Multiple pathways for glucose phosphate transport and utilization support growth of Cryptosporidium parvum

Cryptosporidium parvum is an obligate intracellular parasite with a highly reduced mitochondrion that lacks the tricarboxylic acid cycle and the ability to generate ATP, making the parasite reliant on glycolysis. Genetic ablation experiments demonstrated that neither of the two putative glucose transporters CpGT1 and CpGT2 were essential for growth. Surprisingly, hexokinase was also dispensable for parasite growth while the downstream enzyme aldolase was required, suggesting the parasite has an alternative way of obtaining phosphorylated hexose. Complementation studies in E. coli support a role for direct transport of glucose-6-phosphate from the host cell by the parasite transporters CpGT1 and CpGT2, thus bypassing a requirement for hexokinase. Additionally, the parasite obtains phosphorylated glucose from amylopectin stores that are released by the action of the essential enzyme glycogen phosphorylase. Collectively, these findings reveal that C. parvum relies on multiple pathways to obtain phosphorylated glucose both for glycolysis and to restore carbohydrate reserves

Cryptosporidium infection of human small intestinal epithelial cells induces type III interferon and impairs infectivity of Rotavirus

Cryptosporidiosis is a major cause of severe diarrheal disease in infants from resource poor settings. The majority of infections are caused by the human-specific pathoge

Cestode infections in non-human primates suggest the existence of zoonotic cycles in the area surrounding the Strasbourg primatology center

Background: Several cases of infections due to Echinococcus multilocularis, Taenia martis and Taenia crassiceps were recently described in various species of captive non-human primates (NHPs) harbored in the Strasbourg Primate Center (SPC). Furthermore, one of the first cases of human cysticercosis due to T. martis was described in the Strasbourg region. These data suggest the existence of zoonotic cycles of tapeworm infections in the direct environment of the SPC. The aim of our study was to assess the prevalence of larval cestode infections among intermediate and definitive hosts in the close neighborhood of the center. We analyzed carnivore mammal fecal samples as well as rodent carcasses, collected inside or near the SPC, using PCR. Furthermore, we performed serology for Echinococcus spp. and Taenia spp. on NHP sera. Results: We found that 14.5% (95% CI [8.6; 20.4]) of 138 carnivore feces were positive for E. multilocularis-DNA, as well as 25% (95% CI [5.5; 57.2]) of 12 rodent carcasses, and 5.1% (95% CI [1.4; 8.7]) for T. martis or T. crassiceps. Of all NHPs tested, 10.1% (95% CI [3.8; 16.4]) were seropositive for Echinococcus spp. and 8.2% (95% CI [1.3; 15.1]) for Taenia spp. Conclusions: Our data support the existence of zoonotic cycles of larval cestode infections in the direct environment of the primatology center affecting NHPs harbored in the SPC, potentially threatening the human population living in this area. Since this zoonotic risk is borne by local wildlife, and given the severity of these infections, it seems necessary to put in place measures to protect captive NHPs, and further studies to better assess the risk to human populations

Une nouvelle approche de l’immunité innée lors de la toxoplasmose oculaire : le rôle méconnu des interférons de type I et III

