Usefulness of matrix-assisted laser desorption ionisation-time-of-flight mass spectrometry for identifying clinical Trichosporon isolates.

Trichosporon spp. have recently emerged as significant human pathogens. Identification of these species is important, both for epidemiological purposes and for therapeutic management, but conventional identification based on biochemical traits is hindered by the lack of updates to the species databases provided by the different commercial systems. In this study, 93 strains, or isolates, belonging to 16 Trichosporon species were subjected to both molecular identification using IGS1 gene sequencing and matrix-assisted laser desorption ionisation-time-of-flight (MALDI-TOF) analysis. Our results confirmed the limits of biochemical systems for identifying Trichosporon species, because only 27 (36%) of the isolates were correctly identified using them. Different protein extraction procedures were evaluated, revealing that incubation for 30 min with 70% formic acid yields the spectra with the highest scores. Among the six different reference spectra databases that were tested, a specific one composed of 18 reference strains plus seven clinical isolates allowed the correct identification of 67 of the 68 clinical isolates (98.5%). Although until recently it has been less widely applied to the basidiomycetous fungi, MALDI-TOF appears to be a valuable tool for identifying clinical Trichosporon isolates at the species level.

[Experience of targeted screening of Chagas disease in Ile-de-France]. / Expérience de dépistage ciblé de la maladie de Chagas en Ile-de-France.

2009 is marked by the centenary of the discovery by Carlos Chagas of Human American Trypanosomiasis. As a result of international cooperation its incidence has been falling in endemic areas, whereas North America and Europe are witnessing an increase in the number of imported cases. In metropolitan France, 18 such cases were reported between 2004 and 2007. Recently, estimates based on immigration figures have been made and suggest that about 1,500 imported cases can be expected in France. The object of this article is to assess the value of targeted screening of an at-risk population, originally from Latin America and now living in the Ile-de-France (area centred on Paris). The serological techniques employed were indirect immunofluorescence (IIF) and, depending on the case, 2 or 3 Elisa tests (Biomérieux, Biokit and Wiener). Trypanosoma cruzi serology was considered positive when the IIF was superior or equal to 200, or when two Elisa's were > 1, or when the IIF was superior or equal to 100 with at least one Elisa > 1. PCR was performed in 48 cases, which were considered to be positive. The tests were carried out on a voluntary basis after a publicity campaign within the Latin American community in the Ile-de-France. In this article, we present the findings of the first year of screening. Two hundred and fifty-four individuals were screened for Chagas' disease between June 2008 and June 2009. The median age was 33 years [11-63], the male/female ratio 102/152. Overall prevalence of positive serology was 23.6% (60/254). For six patients, the results were classified as "uncertain" (discordant serological tests). Of the seropositive group, 87.4% were Bolivian and 100% presented as a chronic form. Of these, 23.6% presented with functional cardiac manifestations and 22% with gastro-intestinal problems. The PCR was positive in 61% of the seropositive individuals. Clinical evaluation together with other investigations and therapeutic intervention is being carried out at present. These results confirm that metropolitan France is subject to the emergence of Chagas' disease in a non-endemic zone. This confirms the value of screening in at-risk populations, in particular because of the recent broadening of indications for antiparasitic treatment. In addition it is relevant to the prevention of vertical transmission or infection via organ donation, which could arise in France. These results also demonstrate continuing difficulties in the interpretation of serological results and the usefulness of PCR, which might increase sensitivity substantially.

[Chagas disease in chronic phase outside the endemic area. The diagnostic tools]. / Maladie de Chagas en phase chronique hors zone d'endémie. Les outils diagnostiques.

The diagnosis of Chagas disease during the chronic phase is based on serology. Outside South America the use of two methods is recommended by WHO. A third method must be available for inconclusive results but there is no gold standard. A pilot study of screening in 254 Bolivian people living in the Paris area (France) was made. Serological study was performed using IIF and three Elisa, Elisa Cruzi (BioMérieux Brésil), BioElisa Chagas (Bio-kit), and Chagatest Elisa recombinante v. 3.0 (Wiener Lab). 165 patients were negative, 69 positive and 20 inconclusive. PCR-based assays appear to have a better sensitivity than parasitological methods, but not more than 70% that do not justify their use for primary testing. There are no standardized and commercial assays. The primer pairs based on the nuclear sequence TCZ1-TCZ2 seems to be the more specific (no cross reaction with others Trypanosomatidae) and the most sensitive with the strains of the two lineage of Trypanosoma cruzi. PCR would have a role in inconclusive serological cases or in the evaluation of treatment failure.