Multicenter evaluation of the Toxoplasma gondii Real-TM (Sacace) kit performance for the molecular diagnosis of toxoplasmosis.

The molecular detection of Toxoplasma gondii DNA is a key tool for the diagnosis of disseminated and congenital toxoplasmosis. This multicentric study from the Molecular Biology Pole of the French National Reference Center for toxoplasmosis aimed to evaluate Toxoplasma gondii Real-TM PCR kit (Sacace). The study compared the analytical and clinical performances of this PCR assay with the reference PCRs used in proficient laboratories. PCR efficiencies varied from 90% to 112%; linearity zone extended over four log units (R2 > 0.99) and limit of detection varied from 0.01 to ≤1 Tg/mL depending on the center. Determined on 173 cryopreserved DNAs from a large range of clinical specimens, clinical sensitivity was 100% [106/106; 95 confidence interval (CI): 96.5%-100%] and specificity was 100% (67/67; 95 CI: 94.6%-100%). The study revealed two potential limitations of the Sacace PCR assay: the first was the inconsistency of the internal control (IC) when added to the PCR mixture. This point was not found under routine conditions when the IC was added during the extraction step. The second is a lack of practicality, as the mixture is distributed over several vials, requiring numerous pipetting operations. Overall, this study provides useful information for the molecular diagnosis of toxoplasmosis; the analytical and clinical performances of the Sacace PCR kit were satisfactory, the kit having sensitivity and specificity similar to those of expert center methods and being able to detect low parasite loads, at levels where multiplicative analysis gives inconsistently positive results. Finally, the study recommends multiplicative analysis in particular for amniotic fluids, aqueous humor, and other single specimens.

Atovaquone exposure and Pneumocystis jirovecii cytochrome b mutations: French data and review of the literature.

Pneumocystis jirovecii is a transmissible fungus responsible for severe pneumonia (Pneumocystis pneumonia [PCP]) in immunocompromised patients. Missense mutations due to atovaquone selective pressure have been identified on cytochrome b (CYB) gene of P. jirovecii. It was recently shown that atovaquone prophylaxis can lead to the selection of specific P. jirovecii CYB mutants potentially resistant to atovaquone among organ transplant recipients. In this context, our objectives were to provide data on P. jirovecii CYB mutants and the putative selective pressure exerted by atovaquone on P. jirovecii organisms in France. A total of 123 patients (124 P. jirovecii specimens) from four metropolitan hospitals and two overseas hospitals were retrospectively enrolled. Fourteen patients had prior exposure to atovaquone, whereas 109 patients did not at the time of P. jirovecii detection. A 638 base-pair fragment of the CYB gene of P. jirovecii was amplified and sequenced. A total of 10 single nucleotide polymorphisms (SNPs) were identified. Both missense mutations C431T (Ala144Val) and C823T (Leu275Phe), located at the Qo active site of the enzyme, were significantly associated with prior atovaquone exposure, these mutations being conversely incidental in the absence of prior atovaquone exposure (P < 0.001). Considering that the aforementioned hospitals may be representative of the national territory, these findings suggest that the overall presence of P. jirovecii CYB mutants remains low in France.

The mutations C431T (Ala144Val) and C823T (Leu275Phe) at the cytochrome b (CYB) active site of Pneumocystis jirovecii are associated with patient prior exposure to atovaquone. Conversely, these mutations are incidental in the absence of exposure. Overall, the presence of P. jirovecii CYB mutants remains low in France.

Evaluation of two commercial kits and two laboratory-developed qPCR assays compared to LAMP for molecular diagnosis of malaria.