Ocular toxoplasmosis (TO) is an inflammatory condition of the eye caused by infection with the protozoan parasite Toxoplasma gondii. The aim of this study was to explore the role of interferon-β (type I) and IFNs-λ (type III) during TO. Using in vitro models of human retinal cultures, we studied the expression of different cytokines, parasitic proliferation and permeability of retinal epithelium cell monolayers (RPEC) in response to stimulation by type I & III IFNs and infection. We show that most of the cells tested are reactive to stimulation by type I and type III IFNs, that infection with T. gondii induces the expression of type I and type III IFNs, that stimulation of RPEC by type I IFNs limits parasitic proliferation during the infection of these cells by T. gondii and that the IFNs-λ prevent the disjunction of the RPEC following infection by T. gondii.La toxoplasmose oculaire (TO) est une affection inflammatoire de l’œil consécutive à l’infection par le parasite protozoaire Toxoplasma gondii. L’objectif de cette étude était d’explorer le rôle de l’interféron-β (type I) et des IFNs-λ (type III) au cours de la TO. À l’aide de modèles in vitro de cultures rétiniennes humaines nous avons étudié l’expression de différentes cytokines, la prolifération parasitaire et la perméabilité de monocouches de cellules d’épithélium rétinien (RPEC) en réponse à la stimulation par des IFNs de type I et III et à l’infection. Nous montrons que la plupart des cellules testées sont réactives à la stimulation par des IFNs de type I et de type III, que l’infection par T. gondii induit l’expression d’IFNs de type I et de type III, que la stimulation de RPEC par des IFNs de type I limite la prolifération parasitaire lors de l’infection de ces cellules par T. gondii et que les IFNs-λ préviennent la disjonction des RPEC consécutive à l’infection par T. gondii

A new approach to innate immunity during ocular toxoplasmosis : the little-known role of type I and III interferons

La toxoplasmose oculaire (TO) est une affection inflammatoire de l’œil consécutive à l’infection par le parasite protozoaire Toxoplasma gondii. L’objectif de cette étude était d’explorer le rôle de l’interféron-β (type I) et des IFNs-λ (type III) au cours de la TO. À l’aide de modèles in vitro de cultures rétiniennes humaines nous avons étudié l’expression de différentes cytokines, la prolifération parasitaire et la perméabilité de monocouches de cellules d’épithélium rétinien (RPEC) en réponse à la stimulation par des IFNs de type I et III et à l’infection. Nous montrons que la plupart des cellules testées sont réactives à la stimulation par des IFNs de type I et de type III, que l’infection par T. gondii induit l’expression d’IFNs de type I et de type III, que la stimulation de RPEC par des IFNs de type I limite la prolifération parasitaire lors de l’infection de ces cellules par T. gondii et que les IFNs-λ préviennent la disjonction des RPEC consécutive à l’infection par T. gondii.Ocular toxoplasmosis (TO) is an inflammatory condition of the eye caused by infection with the protozoan parasite Toxoplasma gondii. The aim of this study was to explore the role of interferon-β (type I) and IFNs-λ (type III) during TO. Using in vitro models of human retinal cultures, we studied the expression of different cytokines, parasitic proliferation and permeability of retinal epithelium cell monolayers (RPEC) in response to stimulation by type I & III IFNs and infection. We show that most of the cells tested are reactive to stimulation by type I and type III IFNs, that infection with T. gondii induces the expression of type I and type III IFNs, that stimulation of RPEC by type I IFNs limits parasitic proliferation during the infection of these cells by T. gondii and that the IFNs-λ prevent the disjunction of the RPEC following infection by T. gondii

Pathophysiology of ocular toxoplasmosis: Facts and open questions.

Infections with the protozoan parasite Toxoplasma gondii are frequent, but one of its main consequences, ocular toxoplasmosis (OT), remains poorly understood. While its clinical description has recently attracted more attention and publications, the underlying pathophysiological mechanisms are only sparsely elucidated, which is partly due to the inherent difficulties to establish relevant animal models. Furthermore, the particularities of the ocular environment explain why the abundant knowledge on systemic toxoplasmosis cannot be just transferred to the ocular situation. However, studies undertaken in mouse models have revealed a central role of interferon gamma (IFNγ) and, more surprisingly, interleukin 17 (IL17), in ocular pathology and parasite control. These studies also show the importance of the genetic background of the infective Toxoplasma strain. Indeed, infections due to exotic strains show a completely different pathophysiology, which translates in a different clinical outcome. These elements should lead to more individualized therapy. Furthermore, the recent advance in understanding the immune response during OT paved the way to new research leads, involving immune pathways poorly studied in this particular setting, such as type I and type III interferons. In any case, deeper knowledge of the mechanisms of this pathology is needed to establish new, more targeted treatment schemes

Intestinal microsporidiosis in Strasbourg from 2014 to 2016: emergence of an Enterocytozoon bieneusi genotype of Asian origin

