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International audience; The bacterial epidemiology of bacterascites and spontaneous bacterial peritonitis is evolving. Four hundred and eleven strains isolated from ascites in cirrhotic patients from 5 French hospitals were isolated in 2006 and 2007. Of these, 114 were definitely associated with spontaneous bacterial peritonitis. The proportion of Gram-positive and Gram-negative agents was quite similar, even after excluding coagulase-negative staphylococci, or when considering only definite spontaneous bacterial peritonitis or community-acquired strains. Staphylococci and Escherichia coli were the most frequent pathogens, but enterococci were also involved in nearly 15% of the cases. Among the E. coli, 28% were intermediate or resistant to amoxicillin+clavulanate, 5.3% expressed cephalosporinases or extended beta-lactamases and 17.3% were intermediate or resistant to fluoroquinolones. Resistance to methicillin was observed in 27% of Staphylococcus aureus. Cefotaxime and amoxicillin-clavulanate remained the most effective 'single' agents, however on less than 70% of isolates. Some combinations (such as cefotaxime+amoxicillin) extended coverage to a further 15% of strains. Since inadequate empiric antibiotic therapy is associated with increased mortality, these combinations may be of great interest as first-line treatment, even though they may also lead to the development of antimicrobial resistance. Repeated epidemiological surveys and new clinical trials are thus needed.

International audience; Most secretion pathways in bacteria and eukaryotic cells are challenged by the requirement for their substrate proteins to mature after they traverse a membrane barrier and enter a reactive oxidizing environment. For Gram-positive bacteria, the mechanisms that protect their exported proteins from misoxidation during their post-translocation maturation are poorly understood. To address this, we separated numerous bacterial species according to their tolerance for oxygen and divided their proteomes based on the predicted subcellular localization of their proteins. We then applied a previously established computational approach that utilizes cysteine incorporation patterns in proteins as an indicator of enzymatic systems that may exist in each species. The Sec-dependent exported proteins from aerobic Gram-positive Actinobacteria were found to encode cysteines in an even-biased pattern indicative of a functional disulfide bond formation system. In contrast, aerobic Gram-positive Firmicutes favor the exclusion of cysteines from both their cytoplasmic proteins and their substantially longer exported proteins. Supporting these findings, we show that Firmicutes, but not Actinobacteria, tolerate growth in reductant. We further demonstrate that the actinobacterium Corynebacterium glutamicum possesses disulfide-bonded proteins and two dimeric Dsb-like enzymes that can efficiently catalyze the formation of disulfide bonds. Our results suggest that cysteine exclusion is an important adaptive strategy against the challenges presented by oxidative environments.

International audience; The increased incidence over the past decade of bloodstream infections (BSIs) caused by gram-positive bacteria, particularly methicillin-resistant Staphylococcus aureus, highlights the critical need for a consistent approach to therapy. However, there is currently no international consensus on the diagnosis and management of gram-positive BSIs. The Clinical Consensus Conference on Gram-Positive Bloodstream Infections was convened as a session at the 9th International Symposium on Modern Concepts in Endocarditis and Cardiovascular Infections held in 2007. Participants discussed various aspects of the practical treatment of patients who present with gram-positive BSI, including therapeutic options for patients with BSIs of undefined origin, the selection of appropriate empirical therapy, and treatment of complicated and uncomplicated BSIs. The opinions of participants about these key issues are reflected in this article.