BACKGROUND: Malaria is an infectious disease considered as one of the biggest causes of mortality in endemic areas. This life-threatening disease needs to be quickly diagnosed and treated. The standard diagnostic tools recommended by the World Health Organization are thick blood smears microscopy and immuno-chromatographic rapid diagnostic tests. However, these methods lack sensitivity especially in cases of low parasitaemia and non-falciparum infections. Therefore, the need for more accurate and reliable diagnostic tools, such as real-time polymerase chain reaction based methods which have proven greater sensitivity particularly in the screening of malaria, is prominent. This study was conducted at the French National Malaria Reference Centre to assess sensitivity and specificity of two commercial malaria qPCR kits and two in-house developed qPCRs compared to LAMP. METHODS: 183 blood samples received for expertise at the FNMRC were included in this study and were subjected to four different qPCR methods: the Biosynex Ampliquick® Malaria test, the BioEvolution Plasmodium Typage test, the in-house HRM and the in-house TaqMan qPCRs. The specificity and sensitivity of each method and their confidence intervals were determined with the LAMP-based assay Alethia® Malaria as the reference for malaria diagnosis. The accuracy of species diagnosis of the Ampliquick® Malaria test and the two in-house qPCRs was also evaluated using the BioEvolution Plasmodium Typage test as the reference method for species identification. RESULTS: The main results showed that when compared to LAMP, a test with excellent diagnostic performances, the two in-house developed qPCRs were the most sensitive (sensitivity at 100% for the in-house TaqMan qPCR and 98.1% for the in-house HRM qPCR), followed by the two commercial kits: the Biosynex Ampliquick® Malaria test (sensitivity at 97.2%) and the BioEvolution Plasmodium Typage (sensitivity at 95.4%). Additionally, with the in-house qPCRs we were able to confirm a Plasmodium falciparum infection in microscopically negative samples that were not detected by commercial qPCR kits. This demonstrates that the var genes of P. falciparum used in these in-house qPCRs are more reliable targets than the 18S sRNA commonly used in most of the developed qPCR methods for malaria diagnosis. CONCLUSION: Overall, these results accentuate the role molecular methods could play in the screening of malaria. This may represent a helpful tool for other laboratories looking to implement molecular diagnosis methods in their routine analysis, which could be essential for the detection and treatment of malaria carriers and even for the eradication of this disease.

Comprehensive Analysis of Transcript and Protein Relative Abundance During Blood Stages of Plasmodium falciparum Infection.

Plasmodium falciparum is the main causative agent of human malaria. During the intraerythrocytic development cycle, the P. falciparum morphology changes dramatically from circulating young rings to sequestered mature trophozoites and schizonts. Sequestered forms contribute to the pathophysiology of severe malaria as the infected erythrocytes obstruct the microvascular flow in deep organs and induce local inflammation. However, the sequestration mechanism limits the access to the corresponding parasitic form in the clinical samples from patients infected with P. falciparum. To complement this deficiency, we aimed to evaluate the relevance of mRNA study as a proxy of protein expression in sequestered parasites. To do so, we conducted a proteotranscriptomic analysis using five independent P. falciparum laboratory strain samples. RNA sequencing was performed, and the mRNA expression level was assessed on circulating ring-stage parasites. The level of protein expression were measured by LC-MS/MS on the corresponding sequestered mature forms after 18-24 h of maturation. Overall, our results showed a strong transcriptome/transcriptome and a very strong proteome/proteome correlation between samples. Moreover, positive correlations of mRNA and protein expression levels were found between ring-stage transcriptomes and mature form proteomes. However, twice more transcripts were identified at the ring stage than proteins at the mature trophozoite stage. A high level of transcript expression did not guarantee the detection of the corresponding protein. Finally, we pointed out discrepancies at the individual gene level. Taken together, our results show that transcript and protein expressions are overall correlated. However, mRNA abundance is not a perfect proxy of protein expression at the individual level. Importantly, our study shows limitations of the "blind" use of RNA-seq and the importance of multiomics approaches for P. falciparum blood stage study in clinical samples.

Intravenous Artesunate for the Treatment of Severe Imported Malaria: Implementation, Efficacy, and Safety in 1391 Patients.

