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

Artificial cell research as a field that connects chemical, biological and philosophical questions

This review article discusses the interdisciplinary nature and implications of artificial cell research. It starts from two historical theories: Gánti's chemoton model and the autopoiesis theory by Maturana and Varela. They both explain the transition from chemical molecules to biological cells. These models exemplify two different ways in which disciplines of chemistry, biology and philosophy can profit from each other. In the chemoton model, conclusions from one disciplinary approach are relevant for the other disciplines. In contrast, the autopoiesis model itself (rather than its conclusions) is transferred from one discipline to the other. The article closes by underpinning the relevance of artificial cell research for philosophy with reference to the on-going philosophical debates on emergence, biological functions and biocentrism

Les nouvelles formes de participation dans les forums publics de consommateurs : vers un dispositif de co-innovation

In this researching work, we questioned the consumer’s practices of a technological and cultural product - the digital book - in public forums of discussion, with the final objective of identifying innovative consumer habits. Our interdisciplinary approach is based on the theoretical framework of the interactionism, by borrowing the key concepts of the daily interactions analysis (Erving Goffman) and of the verbal interactions (Catherine Kerbrat-Orecchioni), by joining the researches on the Documents for Action (DofA) and the Cooperative Transactions in a prospect of innovation product-market (Manuel Zacklad). In an approach of non-participating and ethical observation, we proceeded to the qualitative analysis of several threads of conversations on the digital book, observed in the forum BOOKNODE.COM. Our interpretations suggest that the consumer forum in a self-managed and self-regulated collaborative space, which the dominant activity concerns an exchange of practical knowledge, based on an expression defended from an individual standpoint or a commented and detailed experience feedback. We maintain that the consumer forum returns spontaneously not readily identifiable consumer habits. However, the absence of an analysis model satisfying to detect these uses, gave us the opportunity to build a new reading grid, then to submit a new interpretative approach. The application of our model - to deal in depth - in a co-innovative plan, results in the construction of an offer of new contents or new situations of possible consumer habits.Dans ce travail de recherche, nous avons interrogé les pratiques des consommateurs d’un produit culturel et technologique - le livre numérique - dans les forums publics de discussion, avec pour objectif final d’identifier des usages de consommation innovants. Notre approche transdisciplinaire, s’est appuyée sur le cadre théorique de l’interactionnisme, en empruntant les concepts clés, de l’analyse des interactions quotidiennes (Erving Goffman) et de l’analyse des interactions verbales (Catherine Kerbrat-Orecchioni), en s’inscrivant dans les recherches sur le Document pour l’Action et des transactions coopératives dans une perspective d’innovation produit-marché (Manuel Zacklad). Dans une démarche d’observation non participante et éthique, nous avons procédé à l’analyse qualitative de plusieurs fils de conversation sur le livre numérique, issus du forum BOOKNODE.COM. Nos interprétations suggèrent que le forum de consommateurs est un espace collaboratif auto-géré/auto-régulé, dont l’activité dominante porte sur un échange de connaissances pratiques, reposant sur une expression argumentée d’un point de vue individuel ou un retour d’expérience commenté et détaillé. Nous soutenons que le forum de consommateurs restitue spontanément des usages de consommation difficilement décelables pour l’enquêteur. Toutefois, l’absence d’un modèle d’analyse satisfaisant pour déceler ces usages nous a donné l’occasion de construire une nouvelle grille de lecture, de suggérer une démarche interprétative. L’application de notre modèle - à améliorer - dans un dispositif de co-innovation, aboutit à la construction d’une offre de nouveaux contenus et de nouvelles situations d’usages possibles

The new participative forms in public consumer forum : towards a plan of co-innovation