International audienceMicrosporidia cause opportunistic infections in highly immunodeficient individuals. Few studies on the epidemiology of these infections have been conducted in France. Between 2014 and 2016, we undertook a study to estimate the prevalence and circulating genotypes of this fungus-related microorganism among the population of Strasbourg University Hospital. Samples were collected from hospitalized patients and analyzed using microscopy and molecular assays. Strains from positive subjects were sequenced for genotyping. Only 7/661 patients (1.1%) were positive for microsporidia, and the only species identified was Enterocytozoon bieneusi. Two patients presented immunodeficiency linked to AIDS, and five transplant recipients presented immunodeficiency linked to immunosuppressive therapies. Only five patients received specific antimicrosporidial treatment, but clinical outcomes were good in all cases. We identified four genotypes: A and D in patients with AIDS, and C and S9 in transplant recipients. To date, genotype S9 has been described only once. This genotype is similar to those found in farm animals in China. Because some of these animals have been introduced to Central Europe, we postulate that this genotype might be of Asian origin. Thus, genotyping microsporidial strains may be of epidemiological and clinical interest to identify potential outbreak sources depending on the infecting strains

Cestode infections in non-human primates suggest the existence of zoonotic cycles in the area surrounding the Strasbourg primatology center

International audienceBackground: Several cases of infections due to Echinococcus multilocularis, Taenia martis and Taenia crassiceps were recently described in various species of captive non-human primates (NHPs) harbored in the Strasbourg Primate Center (SPC). Furthermore, one of the first cases of human cysticercosis due to T. martis was described in the Strasbourg region. These data suggest the existence of zoonotic cycles of tapeworm infections in the direct environment of the SPC. The aim of our study was to assess the prevalence of larval cestode infections among intermediate and definitive hosts in the close neighborhood of the center. We analyzed carnivore mammal fecal samples as well as rodent carcasses, collected inside or near the SPC, using PCR. Furthermore, we performed serology for Echinococcus spp. and Taenia spp. on NHP sera. Results: We found that 14.5% (95% CI [8.6; 20.4]) of 138 carnivore feces were positive for E. multilocularis-DNA, as well as 25% (95% CI [5.5; 57.2]) of 12 rodent carcasses , and 5.1% (95% CI [1.4; 8.7]) for T. martis or T. crassiceps. Of all NHPs tested, 10.1% (95% CI [3.8; 16.4]) were seropositive for Echinococcus spp. and 8.2% (95% CI [1.3; 15.1]) for Taenia spp. Conclusions: Our data support the existence of zoonotic cycles of larval cestode infections in the direct environment of the primatology center affecting NHPs harbored in the SPC, potentially threatening the human population living in this area. Since this zoonotic risk is borne by local wildlife, and given the severity of these infections, it seems necessary to put in place measures to protect captive NHPs, and further studies to better assess the risk to human populations. Ré sumé-Des cestodoses chez des primates non humains suggèrent l'existence de cycles zoonotiques dans la région du centre de primatologie de Strasbourg. Contexte : Plusieurs cas de cestodoses larvaires dues à Echinococcus multilocularis, Taenia martis et T. crassiceps ont été récemment décrits chez des primates non-humains (PNH) captifs appartenant à diverses espèces, hébergés au Centre de Primatologie de Strasbourg (CdP). De plus, un des premiers cas humains de cysticercose due à T. martis a été décrit dans la région de Strasbourg. Ces données suggèrent l'émergence d'un nouveau foyer parasitaire dans l'environnement direct du CdP. Le but de notre étude était d'évaluer la prévalence des cestodoses larvaires chez les hôtes intermédiaires et définitifs de ces parasites dans le proche voisinage du CdP. Nous avons analysé des échantillons de selles de mammifères carnivores, ainsi que des carcasses de rongeurs, collectés à l'intérieur ou aux alentours du CdP. De plus, nous avons réalisé des sérologies pour Echinococcus spp. et Taenia spp. sur des sérums de PNH. Résultats : Nous avons trouvé que 14,5 % (IC95 % [8,6 ; 20,4]) des 138 selles de carnivores étaient positives pour E. multilocularis, ainsi que 25 % (IC95 % [5,5 ; 57,2]) des 12 carcasses de rongeur, et 5,1 % (IC95 % [1,4 ; 8,7]) pour T. martis ou T. crassiceps. De tous les PNH testés, 10,1 % (IC95 % [3,8 ; 16,4]) étaient positifs pour Echinococcus spp. et 8,2 % (IC95 % [1,3 ; 15,1]) pour Taenia spp. Conclusions : Nos données suggèrent l'existence de cycles zoonotiques de cestodoses larvaires dans l'environnement direct du centre de primatologie, affectant les PNH This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. OPEN ACCESS RESEARCH ARTICLE hébergés au CdP et menaçant potentiellement les populations humaines vivant dans cette zone. Ce risque zoonotique étant porté par la faune sauvage locale, et comptes tenus de la sévérité de ces infections, il semble nécessaire de mettre en place des mesures afin de protéger les PNH captifs, et de plus larges études afin d'évaluer le risque pour les populations humaines environnantes