BACKGROUND: Intravenous artesunate is the World Health Organization-recommended first-line treatment for severe malaria worldwide, but it is still not fully licensed in Europe. Observational studies documenting its safety and efficacy in imported malaria are thus essential. METHODS: We prospectively collected clinical and epidemiological features of 1391 artesunate-treated patients among 110 participant centers during the first 7 years (2011-2017) of a national program implemented by the French Drug Agency. RESULTS: Artesunate became the most frequent treatment for severe malaria in France, rising from 9.9% in 2011 to 71.4% in 2017. Mortality was estimated at 4.1%. Treatment failure was recorded in 27 patients, but mutations in the Kelch-13 gene were not observed. Main reported adverse events (AEs) were anemia (136 cases), cardiac events (24, including 20 episodes of conduction disorders and/or arrhythmia), and liver enzyme elevation (23). Mortality and AEs were similar in the general population and in people with human immunodeficiency virus, who were overweight, or were pregnant, but the only pregnant woman treated in the first trimester experimented a hemorrhagic miscarriage. The incidence of post-artesunate-delayed hemolysis (PADH) was 42.8% when specifically assessed in a 98-patient subgroup, but was not associated with fatal outcomes or sequelae. PADH was twice as frequent in patients of European compared with African origin. CONCLUSIONS: Artesunate was rapidly deployed and displayed a robust clinical benefit in patients with severe imported malaria, despite a high frequency of mild to moderate PADH. Further explorations in the context of importation should assess outcomes during the first trimester of pregnancy and collect rare but potentially severe cardiac AEs.

Plasmodium ovale wallikeri and P. ovale curtisi Infections and Diagnostic Approaches to Imported Malaria, France, 2013-2018.

We retrospectively analyzed epidemiologic, clinical, and biologic characteristics of 368 Plasmodium ovale wallikeri and 309 P. ovale curtisi infections treated in France during January 2013­December 2018. P. ovale wallikeri infections displayed deeper thrombocytopenia and shorter latency periods. Despite similar clinical manifestations, P. ovale wallikeri­infected patients were more frequently treated with artemisinin-based combination therapy. Although the difference was not statistically significant, P. ovale wallikeri­infected patients were 5 times more frequently hospitalized in intensive care or intermediate care and had a higher proportion of severe thrombocytopenia than P. ovale curtisi­infected patients. Rapid diagnostic tests that detect aldolase were more efficient than those detecting Plasmodium lactate dehydrogenase. Sequence analysis of the potra gene from 90 P. ovale isolates reveals an insufficient polymorphism for relapse typing.

Microsporidiosis after liver transplantation: A French nationwide retrospective study.

BACKGROUND: Microsporidiosis has been largely reported in patients with acquired immunodeficiency syndrome, but emerged as a cause of persistent diarrhea in solid organ transplant patients. METHODS: Through the French Microsporidiosis Network and the Groupe français de recherche en greffe de foie, we collected all microsporidiosis cases identified in liver transplant patients between 1995 and 2020 in France. RESULTS: We identified 24 liver transplant recipients with microsporidiosis. Sex ratio was balanced and median age was 58.8 (3.5-83.5) years (there were 4 children). Microsporidiosis occurred at a median time of 3.9 (0.1-18.9) years post-transplant. Median duration of diarrhea before diagnosis was 22 days (12-45). Therapeutic care included immunosuppressive therapy changes in 20 patients, as follows: stop cyclosporine or tacrolimus (n = 2), dose reduction of cyclosporine or tacrolimus (n = 12), stop MMF (n = 5), and dose reduction of corticosteroids (n = 1). In addition, 15 patients received specific therapy against microsporidiosis: fumagillin (n = 11) or albendazole (n = 4). Median duration of treatment was 14 days (8-45 days). Finally, 7 patients had immunosuppressive treatment tapering only. Microsporidiosis was complicated by renal failure in 15 patients, requiring dialysis in one case. Two patients had infection relapse. No patient presented proven rejection within the 3 months after microsporidiosis. None of the patients died within the 3 months after microsporidiosis. CONCLUSIONS: Microsporidiosis is a very rare infection after liver transplantation but can induce severe dehydration and renal failure. Therefore, it must be systematically sought in any case of persistent diarrhea after first line screening of frequent infectious causes.

Aspergillus flavus malignant external otitis in a diabetic patient: case report and literature review.