Dans ce travail de recherche, nous avons interrogé les pratiques des consommateurs d’un produit culturel et technologique - le livre numérique - dans les forums publics de discussion, avec pour objectif final d’identifier des usages de consommation innovants. Notre approche transdisciplinaire, s’est appuyée sur le cadre théorique de l’interactionnisme, en empruntant les concepts clés, de l’analyse des interactions quotidiennes (Erving Goffman) et de l’analyse des interactions verbales (Catherine Kerbrat-Orecchioni), en s’inscrivant dans les recherches sur le Document pour l’Action et des transactions coopératives dans une perspective d’innovation produit-marché (Manuel Zacklad). Dans une démarche d’observation non participante et éthique, nous avons procédé à l’analyse qualitative de plusieurs fils de conversation sur le livre numérique, issus du forum BOOKNODE.COM. Nos interprétations suggèrent que le forum de consommateurs est un espace collaboratif auto-géré/auto-régulé, dont l’activité dominante porte sur un échange de connaissances pratiques, reposant sur une expression argumentée d’un point de vue individuel ou un retour d’expérience commenté et détaillé. Nous soutenons que le forum de consommateurs restitue spontanément des usages de consommation difficilement décelables pour l’enquêteur. Toutefois, l’absence d’un modèle d’analyse satisfaisant pour déceler ces usages nous a donné l’occasion de construire une nouvelle grille de lecture, de suggérer une démarche interprétative. L’application de notre modèle - à améliorer - dans un dispositif de co-innovation, aboutit à la construction d’une offre de nouveaux contenus et de nouvelles situations d’usages possibles.In this researching work, we questioned the consumer’s practices of a technological and cultural product - the digital book - in public forums of discussion, with the final objective of identifying innovative consumer habits. Our interdisciplinary approach is based on the theoretical framework of the interactionism, by borrowing the key concepts of the daily interactions analysis (Erving Goffman) and of the verbal interactions (Catherine Kerbrat-Orecchioni), by joining the researches on the Documents for Action (DofA) and the Cooperative Transactions in a prospect of innovation product-market (Manuel Zacklad). In an approach of non-participating and ethical observation, we proceeded to the qualitative analysis of several threads of conversations on the digital book, observed in the forum BOOKNODE.COM. Our interpretations suggest that the consumer forum in a self-managed and self-regulated collaborative space, which the dominant activity concerns an exchange of practical knowledge, based on an expression defended from an individual standpoint or a commented and detailed experience feedback. We maintain that the consumer forum returns spontaneously not readily identifiable consumer habits. However, the absence of an analysis model satisfying to detect these uses, gave us the opportunity to build a new reading grid, then to submit a new interpretative approach. The application of our model - to deal in depth - in a co-innovative plan, results in the construction of an offer of new contents or new situations of possible consumer habits

The level of satisfaction of patients undergoing intravenous pyelography procedure at the National Kidney and Transplant Institute

The descriptive method of research was employed. The respondents were limited to first 200 patients of the NKTI regardless of their gender, age, civil status and educational attainment chosen using non-proportional quota sampling. The data gathering instrument used was a self-made questionnaire for the patients undergoing intravenous pyelography examinations at NKTI. The statistical tools employed were percentage, t-test, frequency, f-test, mean and standard deviation. Majority of the respondents were males, aged 41 years old and above, married and reached college level. Overall mean of patients’ satisfaction in IVP procedures at NKTI obtained the highest satisfaction in terms of pre, intra, and post-procedures

Staphylococcus lugdunensis: a neglected pathogen of infections involving fracture-fixation devices

International audiencePurpose Cases of fracture-fixation device infection involving Staphylococcus lugdunensis are not frequent. The clinical characteristics and the choice of treatment strategies of these infections are not obviously known to date. Methods We performed a review of fracture-fixation device infection involving S. lugdunensis managed by our centres. Results Among the 38 cases of fracture-fixation device infection involving S. lugdunensis, 53% were located in the tibia. Most of our cases (87%) were chronic infections. Purulent discharge, which occurred in 79% of cases, was the most frequent clinical symptom, followed by pain in 63%, local inflammation in 55%, and fever in 37%. Bacteremia and severe sepsis occurred in 10% and 18% of cases, respectively. Four cases (10%) were treated exclusively with antimicrobial treatment alone. Thirty-four cases (89%) were treated with a combination of surgery with antimicrobial therapy including surgical debridement, antibiotics and osteosynthesis device retention in six cases (16%), and osteosynthesis device removal in 27 cases (71%). The mean length of antibiotic treatment was 119 days. The relapse rate was high that was not related to selection of resistant strains. Polymicrobial infection had no impact on clinical outcome. A combination of surgery with antimicrobial therapy was identified as a significant prognostic factor associated with remission (p = 0.042). Conclusions S. lugdunensis is probably involved in more infections than has been reported. Using appropriate microbiological methods laboratories should routinely identify the species of all coagulase-negative Staphylococci isolates involved in fracture-fixation device infection to better achieve the treatment strategies of fracture-fixation device infection involving S. lugdunensis

Existence of a colonizing Staphylococcus aureus strain isolated in diabetic foot ulcers.

