, as the compromised status of immune system prevents the host from responding optimally to conventional therapy. This raises the consideration for immunotherapy as an adjunctive treatment. In this study, we evaluated the utility of expanded human NK cells as treatment against Aspergillus fumigatus infection in vitro and in vivo. The NK cells were expanded and activated by K562 cells genetically modified to express 4-1BB ligand and membrane-bound interleukin-15 (K562-41BBL-mbIL-15) as feeders. The efficacy of these cells was investigated in A. fumigatus killing assays in vitro and as adoptive cellular therapy in vivo. The expanded NK cells possessed potent killing activity at low effector-to-target ratio of 2:1. Fungicidal activity was morphotypal-dependent and most efficacious against A. fumigatus conidia. Fungicidal activity was mediated by dectin-1 receptors on the expanded NK cells leading to augmented release of perforin, resulting in enhanced direct cytolysis. In an immunocompromised mice pulmonary aspergillosis model, we showed that NK cell treatment significantly reduced fungal burden, hence demonstrating the translational potential of expanded NK cells as adjunctive therapy against IA in immunocompromised patients.

Performance evaluation of a new mobile air-treatment technology at-rest and under normal work conditions in a conventional hematology room

Invasive fungal infections incidence in patients with hematological malignancies is increasing. Air treatment remains an essential preventive measure. Guidelines state that high-risk patients should be housed in units equipped with High-Efficiency Particulate Air filtration. Mobile air-treatment devices may be considered as alternatives or as a complement to the ventilation system. We assessed the decontamination performances of a new mobile air-treatment device in a conventional hematology room. This device connected or not to a plenum combining Ultra-Low Particulate Air filtration and non-thermal catalysis process has been evaluated with or without healthcare activities (one sampling at-rest and triplicate samplings in activity). Environmental particulate, airborne and surface fungal and total mesophilic flora (TMF) samplings were performed with a total of 1800 min of particles counting, 144 air and 240 surface samplings. At-rest, both devices achieved a 2-log decrease of airborne particles, ISO 4 being the maximal particle class reached under the plenum. Whatever the healthcare activities and the location in the room, ISO 7 was the maximal particle class reached. TMF and fungal air contamination were lower during healthcare activities when the air portable cleaners were running. The bed was the area the least contaminated in the room. No differences were observed for surface contamination. This work provides arguments of the efficacy of a new mobile air-treatment device to decrease particle counts and airborne bioburden in real-life conditions. Studies have yet to be conducted to document the impact of these devices on the risk of invasive aspergillosis in immunocompromised patients.

Prophylaxis and Treatment of Invasive Aspergillosis: Who and How of Prophylaxis, Treatment, and New Therapies

To discuss the approach to antifungal prophylaxis and treatment for invasive aspergillosis in immunocompromised patients with hematologic malignancies, hematopoietic stem cell transplant, and solid organ transplant recipients. Primary prophylaxis against Aspergillus is recommended for patients with acute myelogenous leukemia receiving remission-induction chemotherapy. Posaconazole or voriconazole are appropriate antifungal agents. A new formulation of itraconazole (SUBA-itraconazole) is an alternative option. Breakthrough infections on isavuconazole prophylaxis have been recently reported. For liver transplant recipients, targeted prophylaxis is recommended in the presence of certain risk factors. Voriconazole and isavuconazole are the preferred agents for the treatment of invasive aspergillosis. Isavuconazole, a novel extended-spectrum triazole with activity against Aspergillus and Mucorales, was found to be non-inferior compared to voriconazole. Combination of voriconazole with an echinocandin is generally not recommended. Reduction in immunosuppression is recommended as part of the management of invasive aspergillosis. The adjunctive use of interferon-γ may be considered in patients with severe or refractory disease, although a benefit has not been clearly demonstrated. The approach to prevention and treatment of invasive aspergillosis has evolved along with changes in immunosuppressive treatment and introduction of novel antifungal agents.