PURPOSE: Malignant external otitis is an aggressive and potentially life-threatening infection. This rare disorder is typically caused by Pseudomonas aeruginosa and affects almost exclusively elderly diabetic patients. However, fungal malignant external otitis have been identified, especially in immunocompromised hosts. METHODS: We report a rare case of invasive malignant external otitis caused by Aspergillus flavus in a diabetic patient without other underlying immunosuppression. A review of Aspergillus spp. malignant external otitis since voriconazole became the first line for invasive aspergillosis was performed. RESULTS: A 72-year-old man with diabetes mellitus developed invasive malignant external otitis with a vascular involvement. The patient was treated with empiric courses of antibiotics until a fungal infection was diagnosed. Proven Apsergillus infection was based on histopathological examination and isolation of A. flavus from culture of osteo-meningeal biopsies. Despite optimal antimicrobial therapy with voriconazole, the patient presented with cerebral infarction in the setting of an angioinvasive fungal infection leading to a fatal outcome. From a review of the literature, we found 39 previously published cases of proven Aspergillus spp. malignant external otitis treated with new triazoles. CONCLUSION: Given our experience and the literature review, a fungal etiology should be considered early in the course of malignant external otitis unresponsive to a conventional broad spectrum antibiotic therapy, with the need for a tissue biopsy to confirm the diagnosis.

Evaluation of PCR To Monitor Plasmodium falciparum Treatment Efficacy in a Nonendemicity Setting.

Adequate clinical and parasitological response (ACPR) after malaria treatment remains challenging to assess in settings of malaria nonendemicity. Biological evaluation of parasitological clearance relies on microscopic investigation of thick blood smears, which is a specific technique that not all diagnosis laboratories are able to perform. Rapid diagnosis tests (RDTs) and molecular biology techniques are proposed as alternatives to microscope conventional techniques; however, their performance for treatment efficacy evaluation is controversial. We present here a retrospective comparative study for RDT and PCR (nested and high-resolution-melting quantitative PCR [HRM-qPCR]) evaluation of ACPR in a nonendemicity context. Blood samples from 133 patients presenting a Plasmodium falciparum monoinfection were included. Samples obtained at the time of diagnosis and at 3, 7, and 28 days after diagnosis were investigated. Histidine-rich protein 2 (HRP-2)-based RDT results remained positive in 51% of cases 28 days after diagnosis and appropriate therapeutic management. Parasite DNA was detected by the two PCR techniques (nested PCR and HRM-qPCR) in 12% and 10% of samples 28 days after treatment initiation, respectively. No therapeutic failure was recorded in the studied patients. Persistence of positive signal might reflect the presence of circulating asexual parasites or persistence of HRP-2 and parasitic DNA in patient's peripheral blood after parasitic clearance.

Disseminated toxoplasmosis associated with hemophagocytic syndrome after kidney transplantation: A case report and review.

Disseminated toxoplasmosis is infrequent after kidney transplant transmission but life-threatening because of a lack of diagnostic suspicion as well as specific chemoprophylaxis recommendations. Solid organ transplantation has resulted in few cases of disseminated toxoplasmosis presenting with associated hemophagocytic syndrome. Herein, we report, within the context of a donor/receiver mismatch, a case of a toxoplasmosis associated with hemophagocytic syndrome in a kidney transplant recipient. Molecular and serological investigations confirmed Toxoplasma gondii transmission through the kidney graft.

Pneumocystis Cytochrome b Mutants Associated With Atovaquone Prophylaxis Failure as the Cause of Pneumocystis Infection Outbreak Among Heart Transplant Recipients.

Background: Although trimethoprim-sulfamethoxazole is the more efficient drug for prophylactic and curative treatment of pneumocystosis, atovaquone is considered a second-line prophylactic treatment in immunocompromised patients. Variations in atovaquone absorption and mutant fungi selection after atovaquone exposure have been associated with atovaquone prophylactic failure. We report here a Pneumocystis jirovecii cytochrome b (cyt b) mutation (A144V) associated with such prophylactic failure during a pneumocystosis outbreak among heart transplant recipients. Methods: Analyses of clinical data, serum drug dosage, and molecular modeling of the P. jirovecii Rieske-cyt b complex were performed to investigate these prophylactic failures. Results: The cyt b A144V mutation was detected in all infected, heart transplant recipient patients exposed to atovaquone prophylaxis but in none of 11 other immunocompromised, infected control patients not treated with atovaquone. Serum atovaquone concentrations associated with these prophylactic failures were similar than those found in noninfected exposed control patients under a similar prophylactic regimen. Computational modeling of the P. jirovecii Rieske-cyt b complex and in silico mutagenesis indicated that the cyt b A144V mutation might alter the volume of the atovaquone-binding pocket, which could decrease atovaquone binding. Conclusions: These data suggest that the cyt b A144V mutation confers diminished sensitivity to atovaquone, resulting in spread of Pneumocystis pneumonia among heart transplant recipients submitted to atovaquone prophylaxis. Potential selection and interhuman transmission of resistant P. jirovecii strain during atovaquone prophylactic treatment has to be considered and could limit its extended large-scale use in immucompromised patients.

