Real-Time PCR for Diagnosis of Oculoglandular Tularemia

International audienc

Tularemia treatment: experimental and clinical data

Tularemia is a zoonosis caused by the Gram negative, facultative intracellular bacterium Francisella tularensis. This disease has multiple clinical presentations according to the route of infection, the virulence of the infecting bacterial strain, and the underlying medical condition of infected persons. Systemic infections (e.g., pneumonic and typhoidal form) and complications are rare but may be life threatening. Most people suffer from local infection (e.g., skin ulcer, conjunctivitis, or pharyngitis) with regional lymphadenopathy, which evolve to suppuration in about 30% of patients and a chronic course of infection. Current treatment recommendations have been established to manage acute infections in the context of a biological threat and do not consider the great variability of clinical situations. This review summarizes literature data on antibiotic efficacy against F. tularensis in vitro, in animal models, and in humans. Empirical treatment with beta-lactams, most macrolides, or anti-tuberculosis agents is usually ineffective. The aminoglycosides gentamicin and streptomycin remain the gold standard for severe infections, and the fluoroquinolones and doxycycline for infections of mild severity, although current data indicate the former are usually more effective. However, the antibiotic treatments reported in the literature are highly variable in their composition and duration depending on the clinical manifestations, the age and health status of the patient, the presence of complications, and the evolution of the disease. Many patients received several antibiotics in combination or successively. Whatever the antibiotic treatment administered, variable but high rates of treatment failures and relapses are still observed, especially in patients treated more then 2–3 weeks after disease onset. In these patients, surgical treatment is often necessary for cure, including drainage or removal of suppurative lymph nodes or other infectious foci. It is currently difficult to establish therapeutic recommendations, particularly due to lack of comparative randomized studies. However, we have attempted to summarize current knowledge through proposals for improving tularemia treatment which will have to be discussed by a group of experts. A major factor in improving the prognosis of patients with tularemia is the early administration of appropriate treatment, which requires better medical knowledge and diagnostic strategy of this disease

Toxoplasmosis in transplant recipients, Europe, 2010-2014

Transplantation activity is increasing, leading to a growing number of patients at risk for toxoplasmosis. We reviewed toxoplasmosis prevention practices, prevalence, and outcomes for hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT; heart, kidney, or liver) patients in Europe. We collected electronic data on the transplant population and prevention guidelines/regulations and clinical data on toxoplasmosis cases diagnosed during 2010-2014. Serologic pretransplant screening of allo-hematopoietic stem cell donors was performed in 80% of countries, screening of organ donors in 100%. SOT recipients were systematically screened in 6 countries. Targeted anti-Toxoplasma chemoprophylaxis was heterogeneous. A total of 87 toxoplasmosis cases were recorded (58 allo-HSCTs, 29 SOTs). The 6-month survival rate was lower among Toxoplasma-seropositive recipients and among allo-hematopoietic stem cell and liver recipients. Chemoprophylaxis improved outcomes for SOT recipients. Toxoplasmosis remains associated with high mortality rates among transplant recipients. Guidelines are urgently needed to standardize prophylactic regimens and optimize patient management

H3K27me3 Profiling of the Endosperm Implies Exclusion of Polycomb Group Protein Targeting by DNA Methylation

Polycomb group (PcG) proteins act as evolutionary conserved epigenetic mediators of cell identity because they repress transcriptional programs that are not required at particular developmental stages. Each tissue is likely to have a specific epigenetic profile, which acts as a blueprint for its developmental fate. A hallmark for Polycomb Repressive Complex 2 (PRC2) activity is trimethylated lysine 27 on histone H3 (H3K27me3). In plants, there are distinct PRC2 complexes for vegetative and reproductive development, and it was unknown so far whether these complexes have target gene specificity. The FERTILIZATION INDEPENDENT SEED (FIS) PRC2 complex is specifically expressed in the endosperm and is required for its development; loss of FIS function causes endosperm hyperproliferation and seed abortion. The endosperm nourishes the embryo, similar to the physiological function of the placenta in mammals. We established the endosperm H3K27me3 profile and identified specific target genes of the FIS complex with functional roles in endosperm cellularization and chromatin architecture, implicating that distinct PRC2 complexes have a subset of specific target genes. Importantly, our study revealed that selected transposable elements and protein coding genes are specifically targeted by the FIS PcG complex in the endosperm, whereas these elements and genes are densely marked by DNA methylation in vegetative tissues, suggesting that DNA methylation prevents targeting by PcG proteins in vegetative tissues