Galactomannan detection in broncho-alveolar lavage fluid for invasive aspergillosis in immunocompromised patients.

Invasive aspergillosis (IA) is a life-threatening opportunistic mycosis that occurs in some people with a compromised immune system. The serum galactomannan enzyme-linked immunosorbent assay (ELISA) rapidly gained widespread acceptance as part of the diagnostic work-up of a patient suspected of IA. Due to its non-invasive nature, it can be used as a routine screening test. The ELISA can also be performed on bronchoalveolar lavage (BAL), allowing sampling of the immediate vicinity of the infection. The invasive nature of acquiring BAL, however, changes the role of the galactomannan test significantly, for example by precluding its use as a routine screening test. To assess the diagnostic accuracy of galactomannan detection in BAL for the diagnosis of IA in people who are immunocompromised, at different cut-off values for test positivity, in accordance with the Cochrane Diagnostic Test Accuracy Handbook. We searched three bibliographic databases including MEDLINE on 9 September 2016 for aspergillosis and galactomannan as text words and subject headings where appropriate. We checked reference lists of included studies for additional studies. We included cohort studies that examined the accuracy of BAL galactomannan for the diagnosis of IA in immunocompromised patients if they used the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) classification as reference standard. Two review authors assessed study quality and extracted data. Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used for quality assessment. We included 17 studies in our review. All studies except one had a high risk of bias in two or more domains. The diagnostic performance of an optical density index (ODI) of 0.5 as cut-off value was reported in 12 studies (with 1123 patients). The estimated sensitivity was 0.88 (95% confidence interval (CI) 0.75 to 1.00) and specificity 0.81 (95% CI 0.71 to 0.91). The performance of an ODI of 1.0 as cut-off value could be determined in 11 studies (with 648 patients). The sensitivity was 0.78 (95% CI 0.61 to 0.95) and specificity 0.93 (95% CI 0.87 to 0.98). At a cut-off ODI of 1.5 or higher, the heterogeneity in specificity decreased significantly and was invariably >90%. The optimal cut-off value depends on the local incidence and clinical pathway. At a prevalence of 12% a hypothetical population of 1000 patients will consist of 120 patients with IA. At a cut-off value of 0.5 14 patients with IA will be missed and there will be 167 patients incorrectly diagnosed with IA. If we use the test at a cut-off value of 1.0, we will miss 26 patients with IA. And there will be 62 patients incorrectly diagnosed with invasive aspergillosis. The populations and results were very heterogeneous. Therefore, interpretation and extrapolation of these results has to be performed with caution. A test result of 1.5 ODI or higher appears a strong indicator of IA.

Iron: an essential nutrient for Aspergillus fumigatus and a fulcrum for pathogenesis.

Aspergillus fumigatus is a ubiquitous saprophytic fungus that can cause life-threatening invasive aspergillosis in immunocompromised patients. Apart from the immune status of the host only a few characterized virulence factors have been identified. In this review, we describe the role of iron in the manifestation of A. fumigatus virulence. We gathered recent clinical evidence suggesting that tissue iron overload increases the risk of invasive aspergillosis occurrence. Furthermore, we summarize the mechanisms that A. fumigatus employs to achieve iron homeostasis and their importance in A. fumigatus proliferation in vitro. We describe two recent in-vivo models that clearly demonstrate the importance of iron in A. fumigatus growth and invasion. Based on these recent findings, therapy aimed at managing A. fumigatus iron homeostasis locally could make conditions more favorable to the host.