Outbreak of Pneumocystis jirovecii Infection Among Heart Transplant Recipients: Molecular Investigation and Management of an Interhuman Transmission.

Background: An outbreak of Pneumocystis jirovecii pneumonia (PCP) occurred among heart transplant recipients (HTR) at the outpatient clinic of a university hospital, from March to September 2015. Clinical, therapeutic, biological, and molecular data were analyzed to determine its origin and control the outbreak. Methods: Clinical and biological data regarding all HTR followed in the outpatient clinic were collected. PCP diagnosis was based on microscopy and real-time polymerase chain reaction (PCR). Investigations were performed by building a transmission map, completed by genotyping Pneumocystis isolates and by a control of chemoprophylaxis observance. Asymptomatic exposed patients were screened for colonization using real-time PCR. Results: Among 124 HTR, 7 PCP cases were confirmed. Screening identified 3 additional patients colonized by P. jirovecii. All patients were cured, and no further cases were identified after trimethoprim-sulfamethoxazole prophylaxis was introduced in the entire cohort. Genotyping demonstrated the same strain in all PCP cases and colonized patients. All cases were linked with possible transmission chains from 2 possible index patients. Interhuman transmission was significantly associated with more frequent visits in the outpatient clinic. Six cases were receiving atovaquone as a prophylaxis. The occurrence of PCP was significantly associated with atovaquone prophylaxis. Conclusions: This is the first outbreak with detailed molecular analysis in HTR so far. Genotyping and transmission chain confirmed interhuman transmission in all colonized/infected PCP cases. Outpatient clinic layout and high encounters probably caused this PCP cluster, which was controlled after systematic trimethoprim-sulfamethoxazole prophylaxis in exposed patients.

Autochthonous Case of Eosinophilic Meningitis Caused by Angiostrongylus cantonensis, France, 2016.

We report a case of a 54-year-old Moroccan woman living in France diagnosed with eosinophilic meningitis caused by Angiostrongylus cantonensis. Diagnosis was based on clinical symptoms and confirmed by testing of serum and cerebrospinal fluid samples. Physicians should consider the risk for A. cantonensis infection outside of endemic areas.

Infected erythrocytes and plasma proteomics reveal a specific protein signature of severe malaria.

Cerebral malaria (CM), the most lethal complication of Plasmodium falciparum severe malaria (SM), remains fatal for 15-25% of affected children despite the availability of treatment. P. falciparum infects and multiplies in erythrocytes, contributing to anemia, parasite sequestration, and inflammation. An unbiased proteomic assessment of infected erythrocytes and plasma samples from 24 Beninese children was performed to study the complex mechanisms underlying CM. A significant down-regulation of proteins from the ubiquitin-proteasome pathway and an up-regulation of the erythroid precursor marker transferrin receptor protein 1 (TFRC) were associated with infected erythrocytes from CM patients. At the plasma level, the samples clustered according to clinical presentation. Significantly, increased levels of the 20S proteasome components were associated with SM. Targeted quantification assays confirmed these findings on a larger cohort (n = 340). These findings suggest that parasites causing CM preferentially infect reticulocytes or erythroblasts and alter their maturation. Importantly, the host plasma proteome serves as a specific signature of SM and presents a remarkable opportunity for developing innovative diagnostic and prognostic biomarkers.

Primary musculoskeletal hydatid cyst of the thigh: Diagnostic and curative challenge for an unusual localization.