Affiliations ECOFECTInternational audiencePhylogenetic tree reconciliation is the approach of choice for investigating the coevolution of sets of organisms such as hosts and parasites. It consists in a mapping between the parasite tree and the host tree using event-based maximum parsimony. Given a cost model for the events, many optimal reconciliations are however possible. Any further biological interpretation of them must therefore take this into account, making the capacity to enumerate all optimal solutions a crucial point. Only two algorithms currently exist that attempt such enumeration; in one case not all possible solutions are produced while in the other not all cost vectors are currently handled. The objective of this paper is two-fold. The first is to fill this gap, and the second is to test whether the number of solutions generally observed can be an issue in terms of interpretation. We present a polynomial-delay algorithm for enumerating all optimal reconciliations. We show that in general many solutions exist. We give an example where, for two pairs of host-parasite trees having each less than 41 leaves, the number of solutions is 5120, even when only time-feasible ones are kept. To facilitate their interpretation, those solutions are also classified in terms of how many of each event they contain. The number of different classes of solutions may thus be notably smaller than the number of solutions, yet they may remain high enough, in particular for the cases where losses have cost 0. In fact, depending on the cost vector, both numbers of solutions and of classes thereof may increase considerably. To further deal with this problem, we introduce and analyse a restricted version where host switches are allowed to happen only between species that are within some fixed distance along the host tree. This restriction allows us to reduce the number of time-feasible solutions while preserving the same optimal cost, as well as to find time-feasible solutions with a cost close to the optimal in the cases where no time-feasible solution is found. We present Eucalypt, a polynomial-delay algorithm for enumerating all optimal reconciliations which is freely available at http://eucalypt.gforge.inria.fr/

Addition of Androgens Improves Survival in Elderly Patients With Acute Myeloid Leukemia: A GOELAMS Study

International audiencePurpose Elderly patients with acute myeloid leukemia (AML) have a poor prognosis, and innovative maintenance therapy could improve their outcomes. Androgens, used in the treatment of aplastic anemia, have been reported to block proliferation of and initiate differentiation in AML cells. We report the results of a multicenter, phase III, randomized open-label trial exploring the benefit of adding androgens to maintenance therapy in patients 60 years of age or older. Patients and Methods A total of 330 patients with AML de novo or secondary to chemotherapy or radiotherapy were enrolled in the study. Induction therapy included idarubicin 8 mg/m 2 on days 1 to 5, cytarabine 100 mg/m 2 on days 1 to 7, and lomustine 200 mg/m 2 on day 1. Patients in complete remission or partial remission received six reinduction courses, alternating idarubicin 8 mg/m 2 on day 1, cytarabine 100 mg/m 2 on days 1 to 5, and a regimen of methotrexate and mercaptopurine. Patients were randomly assigned to receive norethandrolone 10 or 20 mg/day, according to body weight, or no norethandrolone for a 2-year maintenance therapy regimen. The primary end point was disease-free survival by intention to treat. Secondary end points were event-free survival, overall survival, and safety. This trial was registered at www.ClinicalTrials.gov identifier NCT00700544. Results Random assignment allotted 165 patients to each arm; arm A received norethandrolone, and arm B did not receive norethandrolone. Complete remission or partial remission was achieved in 247 patients (76%). The Schoenfeld time-dependent model showed that norethandrolone significantly improved survival for patients still in remission at 1 year after induction. In arms A and B, respectively, 5-year disease-free survival was 31.2% and 16.2%, event-free survival was 21.5% and 12.9%, and overall survival was 26.3% and 17.2%. Norethandrolone improved outcomes irrelevant to all prognosis factors. Only patients with baseline leukocytes. 30 3 10 9 /L did not benefit from norethandrolone. Conclusion This study demonstrates that maintenance therapy with norethandrolone significantly improves survival in elderly patients with AML without increasing toxicity