Human NK cells adapt their immune response towards increasing multiplicities of infection of Aspergillus fumigatus

BackgroundThe saprophytic fungus Aspergillus fumigatus reproduces by generation of conidia, which are spread by airflow throughout nature. Since humans are inhaling certain amounts of spores every day, the (innate) immune system is constantly challenged. Even though macrophages and neutrophils carry the main burden, also NK cells are regarded to contribute to the antifungal immune response. While NK cells reveal a low frequency, expression and release of immunomodulatory molecules seem to be a natural way of their involvement.ResultsIn this study we show, that NK cells secrete chemokines such as CCL3/MIP-1α, CCL4/MIP-1β and CCL5/RANTES early on after stimulation with Aspergillus fumigatus and, in addition, adjust the concentration of chemokines released to the multiplicity of infection of Aspergillus fumigatus.ConclusionsThese results further corroborate the relevance of NK cells within the antifungal immune response, which is regarded to be more and more important in the development and outcome of invasive aspergillosis in immunocompromised patients after hematopoietic stem cell transplantation. Additionally, the correlation between the multiplicity of infection and the expression and release of chemokines shown here may be useful in further studies for the quantification and/or surveillance of the NK cell involvement in antifungal immune responses.

Microbe Profile: Aspergillus fumigatus: a saprotrophic and opportunistic fungal pathogen.

Aspergillus fumigatus is a saprotrophic fungus that continuously disseminates spores (conidia) into the environment. It is also the most common and opportunistic aerial fungal pathogen, causing allergic and chronic lung pathologies including the fatal invasive aspergillosis in immunocompromised patients. The pathobiology of aspergillosis is complex and depends on the competence of the host immune system. Moreover, A. fumigatus has become a model to study unique features of fungi. This includes the fungal cell wall, which not only acts as a rigid skeleton for protection against hostile environments but also plays significant roles during infection by manipulating the host immune response.

Evaluation of Hirst-type spore traps in outdoor Aspergillaceae monitoring during large demolition work in hospital.

Demolition can generate fungal spore suspensions in association with various adverse health effects, such as high risk of invasive aspergillosis in immunocompromised patients. One block of Edouard Herriot Hospital was entirely demolished. The aim of the present study was to evaluate Hirst-type spore traps utility in monitoring outdoor Aspergillaceae (Aspergillus spp. + Penicillium spp.) spores in part of Edouard Herriot Hospital (Lyon, France) undergoing major demolition. Three periods were scheduled in 2015: (A) Gutting of building and asbestos removal, (B) Demolition of floors, (C) Excavation and earthwork. Outdoor Aspergillaceae fungal load was monitored by cultivable (Air Ideal®, bioMérieux) and non-cultivable methods (Lanzoni VPPS-2000, Analyzair®, Bologna, Italy). Differences of Aspergillaceae recorded with Hirst-type spore traps were observed between Gerland and Edouard Herriot Hospital. Differences between Aspergillaceae were recorded between day time and night time at Gerland and Edouard Herriot Hospital. Daily paired differences between Aspergillaceae recorded with non-cultivable methodology at Edouard Herriot Hospital and in an area without demolition work were significant in Period A vs Period B (p = 10–4) and Period A vs Period C (p = 10–4). Weak correlation of daily Aspergillaceae recorded by both methods at Edouard Herriot Hospital was significant only for Period C (r = 0.26, p = 0.048, n = 58). Meteorological parameters and type of demolition works were found to heavily influenced Aspergillaceae dispersion. Non-cultivable methodology is a promising tool for outdoor Aspergillaceae scrutiny during major demolition work in hospital, helping infection control staff to rapidly implement control measures.

Aspergillus galactomannan detection in exhaled breath condensate compared to bronchoalveolar lavage fluid for the diagnosis of invasive aspergillosis in immunocompromised patients