Primary muscular echinococcosis is an uncommon localization of hydatid cysts. The nonspecific clinical presentation and possible post-therapeutic complications lead to problems for the diagnosis of this infection and the support of the patient. The authors describe an unusual case of double hydatid cyst of the vastus intermedius muscle. After a precise preoperative evaluation based on clinical, radiological and biological examinations, a surgical excision by pericystectomy combined with perioperative chemotherapy enabled the authors to treat the patient and to prevent postoperative complications. The diagnostic tools and the treatment of this particular type of echinococcosis are discussed.

L'échinococcose musculaire primaire est un foyer inhabituel des kystes hydatiques. La présentation clinique non spécifique et les complications post-thérapeutiques éventuelles peuvent s'associer à des difficultés à diagnostiquer cette infection et à soutenir le patient. Les auteurs décrivent un cas inhabituel de double kyste hydatique du muscle vaste intermédiaire. Après une évaluation préopératoire détaillée fondée sur des examens clinique, radiologique et biologique, les auteurs ont traité le patient en procédant à une excision chirurgicale par périkystectomie conjuguée à une chimiothérapie périopératoire, ce qui a permis d'éviter les complications postopératoires. Ils présentent également les outils diagnostiques et le traitement de ce type d'échinococcose.

Faecal Viral Excretion and Gastrointestinal Co-Infection Do Not Explain Digestive Presentation in COVID-19 Patients.

The physiopathological mechanisms responsible for digestive symptoms in COVID-19 patients are still unclear. The aim of this study was to determine the influence of faecal viral shedding on digestive symptoms and propose differential diagnoses in order to understand the gastrointestinal clinical spectrum in acute cases of COVID-19. All patients managed between March and May 2020, from whom stool samples were collected for microbiological investigations, were included. Microbiological analysis consisted of syndromic PCR screening and microscopic parasitological examination supplemented with microsporidia and multiplex protozoa PCR. SARS-CoV-2 infection was diagnosed via viral detection in respiratory and frozen stool samples, completed via serological test when necessary. Epidemiological, clinical, radiological, and biological data and clinical courses were compared according to COVID-19 status and faecal SARS-CoV-2 shedding and enteric co-infection status. The sample included 50 COVID+ and 67 COVID- patients. Faecal viral shedding was detected in 50% of stool samples and was associated with a higher viral load in the upper respiratory tract. Detected enteric pathogens were not different between subjects with different COVID-19 statuses or faecal SARS-CoV-2 shedding and had no impact on the clinical course for COVID-19 patients. The connection between SARS-CoV-2 shedding and enteric pathogen co-infection involvement in gastrointestinal presentation and clinical course is still unclear, suggesting other processes are involved in digestive disorders in COVID-19 patients.

Revealing invisible cell phenotypes with conditional generative modeling.

Biological sciences, drug discovery and medicine rely heavily on cell phenotype perturbation and microscope observation. However, most cellular phenotypic changes are subtle and thus hidden from us by natural cell variability: two cells in the same condition already look different. In this study, we show that conditional generative models can be used to transform an image of cells from any one condition to another, thus canceling cell variability. We visually and quantitatively validate that the principle of synthetic cell perturbation works on discernible cases. We then illustrate its effectiveness in displaying otherwise invisible cell phenotypes triggered by blood cells under parasite infection, or by the presence of a disease-causing pathological mutation in differentiated neurons derived from iPSCs, or by low concentration drug treatments. The proposed approach, easy to use and robust, opens the door to more accessible discovery of biological and disease biomarkers.

Evaluation of the Bio-Evolution Microsporidia generic and typing real-time PCR assays for the diagnosis of intestinal microsporidiosis.

Cases of intestinal microsporidiosis infection are underestimated and affect both immunocompromized and immunocompetent patients. Real-time PCR is superseding microscopic examination for its diagnosis in medical analysis laboratories. However, few manufacturers include microsporidia in their PCR panel for the diagnosis of infectious gastroenteritis. Here, we evaluated the performances of the real-time PCR assays microsporidia generic and microsporidia typing (Bio-Evolution, France) on the Rotor-Gene Q real-time PCR cycler (Qiagen, France). We included 45 negative and 44 positive stool samples for Enterocytozoon bieneusi (n = 34, with various genotypes), Encephalitozoon intestinalis (n = 4), Encephalitozoon hellem (n = 4), and Encephalitozoon cuniculi (n = 2). We also studied a four-year survey of an inter-laboratory quality control program including 9 centers that used this commercial assay. Sensitivity and specificity of the microsporidia generic assay were 86.4% and 93.3%, respectively. Encephalitozoon hellem and Encephalitozoon cuniculi were detected by the microsporidia generic PCR assay but not by the microsporidia typing PCR assay. These results were consistent with the results of the inter-laboratory quality control program. In conclusion, Bio-Evolution Real-time PCR assays are useful tools for intestinal microsporidiosis, but negative results for microsporidia typing assays require supplementary analyses to confirm E. hellem or E. cuniculi infections.