Type I ROP16 regulates retinal inflammatory responses during ocular toxoplasmosis

Ocular toxoplasmosis (OT), mostly retinochorioditis, is a major feature of infection with the protozoan parasite Toxoplasma gondii. The pathophysiology of this infection is still largely elusive; especially mouse models are not yet well developed. In contrast, numerous in vitro studies showed the highly Toxoplasma strain dependent nature of the host-parasite interactions. Some distinct polymorphic virulence factors were characterized, notably the rhoptry protein ROP16. Here, we studied the strain-dependent pathophysiology in our OT mouse model. Besides of two wild type strains of the canonical I (RH, virulent) and II (PRU, avirulent) types, we used genetically engineered parasites, RH?ROP16 and PRU ROP16-I, expressing the type I allele of this virulence factor. We analyzed retinal integrity, parasite proliferation and retinal expression of cytokines. PRU parasites behaved much more virulently in the presence of a type I ROP16. In contrast, knockout of ROP16 in the RH strain led to a decrease of intraocular proliferation, but no difference in retinal pathology. Cytokine quantification in aqueous humor showed strong production of Th1 and inflammatory markers following infection with the two strains containing the ROP16-I allele. In strong contrast, immunofluorescence images showed that actual expression of most cytokines in retinal cells is rapidly suppressed by type I strain infection, with or without the involvement of its homologous ROP16 allele. This demonstrates the particular immune privileged situation of the retina, which is also revealed by the fact that parasite proliferation is nearly exclusively observed outside the retina. In summary, we further developed a promising OT mouse model and demonstrated the specific pathology in retinal tissues. © 2019 Rochet et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Detection of Pneumocystis jirovecii in Patients with Severe COVID-19: Diagnostic and Therapeutic Challenges

Cases of Pneumocystis jirovecii pneumonia (PCP) in patients suffering from COVID-19 were described in patients with various comorbidities and outcomes. The diagnosis of PCP in these patients is difficult due to clinical and radiological similarities. We carried out this study in order to better describe potentially at-risk patients and their outcomes. We retrospectively analyzed all patients with a P. jirovecii PCR performed in bronchoalveolar lavage fluid, tracheal aspirate, or sputum within a month after the COVID-19 diagnosis. Fifty-seven patients with COVID-19 infection were tested for P. jirovecii. Among 57 patients with COVID-19, four patients had a concomitant positive P. jirovecii PCR. These four patients were elderly with a mean age of 78. Two patients were immunocompromised, and the two others presented only diabetes mellitus. Three patients presented an ARDS requiring transfer to the ICU and mechanical ventilation. All patients presented lymphocytopenia. Three patients had probable PCP, and one had proven PCP. All patients died within two months after hospital admission. These co-infections are rare but severe, therefore, PCP should be considered in case of worsening of the condition of patients with severe COVID-19