Nocardia infections in solid organ and hematopoietic stem cell transplant recipients

Purpose of review Nocardia spp. is a gram-positive bacteria that may cause infections in humans. Nocardiosis has been described since the early years of transplantation. This review aims to provide an overview of present knowledge regarding posttransplant nocardiosis, with a focus on recent findings. Recent findings Nocardiosis is not rare among transplant recipients, especially after thoracic transplantation and/or in case of intense immunosuppressive regimen or use of tacrolimus. Low-dose cotrimoxazole is not effective to prevent nocardiosis. Although lung is the most common site of infection, more than 40% of organ transplant patients have a disseminated infection. As central nervous system involvement is frequent (about 1/3 of the patients) and possibly asymptomatic, brain imaging is mandatory. Diagnosis relies on direct examination and culture; molecular species identification is useful to guide treatment. Although cotrimoxazole is the drug for which we have the strongest clinical experience, other antibiotics such as linezolid, parenteral cephalosporins, carbapenems, and amikacin can be used to treat nocardiosis. Although treatment duration has historically been set to at least 6 months, shorter durations (<120 days) seem associated with a good outcome in selected patients. Summary Physicians in charge of transplant patients should be aware of nocardiosis. Diagnosis and management of transplant recipients with nocardiosis require a multidisciplinary approach.SCOPUS: re.jinfo:eu-repo/semantics/publishe

Severe Dermatophytosis and Acquired or Innate Immunodeficiency: A Review

Dermatophytes are keratinophilic fungi responsible for benign and common forms of infection worldwide. However, they can lead to rare and severe diseases in immunocompromised patients. Severe forms include extensive and/or invasive dermatophytosis, i.e., deep dermatophytosis and Majocchi’s granuloma. They are reported in immunocompromised hosts with primary (autosomal recessive CARD9 deficiency) or acquired (solid organ transplantation, autoimmune diseases requiring immunosuppressive treatments, HIV infection) immunodeficiencies. The clinical manifestations of the infection are not specific. Lymph node and organ involvement may also occur. Diagnosis requires both mycological and histological findings. There is no consensus on treatment. Systemic antifungal agents such as terbinafine and azoles (itraconazole or posaconazole) are effective. However, long-term outcome and treatment management depend on the site and extent of the infection and the nature of the underlying immunodeficiency

Catalytic conversion of methane over a biomass char for hydrogenproduction: deactivation and regeneration by steam gasification

International audienceCH4 decomposition over a wood char was investigated as an alternative green catalyst to produce hydrogen from hydrocarbons. Pyrolytic carbon (pyrocarbon) deposition leads to apparent deactivation of the catalyst by pore-mouth plugging. The activity of the carbon bed and its available surface area are easily restored by H2O gasification. The used char with pyrocarbon deposition was even found to be more reactive to gasification than the fresh char used in our conditions. This finding was highlighted by: (i)determination of gasification reaction extents by steam, (ii) temperature-programmed oxidation (TPO) of the fresh, used and reactivated chars and (iii) TPO under differential scanning calorimetry of these chars and demineralised chars. High-resolution transmission electron microscope (HRTEM) analysis of the chars showed different multiscale organisation of the carbon materials (disordered and graphitic mesoporous nanostructures). The fast regeneration of the used char could be attributed to the catalytic effect of the minerals present in the char that are reduced under our conditions of CH4 conversion. The predominant oxidation of the pyrocarbon compared to the char during its regeneration is evidenced through differential annealing (at 1800◦C) followed by XRD analysis. The oxidation of pyrocarbon is faster than the oxidation of the weakly reactive mesoporous carbon in char as shown by the HRTEManalysis. Consequently, wood char is an effective, easy to regenerate and cheap catalyst for convertinghydrocarbons (CH4 or tar) into syngas

Thermal behaviour of chlorine in nuclear graphite at a microscopic scale

International audienceIn this paper, we present the study of thermal behaviour of 36Cl in nuclear graphite used in the St. Laurent A2 UNGG reactor (graphite moderated and CO2 cooled reactor). 37Cl, used to simulate 36Cl displaced from its original structural site by recoil, has been implanted into nuclear graphite samples (energy = 250 keV, fluence = 5 × 1013 at cm-2). The samples have been annealed in the 200-800 °C temperature range and analysed by SIMS. Structural modifications have been controlled by Raman microspectroscopy. This study shows that, in the considered temperature range and for a short annealing duration (4 h), chlorine is released almost athermally. At 500 °C, around 20% of the initial 37Cl content is released. At 800 °C, the release reaches a plateau and the loss of 37Cl is around 30%. Raman microspectroscopy shows that 37Cl implantation induces a structural disorder and that during annealing, the original structure is not completely recovered. © 2009 Elsevier B.V. All rights reserved

Why are so many cases of invasive aspergillosis missed?

