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

Impact of systematic whole-body 18F-fluorodeoxyglucose PET/CT on the management of patients suspected of infective endocarditis: the prospective multicenter TEPvENDO study

International audienceBackground - Diagnostic and patients' management modifications induced by whole-body 18F-FDG-PET/CT had not been evaluated so far in prosthetic valve (PV) or native valve (NV) infective endocarditis (IE)-suspected patients. Methods - In sum, 140 consecutive patients in 8 tertiary care hospitals underwent 18F-FDG-PET/CT. ESC-2015-modified Duke criteria and patients' management plan were established jointly by 2 experts before 18F-FDG-PET/CT. The same experts reestablished Duke classification and patients' management plan immediately after qualitative interpretation of 18F-FDG-PET/CT. A 6-month final Duke classification was established. Results - Among the 70 PV and 70 NV patients, 34 and 46 were classified as definite IE before 18F-FDG-PET/CT. Abnormal perivalvular 18F-FDG uptake was recorded in 67.2% PV and 24.3% NV patients respectively (P < .001) and extracardiac uptake in 44.3% PV and 51.4% NV patients. IE classification was modified in 24.3% and 5.7% patients (P = .005) (net reclassification index 20% and 4.3%). Patients' managements were modified in 21.4% PV and 31.4% NV patients (P = .25). It was mainly due to perivalvular uptake in PV patients and to extra-cardiac uptake in NV patients and consisted in surgery plan modifications in 7 patients, antibiotic plan modifications in 22 patients and both in 5 patients. Altogether, 18F-FDG-PET/CT modified classification and/or care in 40% of the patients (95% confidence interval: 32-48), which was most likely to occur in those with a noncontributing echocardiography (P < .001) or IE classified as possible at baseline (P = .04), while there was no difference between NV and PV. Conclusions - Systematic 18F-FDG-PET/CT did significantly and appropriately impact diagnostic classification and/or IE management in PV and NV-IE suspected patients. Clinical trials registration - NCT02287792

High-risk exposure without personal protective equipment and infection with SARS-CoV-2 in-hospital workers - The CoV-CONTACT cohort.

International audienc

High-risk exposure without personal protective equipment and infection with SARS-CoV-2 in-hospital workers - The CoV-CONTACT cohort

International audienc

High-risk exposure without personal protective equipment and infection with SARS-CoV-2 in-hospital workers - The CoV-CONTACT cohort

International audienc