Evidence of niche partitioning among bacteria living on plastics, organic particles and surrounding seawaters.

Plastic pollution is widespread in ocean ecosystems worldwide, but it is unknown if plastic offers a unique habitat for bacteria compared to communities in the water column and attached to naturally-occurring organic particles. The large set of samples taken during the Tara-Mediterranean expedition revealed for the first time a clear niche partitioning between free-living (FL), organic particle-attached (PA) and the recently introduced plastic marine debris (PMD). Bacterial counts in PMD presented higher cell enrichment factors than generally observed for PA fraction, when compared to FL bacteria in the surrounding waters. Taxonomic diversity was also higher in the PMD communities, where higher evenness indicated a favorable environment for a very large number of species. Cyanobacteria were particularly overrepresented in PMD, together with essential functions for biofilm formation and maturation. The community distinction between the three habitats was consistent across the large-scale sampling in the Western Mediterranean basin. 'Plastic specific bacteria' recovered only on the PMD represented half of the OTUs, thus forming a distinct habitat that should be further considered for understanding microbial biodiversity in changing marine ecosystems.

[Diagnostic delay in Horton's disease. Analysis of the diagnostic delay based on a retrospective study of 130 cases]. / Le retard diagnostique dans la maladie de Horton. Analyse du délai diagnostique à partir d'une étude rétrospective de 130 cas.

Temporal arteritis (Horton's disease) is a multifocal granulomatous arteritis which affects elderly people. Its prognosis depends upon the risk of blindness. In a retrospective study of 130 patients we paid special attention to the delay in diagnosis and its relation to the occurrence of ophthalmic complications. In 73 patients (56.2%), this delay exceeded 3 months and reached more than one year in 22 of them. It was not influenced by age or sex. In requests for admission, the diagnosis of temporal arteritis was suggested in only 28 of the 130 cases; 17.7% of the patients were blind. There was a significant increase in the occurrence of ophthalmic lesions when the diagnosis was delayed by 2 to 6 months. In 6 cases, blindness had been preceded by transient amaurosis. These findings confirm that temporal arteritis is belatedly diagnosed by practitioners and that blindness could be avoided by an earlier diagnosis.