International audienceInvasive aspergillosis (IA) incidence is increasing in several countries like France, and numerous cases are indeed missed and still only diagnosed at autopsy as evidenced by recently published data. Such missed diagnoses are obviously encountered when appropriate diagnostic tools are not available especially in low resource areas or when biologists have not been trained enough in medical mycology (i.e., microscopic examination and culture in most of those areas). Besides logistical issues, which are indeed critical, IA may not be recognized because clinicians failed to consider that risk factors are evolving with the IA burden now observed among patients with chronic lymphoid malignancies or receiving new bio-therapies, with diabetes mellitus or liver cirrhosis and/or acute alcoholic hepatitis, with patients from the intensive care unit (ICU) and among patients with some predisposing primary immune deficiencies now reaching the adult's age. This is also the case for human immunodeficiency virus (HIV)-infected patients who failed to meet the classical definitions of IA. From the radiology perspective, new entities of IA have also emerged which absolutely need to be recognized especially bronchial-based-IA among allogeneic stem cell transplant recipients. Finally, from the laboratory side, contribution and limits of indirect blood biomark-ers should be integrated to the clinical life in order not to miss IA cases. To conclude, several diagnostic tools should be combined and a constant dialog between laboratory and clinics is crucial to appropriately diagnose IA

COVID-19 outbreak in vaccinated patients from a haemodialysis unit: antibody titres as a marker of protection from infection

International audienceBackground Patients on maintenance haemodialysis (HD) have an increased risk of severe coronavirus disease 2019 (COVID-19) and a reduced response to vaccines. Data are needed to identify immune correlates of protection in this population. Methods Following a COVID-19 outbreak among vaccinated patients in a HD unit, clinical data and serological response to BNT162b2 vaccine were retrospectively recorded. Results Among 53 patients present in the dialysis room, 14 were infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) alpha variant (COVID_Pos) and 39 were not. Compared with uninfected patients, COVID_Pos patients more frequently had additional causes of immunosuppression (50% versus 21%; P = .046) and were more often scheduled on the Monday–Wednesday–Friday (MWF) shift (86% versus 39%; P = .002). Moreover, COVID_Pos had lower anti-spike (S) immunoglobulin G (IgG) titres than uninfected patients {median 24 BAU/mL [interquartile range (IQR) 3–1163] versus 435 [99–2555]; P = .001} and lower neutralization titres [median 108 (IQR 17–224) versus 2483 (481–43 908); P = .007]. Anti-S and neutralization antibody titres are correlated (r = 0.92, P &lt; .001). In multivariable analysis, an MWF schedule {odds ratio [OR] 10.74 [95% confidence interval (CI) 1.9–93.5], P = .014} and anti-S IgG titres 1 month before the outbreak [&lt;205 BAU/mL: OR 0.046 (95% CI 0.002–0.29), P = .006] were independently associated with COVID-19 infection. None of the patients with anti-S IgG &gt;284 BAU/mL got infected. Ten of 14 COVID_Pos patients were treated with casirivimab and imdevimab. No patient developed severe disease. Conclusions Anti-S IgG titre measured prior to exposure correlates to protection from SARS-CoV-2 infection in HD patients. BNT162b2 vaccination alone or in combination with monoclonal antibodies prevented severe COVID-19

Case Report: Immune Checkpoint Blockade Plus Interferon-Γ Add-On Antifungal Therapy in the Treatment of Refractory Covid-Associated Pulmonary Aspergillosis and Cerebral Mucormycosis

Invasive fungal diseases (IFD) still cause substantial morbidity and mortality, and new therapeutic approaches are urgently needed. Recent data suggest a benefit of checkpoint inhibitors (ICI). We report the case of a diabetic patient with refractory IFD following a SARSCoV-2 infection treated by ICI and interferon-gamma associated with antifungal treatment