Title: Évaluation des tests de PCR en temps réel Bio-Evolution Microsporidia generic et typing pour le diagnostic de la microsporidiose intestinale. Abstract: Les microsporidioses intestinales sont des infections sous-estimées affectant à la fois les patients immunodéprimés et immunocompétents. Le diagnostic microscopique en laboratoire médical est aujourd'hui supplanté par la PCR en temps réel. Cependant, peu de fabricants incluent les microsporidies dans leurs panels PCR pour le diagnostic des gastro-entérites infectieuses. Ici, nous avons évalué les performances des tests PCR en temps réel microsporidia generic et microsporidia typing (Bio-Evolution, France) sur le thermocycleur PCR en temps réel Rotor-Gene Q (Qiagen, France). Nous avons inclus 45 échantillons de selles négatifs et 44 échantillons positifs pour Enterocytozoon bieneusi (n = 34, avec divers génotypes), Encephalitozoon intestinalis (n = 4), Encephalitozoon hellem (n = 4) et Encephalitozoon cuniculi (n = 2). Nous avons également analysé les résultats sur 4 ans d'un programme de contrôle qualité inter-laboratoires dont 9 centres ont utilisé ces kits commerciaux. La sensibilité et la spécificité du kit microsporidia generic étaient respectivement de 86,4 % et 93,3 %. Encephalitozoon hellem et E. cuniculi ont été détectés par le kit microsporidia generic mais pas par le kit microsporidia typing. Ces résultats étaient cohérents avec ceux du programme de contrôle de qualité inter-laboratoires. En conclusion, les tests de PCR en temps réel Bio-Evolution sont des outils intéressants pour la microsporidiose intestinale, mais un résultat négatif pour le test de typage microsporidia nécessite une analyse supplémentaire pour confirmer les infections à E. hellem ou E. cuniculi.

Altered Subpopulations of Red Blood Cells and Post-treatment Anemia in Malaria.

In acute malaria, the bulk of erythrocyte loss occurs after therapy, with a nadir of hemoglobin generally observed 3-7 days after treatment. The fine mechanisms leading to this early post-treatment anemia are still elusive. We explored pathological changes in RBC subpopulations by quantifying biochemical and mechanical alterations during severe malaria treated with artemisinin derivatives, a drug family that induce "pitting" in the spleen. In this study, the hemoglobin concentration dropped by 1.93 G/dl during therapy. During the same period, iRBC accounting for 6.12% of all RBC before therapy (BT) were replaced by pitted-RBC, accounting for 5.33% of RBC after therapy (AT). RBC loss was thus of 15.9%, of which only a minor part was due to the loss of iRBC or pitted-RBC. When comparing RBC BT and AT to normal controls, lipidomics revealed an increase in the cholesterol/phosphatidylethanolamine ratio (0.17 versus 0.24, p < 0.001) and cholesterol/phosphatidylinositol ratio (0.36 versus 0.67, p = 0.001). Using ektacytometry, we observed a reduced deformability of circulating RBC, similar BT and AT, compared to health control donors. The mean Elongation Index at 1.69Pa was 0.24 BT and 0.23 AT vs. 0.28 in controls (p < 0.0001). At 30Pa EI was 0.56 BT and 0.56 AT vs. 0.60 in controls (p < 0.001). The retention rate (rr) of RBC subpopulations in spleen-mimetic microsphere layers was higher for iRBC (rr = 20% p = 0.0033) and pitted-RBC (rr = 19%, p = 0.0031) than for healthy RBC (0.12%). Somewhat surprisingly, the post-treatment anemia in malaria results from the elimination of RBC that were never infected.