ObjectivesExhaled breath condensate (EBC) is a noninvasive means of sampling the airways that has shown significant promise in the diagnosis of many disorders. There have been no reports of its usefulness in the detection of galactomannan (GM), a component of the cell wall of Aspergillus. The suitability of EBC for the detection of GM for the diagnosis of invasive aspergillosis (IA) using the Platelia Aspergillus enzyme-linked immunosorbent assay was investigated. MethodsProspective, cross-sectional study of lung transplant recipient and haemotologic malignancy patients at a university centre. EBC samples were compared to concomitant bronchoalveolar lavage (BAL) samples among lung transplant recipients and healthy controls. EBC was collected over 10 minutes using a refrigerated condenser according to the European Respiratory Society/American Thoracic Society recommendations, with the BAL performed immediately thereafter. ResultsA total of 476 EBC specimens with 444 matched BAL specimens collected from lung transplant recipients (n = 197) or haemotologic malignancy patients (n = 133) were examined. Both diluted and untreated EBC optical density (OD) values (0.0830, interquartile range (IQR) 0.0680–0.1040; and 0.1130, IQR 0.0940–0.1383), respectively, from all patients regardless of clinical syndrome were significantly higher than OD values in healthy control EBCs (0.0508, IQR 0.0597–0.0652; p < 0.0001). However, the OD index values did not correlate with the diagnosis of IA (44 samples were associated with IA). Furthermore, no significant correlation was found between EBC GM and the matched BAL specimen. ConclusionsGM is detectable in EBC; however, no correlation between OD index values and IA was noted in lung transplant recipients.

Persistence within dendritic cells marks an antifungal evasion and dissemination strategy of Aspergillus terreus

Aspergillus terreus is an airborne human fungal pathogen causing life-threatening invasive aspergillosis in immunocompromised patients. In contrast to Aspergillus fumigatus, A. terreus infections are associated with high dissemination rates and poor response to antifungal treatment. Here, we compared the interaction of conidia from both fungal species with MUTZ-3-derived dendritic cells (DCs). After phagocytosis, A. fumigatus conidia rapidly escaped from DCs, whereas A. terreus conidia remained persisting with long-term survival. Escape from DCs was independent from DHN-melanin, as A. terreus conidia expressing wA showed no increased intracellular germination. Within DCs A. terreus conidia were protected from antifungals, whereas A. fumigatus conidia were efficiently cleared. Furthermore, while A. fumigatus conidia triggered expression of DC activation markers such as CD80, CD83, CD54, MHCII and CCR7, persistent A. terreus conidia were significantly less immunogenic. Moreover, DCs confronted with A. terreus conidia neither produced pro-inflammatory nor T-cell stimulating cytokines. However, TNF-α addition resulted in activation of DCs and provoked the expression of migration markers without inactivating intracellular A. terreus conidia. Therefore, persistence within DCs and possibly within other immune cells might contribute to the low response of A. terreus infections to antifungal treatment and could be responsible for its high dissemination rates.

Evidence of unique genetic diversity in Aspergillus fumigatus isolates from Cameroon.

Aspergillus fumigatus is a saprophytic fungus that can cause lethal invasive aspergillosis in immunocompromised patients. Recent studies have shown that Eurasian and North American populations of A.fumigatus often consist of genetically diverse strains. However, very little is known about African populations of A.fumigatus. Here, we characterise the genetic diversity and triazole susceptibility of A.fumigatus in Cameroon, West Africa. A total of 495 soil samples were obtained from nine collection sites in three Cameroonian regions. Nine microsatellite markers were used to genotype all 51 identified A.fumigatus isolates. In vitro susceptibility to itraconazole and voriconazole was tested using micro broth dilution. The 51 Cameroonian A.fumigatus isolates belonged to 45 genotypes. Consistent with recombination, 32 of 36 possible pairwise loci combinations are phylogenetically incompatible. Interestingly, evidence for geographic sub-structuring was found within Cameroon and the sub-population with the most evidence of recombination was also the least susceptible sub-population to the triazole antifungals tested. Furthermore, the Cameroonian sample was significantly differentiated from those in Eurasia and North America. Overall, our results indicate the genetic uniqueness of Cameroonian A.fumigatus populations and that additional novel genetic diversity likely exist in other parts of Africa.

Galactomannan detection in broncho-alveolar lavage fluid for invasive aspergillosis in immunocompromised patients

Galactomannan detection in broncho-alveolar lavage fluid for invasive aspergillosis in immunocompromised patients