Caractéristiques des pneumocystoses à Nancy entre janvier 2007 et avril 2011 et focus sur une épidémie en néphrologie

International audienceBackgroundPneumocystis jirovecii is responsible for pneumonia in immunocompromised populations. Pneumocystis pneumonia has first been discovered as a common and life-threatening opportunistic infection in HIV-infected patients.ObjectivesThe aim of this study is to characterize the epidemiological aspects of Pneumocystis pneumonia and then to highlight an outbreak of this infection in a nephrology unit with molecular tools.Patients/MethodsA multilocus sequence typing method has been used to study the epidemiology of strains isolated during this episode.ResultsFrom January 2007 to April 2011, 39 cases of P. jirovecii pneumonia have been observed. In two thirds of cases, underlying diseases as transplantations, hematologic or solid malignancies, or immunodepressed treatment were the main risk factors and in one third of cases, there were HIV positive patients. This distribution is due to an outbreak of 13 cases in a nephrology unit, where the MLST resulted in two strains profiles regrouping each one 6 and 4 cases among the 10 available isolates.ConclusionsNew categories of risk patients of Pneumocystis infection have emerged with severe clinical manifestations and mostly with a fatal outcome. The origin of the transmission is still unknown but a local transmission has been showed in our nephrology unit.ContextePneumocystis jirovecii est responsable de pneumopathies chez les patients immunodéprimés. La pneumocystose était considérée initialement comme une infection opportuniste, commune et potentiellement mortelle des patients infectés par le VIH.ObjectifsLes objectifs de cette étude sont de caractériser sur le plan épidémiologique des pneumocystoses et de mettre en évidence une épidémie dans un service de néphrologie par des outils moléculaires.Patients/MéthodesUne technique de MLST a étudié les caractéristiques moléculaires des souches de P. jirovecii isolées en néphrologie.RésultatsDe janvier 2007 à avril 2011, 39 cas de pneumocystose ont été observés. Dans deux tiers des cas, les principaux facteurs de risque sont les traitements immunosuppresseurs et les pathologies sous-jacentes telles que les transplantations, les hémopathies malignes ou les tumeurs solides. Dans un tiers des cas, les patients étaient infectés par le VIH. Cette répartition est due à une épidémie de 13 cas survenue dans le service de néphrologie. Le typage moléculaire a déterminé deux types de profils parmi les 10 isolats disponibles, regroupant chacun 6 et 4 cas.ConclusionsDe nouvelles catégories de patients à risque de pneumocystose ont émergé et les manifestations cliniques y sont sévères et généralement associées à un mauvais pronostic. L’origine de cette infection est encore inconnue mais une transmission locale a été observée dans un service de néphrologie

Comparison of two DNA sequence-based typing schemes for the Fusarium solani Species Complex and proposal of a new consensus method

Multilocus sequence typing (MLST) is a widely used approach for differentiating microbial isolates presenting many advantages such as easy access through online databases and straightforward interpretation. For the Fusarium solani species complex (FSSC). three gene regions have been widely used to investigate phylogenetic relationships at the interspecific level (ITS-nuLSU, EF1a, RPB2) and a nomenclature system has been proposed for the different known haplotypes. More recently, a MLST scheme was proposed for this species complex based on the polymorphisms of five housekeeping genes (ACC, ICL, GDP, MDP, SOD). Here, we compare the phylogenetic resolution and sequence discriminatory powers of these two sets of loci on 50 epidemiologically unrelated FSSC strains. Although the widely used gene set offers better phylogenetic resolution, the newly developed gene set is slightly better at discriminating isolates using a MIST method. A consensus scheme of eight loci is proposed for typing FSSC strains combining the advantages of the two previous gene sets and offering the best typing efficiency. (C) 2012 Elsevier B.V. All rights reserved

Development of a new MLST scheme for differentiation of Fusarium solani Species Complex (FSSC) isolates

Fungi belonging to the Fusarium solani Species Complex (FSSC) are well known plant pathogens. In addition to being the causative agent of some superficial infections, FSSC has recently emerged as a group of common opportunistic moulds, mainly in patients with haematological malignancies. Molecular typing methods are essential in order to better understand the epidemiology of such opportunistic agents with the final goal of preventing contamination. A three-locus typing scheme has thus been developed for FSSC; based on polymorphisms in the domains of the ITS, EF-1 alpha, and RPB2 genes. This method is now considered to be a useful reference for phylogenetic and taxonomic studies. In other significant clinical fungi (e.g., Candida sp., Cryptococcus neoformans, and Aspergillus fumigatus), genes coding for metabolic enzymes have been widely used and proven to be very informative for diagnosis and epidemiology. The contribution of these genes has never been evaluated for Fusarium sp. and more specifically for F. solani Species Complex. Here, we have evaluated the contribution of 25 genes for diagnosis and epidemiological purposes. We then report a new five-locus MLST scheme useful for diagnosis and typing of clinical FSSC isolates. The method has been validated on 51 epidemiologically unrelated strains of FSSC and presents a high power of discrimination calculated at 0.991