Sortase A Substrate Specificity in GBS Pilus 2a Cell Wall Anchoring

Streptococcus agalactiae, also referred to as Group B Streptococcus (GBS), is one of the most common causes of life-threatening bacterial infections in infants. In recent years cell surface pili have been identified in several Gram-positive bacteria, including GBS, as important virulence factors and promising vaccine candidates. In GBS, three structurally distinct types of pili have been discovered (pilus 1, 2a and 2b), whose structural subunits are assembled in high-molecular weight polymers by specific class C sortases. In addition, the highly conserved housekeeping sortase A (SrtA), whose main role is to link surface proteins to bacterial cell wall peptidoglycan by a transpeptidation reaction, is also involved in pili cell wall anchoring in many bacteria. Through in vivo mutagenesis, we demonstrate that the LPXTG sorting signal of the minor ancillary protein (AP2) is essential for pilus 2a anchoring. We successfully produced a highly purified recombinant SrtA (SrtAΔN40) able to specifically hydrolyze the sorting signal of pilus 2a minor ancillary protein (AP2-2a) and catalyze in vitro the transpeptidation reaction between peptidoglycan analogues and the LPXTG motif, using both synthetic fluorescent peptides and recombinant proteins. By contrast, SrtAΔN40 does not catalyze the transpeptidation reaction with substrate-peptides mimicking sorting signals of the other pilus 2a subunits (the backbone protein and the major ancillary protein). Thus, our results add further insight into the proposed model of GBS pilus 2a assembly, in which SrtA is required for pili cell wall covalent attachment, acting exclusively on the minor accessory pilin, representing the terminal subunit located at the base of the pilus

Supramolecular Organization of the Repetitive Backbone Unit of the Streptococcus pneumoniae Pilus

Streptococcus pneumoniae, like many other Gram-positive bacteria, assembles long filamentous pili on their surface through which they adhere to host cells. Pneumococcal pili are formed by a backbone, consisting of the repetition of the major component RrgB, and two accessory proteins (RrgA and RrgC). Here we reconstruct by transmission electron microscopy and single particle image reconstruction method the three dimensional arrangement of two neighbouring RrgB molecules, which represent the minimal repetitive structural domain of the native pilus. The crystal structure of the D2-D4 domains of RrgB was solved at 1.6 Å resolution. Rigid-body fitting of the X-ray coordinates into the electron density map enabled us to define the arrangement of the backbone subunits into the S. pneumoniae native pilus. The quantitative fitting provide evidence that the pneumococcal pilus consists uniquely of RrgB monomers assembled in a head-to-tail organization. The presence of short intra-subunit linker regions connecting neighbouring domains provides the molecular basis for the intrinsic pilus flexibility

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Echographie doppler des doigts dans la polyarthrite rhumatoïde et du rhumatisme psoriasique

Objectifs : Notre étude a pour objectifs d'évaluer l'apport de l'échographie doppler dans l'atteinte digitale au cours de la polyarthrite rhumatoïde et du rhumatisme psoriasique et de rechercher des signes échographiques évocateurs de RP. Patients-Matériels-Méthodes : Notre étude regroupe des patients porteurs de PR ou de RP définis. Chaque patient présente une (ou plusieurs) atteinte digitale avec au moins une arthralgie, selon un mode aiguë ou chronique. L'étude comporte un examen clinique précis du doigt, le dosage de la CRP, une radiographie des mains de face, une échographie-doppler du doigt retenu. Pour certains, l'échographie a été couplée à l'injection d'un agent de contraste échographique. Nous avons utilisé les stades radiologiques de Steinbrocker (St.) et les critères radiologiques des doigts et des orteils de Fournié (CRDO). Résultats : 34 patients sont inclus ( 17 PR et 17 RP) soit 40 doigts. L'examen clinique note chez nos PR, 23 fluxions articulaires et 19 fluxions articulaires parmi les RP ; 10 ténosynovites des fléchisseurs dans le groupe PR et 8 ténosynovites des fléchisseurs chez les RP. A la lecture des clichés radiologiques nous comptabilisons chez nos PR : 2 St. 1 ; 12 St. 2 ; 6 St. 3 ; 3 St. 4 ; 4 PR ont une radiographie normale. Dans le groupe RP : 8 St. 2 ; 2 St. 3 ; 3 CRDO 1 ; 2 CRDO 2 ; 2 CRDO 3 ; 12 CRDO 4 ; 1 CRDO 5 ; 5 RP ont une radiologie normale. Avec l'échographie, nous avons détecté 29 synovites dans le groupe PR et 21 synovites dans le groupe RP ; 11 ténosynovites des fléchisseurs associé pour deux d'entre elles à une tendinite, et 4 ténosynovites des extenseurs chez les PR ; 3 ténosynovites des fléchisseurs dans le groupe RP. L'étude doppler notait une hypervascularisation localisée dans 8 synovites chez 5 PR et dans 7 synovites chez 7RP. L'étude des contours osseux par échographie distinguait 22 érosions articulaires au sein des PR et 15 érosions parmi les RP. Chez les RP nous recueillons par ailleurs des signes d'enthèsite : irrégularités d'insertion du tendon fléchisseur sur P3, irrégularités capsulaires, périostites juxta-articulaires, anomalie du signal doppler de la pulpe, de la région unguéale. Conclusion : L'échographie doppler s'avère plus sensible pour le dépistage des synovites et des érosions osseuses dans ces deux RIC. Elle révèle des signes d'enthèsite, au niveau des doigts de RP exclusivement, parfois associés à des synovites : ceci confirme le double tropisme du RP : synovial et enthèsique.TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE3-BU Santé-Allées (315552109) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Le Néolithique final Couronnien en Basse-Provence occidentale, de Max Escalon de Fonton au Projet Collectif de Recherche de l’UMR 6636 (1947-2004)

International audienc

Le Néolithique final Couronnien en Basse-Provence occidentale, de Max Escalon de Fonton au Projet Collectif de Recherche de l’UMR 6636 (1947-2004)

International audienc

Le site néolithique final de Ponteau-Gare à Martigues (Bouches-du-Rhône), rapport de synthèse de fouille archéologique programmée triennale 2007, 2008, 2009

Aix-en-Provence, Service archéologique de la Ville de Martigues / umr 6636 "LAMPEA" / DRAC PACA - SR