Caractérisation biochimique et génétique d'une souche de Francisella sp. : description du premier cas d'infection humaine à Francisella salimarina

International audienceLe genre Francisella comprend un grand nombre d’espèces mais seules F. tularensissubspecies tularensis et F. tularensis subsp. holarctica causent la tularémie, infection potentiellement mortelle. Les espèces F. philomiragia, F. novicida, F. opportunistica et F. hispaniensis sont des pathogènes humains occasionnels. Le laboratoire de Bactériologie du CHU Grenoble Alpes est Centre National de Référence (CNR) des Francisella. Dans ce contexte, une souche de Francisella sp. (CHUGA-F75), isolée d’hémoculture et d’ulcère cutané chez un patient immunodéprimé sous chimiothérapie, a été adressée au laboratoire pour typage. Nous avons procédé à la caractérisation biochimique et génétique de cette souche. La souche CHUGA-F75 était aérobie stricte, capable de croissance en 24 heures sur gélose chocolat supplémentée en IsoVitaleX mais aussi sur gélose au sang et gélose trypticase soja, par opposition à F. tularensis. La souche était halotolérante, capable de croitre dans des milieux contenant jusqu’à 8% de NaCl, ce qui la distinguait également de F. tularensis. L’identification à l’espèce de la souche CHUGA-F75 n’a pas pu être obtenue par spectrométrie de masse MALDI-TOF avec des bases de données contenant les espèces F. tularensis, F. novicida et F. philomiragia. Les PCR (ISFtu2, Tul4, Type B), amplifiant les bactéries du genre Francisella, habituellement utilisées au CNR, n’ont pas conduit à une amplification. C’est pourquoi, le génome complet de la souche CHUGA-F75 a été séquencé par des technologies de séquençage de 2ème génération (MiSeq, Illumina) et de 3ème génération (MinION, Oxford Nanopore). Un assemblage hybride des données de séquençage a été réalisé en utilisant le logiciel Unicycler sur la plateforme Galaxy et a permis la construction d’un chromosome circulaire de 1 940 863 bp. L’identification à l’espèce de la souche CHUGA-F75 à partir des données de génome complet a été réalisée à l’aide du Type Strain Genome Server (https://tygs.dsmz.de) qui a placé cette souche sur la même branche que les souches F. salimarina SYSU SYW-1, F. marina E95-16 et F. salina TX07-7308. Ces trois souches ainsi que la souche CHUGA-F75 présentaient un taux d’hybridation ADN-ADN supérieur à 70% et un ANI (Average Nucleotide Identity) supérieur à 95% suggérant qu’elles appartenaient à une seule et même espèce, bien que plusieurs noms d’espèces aient été proposés. La souche CHUGA-F75 a donc été identifiée comme une F. salimarina, seul nom d’espèce validé par le code international des nomenclatures. F. marina a été décrite comme responsable d’infection de poissons en Amérique centrale, F. salimarina a été isolée d’eau de mer côtière en Chine et F. salina a été isolée d’eau de mer côtière et d’algues aux Etats-Unis. Ainsi, il s’agirait de la première description d’infection humaine à F. salimarina. La source d’infection du patient n’a pas pu être identifiée mais une origine aquatique pourrait être suspectée en raison des réservoirs aquatiques marins décrits préalablement pour cette espèce et du lieu de résidence du patient, proche de l’océan Atlantique. Cette description s’inscrit dans la thématique de recherche du CNR portant sur la survie aquatique des Francisella

Presence of Francisella tularensis subsp. holarctica DNA in the Aquatic Environment in France

