Staphylococcus aureus infective endocarditis versus bacteremia strains: Subtle genetic differences at stake

AbstractInfective endocarditis (IE)(1) is a severe condition complicating 10–25% of Staphylococcus aureus bacteremia. Although host-related IE risk factors have been identified, the involvement of bacterial features in IE complication is still unclear. We characterized strictly defined IE and bacteremia isolates and searched for discriminant features. S. aureus isolates causing community-acquired, definite native-valve IE (n=72) and bacteremia (n=54) were collected prospectively as part of a French multicenter cohort. Phenotypic traits previously reported or hypothesized to be involved in staphylococcal IE pathogenesis were tested. In parallel, the genotypic profiles of all isolates, obtained by microarray, were analyzed by discriminant analysis of principal components (DAPC)(2). No significant difference was observed between IE and bacteremia strains, regarding either phenotypic or genotypic univariate analyses. However, the multivariate statistical tool DAPC, applied on microarray data, segregated IE and bacteremia isolates: IE isolates were correctly reassigned as such in 80.6% of the cases (C-statistic 0.83, P<0.001). The performance of this model was confirmed with an independent French collection IE and bacteremia isolates (78.8% reassignment, C-statistic 0.65, P<0.01). Finally, a simple linear discriminant function based on a subset of 8 genetic markers retained valuable performance both in study collection (86.1%, P<0.001) and in the independent validation collection (81.8%, P<0.01). We here show that community-acquired IE and bacteremia S. aureus isolates are genetically distinct based on subtle combinations of genetic markers. This finding provides the proof of concept that bacterial characteristics may contribute to the occurrence of IE in patients with S. aureus bacteremia

Th 3 Co 3 Sb 4 : A New Room Temperature Magnet IN HONOR OF PROFESSOR PAUL HAGENMULLER ON THE OCCASION OF HIS 80TH BIRTHDAY

The new ternary compound Th 3 Co 3 Sb 4 was synthesized by arc melting. The compound crystallizes in the cubic space group I-43d (No. 220) with a ‫؍‬ 9.572(2) A s and adopts the Y 3 Au 3 Sb 4 structure, which is a 5lled version of the Th 3 P 4 structure type. The crystal structure was solved and re5ned with single-crystal X-ray di4raction. Final R1/Rw2 ‫؍‬ 1.52/3.73%. Th 3 Co 3 Sb 4 is a metallic ferromagnet at room temperature. Electrical conductivity and thermoelectric power measurements show metallic behavior, which is also predicted by the electronic band structure calculations

Synthesis and crystal structure of K5InTe4,KCl

International audienc

Une remise en question dans le système ternaire lithium-zinc-germanium : la phase LiZnGe présentant une surstructure hexagonale.

International audienc

Une remise en question dans le système ternaire lithium-zinc-germanium : la phase LiZnGe présentant une surstructure hexagonale.

International audienc

Synthesis and crystal structure of a salt containing the trans-diphenyldi-*-seleno-diseleno-distannate (2-) anion.

International audienc

Crystal structure of potassium-indium-germanium alloy K8In6Ge40.

International audienc

Crystal structure of potassium-indium-germanium alloy K8In6Ge40.

International audienc

Heteroatomic polyanions of post-transition elements. Synthesis and structure of a salt containing the novel tetra antimony hexaselenate (2-) anion [Sb4Se6]2-.

International audienc

Crystal and electronic structure of the ternary phase LiZnGe.

International audienc