International audienceIn 2018, the incidence of tularemia increased twofold in the west of France, with many pneumonic forms, suggesting environmental sources of infection. We investigated the presence of Francisellatularensis subsp. holarctica and other Francisella species DNA in the natural aquatic environment of this geographic area. Two sampling campaigns, in July 2019 and January 2020, allowed the collection of 87 water samples. Using a combination of real-time PCR assays, we tested the presence of either Francisella sp., F. tularensis/F. novicida, and F. tularensis subsp. holarctica, the latter being the only tularemia agent in Europe. Among 57 water samples of the first campaign, 15 (26.3%) were positive for Francisella sp., nine (15.8%) for F. tularensis and/or F. novicida, and four (7.0%) for F. tularensis subsp. holarctica. Ratios were 25/30 (83.3%), 24/30 (80.0%), and 4/30 (13.3%) for the second campaign. Among the thirty sites sampled during the two campaigns, nine were positive both times for Francisella sp., seven for F. tularensis and/or F. novicida, and one for F. tularensis subsp. holarctica. Altogether, our study reveals a high prevalence of Francisella sp. DNA (including the tularemia agent) in the studied aquatic environment. This aquatic environment could therefore participate in the endemicity of tularemia in the west of France

Several Nocardia abcessus bronchiolitis in a patient treated with inhaled corticosteroids: a case report

Abstract Nocardiosis is a disease that mainly affects immunocompromised patients. Inhaled corticosteroids (ICS) are standard of care for asthma. This treatment can induce respiratory infections but no case of bronchiolitis nocardiosis have been described so far. A 58-year-old man, with history of controlled moderate allergic asthma, develop an increased cought in the last two years associated with dyspnea on exertion. Within two months, although ICS were increased to high doses, symptoms worsened due to a severe obstructive ventilatory disorder as revealed by pulmonary function tests (PFT). Small-scale lesions (< 10%) were found on chest computed tomography (CT). A bronchoalveolar lavage (BAL) found Nocardia abcessus. After six months of Sulfamethoxazole/Trimethoprim, PFT results improved and chest CT became completely normal. We therefore present the case of a bronchiolitis nocardiosis with several bronchial syndrome and the only immunosuppressive factor found were ICS

Human tularemia in France, 2006-2010.

International audienceBACKGROUND: Tularemia is an endemic but rare disease in France. We describe the epidemiologic, clinical, diagnostic, treatment, and prognostic aspects of the disease in 101 consecutive patients investigated during a 5-year period (2006-2010). METHODS: All tularemia cases confirmed at the French Reference Center for Tularemia (FRCT) were included. Data were collected both at the Institut de Veille Sanitaire (mandatory notification) and FRCT. Diagnostic methods included serological tests (microagglutination and indirect immunofluorescence assay), Francisella tularensis cultures, real-time polymerase chain reaction (RT-PCR) tests, and molecular identification of the F. tularensis subspecies involved. RESULTS: The patient cohort consisted of 55 men and 46 women (sex ratio, 1.2; average age, 51.7 years), including 93 sporadic cases that occurred throughout France. Contaminations occurred predominantly through contact with or ingestion of lagomorphs (31.7%), tick bites (10.9%), or contaminated environments (7.9%). The glandular and ulceroglandular forms predominated (57.5% of cases), but 18.8% of patients experienced a systemic disease and 29.7% were hospitalized. Specific diagnosis was mainly based on serology, but 38.6% of patients had positive RT-PCR tests and 20.8% had a positive culture. F. tularensis subspecies holarctica was identified in 25 patients. All patients except 1 recovered from infection, but 38.6% experienced relapses despite appropriate antibiotic therapy. CONCLUSIONS: The epidemiological and clinical aspects of tularemia in France are varied, suggesting different modes of contamination. The high rates of systemic diseases and hospitalization indicate that the more serious cases are more likely to be diagnosed and notified. RT-PCR tests may help to improve diagnosis and reporting of the disease

Two cases of type A infant botulism in Grenoble, France: no honey for infants.

International audienceWe report two severe cases of infant botulism diagnosed at Grenoble University Hospital, France, respectively in 2006 and 2009. Both cases were characterized by a delay in diagnosis, severe neurological manifestations and extended period of hospitalization in intensive care unit, but a complete recovery. Infant botulism is a rare but life-threatening disease. It primarily affects infants, and the main risk factor is honey ingestion. Diagnosis should be systematically evoked by pediatricians in infants suffering from constipation, fatigue, muscle weakness, difficult feeding and altered cry, but before the onset of generalized flaccid paralysis, so as to administer specific treatment (BabyBIG®, a human derived botulinum antitoxin) at an early stage of the disease when it is most effective. In conclusion, parents should be aware of the role of honey as a source of spores of Clostridium botulinum and therefore infant botulism in the first year of life