Cerebral perfusion in sepsis

This article is one of ten reviews selected from the Yearbook of Intensive Care and Emergency Medicine 2010 (Springer Verlag) and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/yearbook. Further information about the Yearbook of Intensive Care and Emergency Medicine is available from http://www.springer.com/series/2855

Burkholderia kirstenboschensis sp. nov. nodulates papilionoid legumes indigenous to South Africa

Despite the diversity of Burkholderia species known to nodulate legumes in introduced and native regions, relatively few taxa have been formally described. For example, the Cape Floristic Region of South Africa is thought to represent one of the major centres of diversity for the rhizobial members of Burkholderia, yet only five species have been described from legumes occurring in this region and numerous are still awaiting taxonomic treatment. Here, we investigated the taxonomic status of 12 South African root-nodulating Burkholderia isolates from native papilionoid legumes (Hypocalyptus coluteoides, H. oxalidifolius, H. sophoroides and Virgilia oroboides). Analysis of four gene regions (16S rRNA, recA, atpD and rpoB) revealed that the isolates represent a genealogically unique and exclusive assemblage within the genus. Its distinctness was supported by all other aspects of the polyphasic approach utilized, including the genome-based criteria DNA−DNA hybridization (≥70.9%) and average nucleotide identities (≥96%). We accordingly propose the name B. kirstenboschensis sp. nov. for this taxon with isolate Kb15T (=LMG 28727T; =SARC 695T) as its type strain. Our data showed that intraspecific genome size differences (≥0.81 Mb) and the occurrence of large DNA regions that are apparently unique to single individuals (16−23% of an isolate's genome) can significantly limit the value of data obtained from DNA−DNA hybridization experiments. Substitution of DNA−DNA hybridization with whole genome sequencing as a prerequisite for the description of Burkholderia species will undoubtedly speed up the pace at which their diversity are documented, especially in hyperdiverse regions such as the Cape Floristic Region.South African National Research Foundation (NRF) and the Department of Science and Technology.http://www.elsevier.de/syapm2016-12-31hb201

Increasing arterial blood pressure with norepinephrine does not improve microcirculatory blood flow: a prospective study

Introduction Our goal was to assess the effects of titration of a norepinephrine infusion to increasing levels of mean arterial pressure (MAP) on sublingual microcirculation. Methods Twenty septic shock patients were prospectively studied in two teaching intensive care units. The patients were mechanically ventilated and required norepinephrine to maintain a mean arterial pressure (MAP) of 65 mmHg. We measured systemic hemodynamics, oxygen transport and consumption (DO2 and VO2), lactate, albumin-corrected anion gap, and gastric intramucosal-arterial PCO2 difference (Delta PCO2). Sublingual microcirculation was evaluated by sidestream darkfield (SDF) imaging. After basal measurements at a MAP of 65 mmHg, norepinephrine was titrated to reach a MAP of 75 mmHg, and then to 85 mmHg. Data were analyzed using repeated measurements ANOVA and Dunnett test. Linear trends between the different variables and increasing levels of MAP were calculated. Results Increasing doses of norepinephrine reached the target values of MAP. The cardiac index, pulmonary pressures, systemic vascular resistance, and left and right ventricular stroke work indexes increased as norepinephrine infusion was augmented. Heart rate, DO2 and VO2, lactate, albumin-corrected anion gap, and Delta PCO2 remained unchanged. There were no changes in sublingual capillary microvascular flow index (2.1 +/- 0.7, 2.2 +/- 0.7, 2.0 +/- 0.8) and the percent of perfused capillaries (72 +/- 26, 71 +/- 27, 67 +/- 32%) for MAP values of 65, 75, and 85 mmHg, respectively. There was, however, a trend to decreased capillary perfused density (18 +/- 10,17 +/- 10,14 +/- 2 vessels/mm(2), respectively, ANOVA P = 0.09, linear trend P = 0.045). In addition, the changes of perfused capillary density at increasing MAP were inversely correlated with the basal perfused capillary density (R-2 = 0.95, P < 0.0001). Conclusions Patients with septic shock showed severe sublingual microcirculatory alterations that failed to improve with the increases in MAP with norepinephrine. Nevertheless, there was a considerable interindividual variation. Our results suggest that the increase in MAP above 65 mmHg is not an adequate approach to improve microcirculatory perfusion and might be harmful in some patient

Paraburkholderia strydomiana sp. nov. and Paraburkholderia steynii sp. nov.: rhizobial symbionts of the fynbos legume Hypocalyptus sophoroides

Please read abstract in the article.Supplementary Table S1. GenBank accession numbers for the sequences generated in this study as well as for the 12 Paraburkholderia isolates being investigatedSupplementary Table S2. Metabolic, biochemical and fatty acid properties according to Biolog GN2, API 20NE tests and as determined by gas chromatography. Results include all the strains of the two novel species, except for the fatty acid analysis which was only performed on the respective type strains.Supplementary Table S3. Percentages of genomes analysed during ANI analyses (number of nucleotides/ number of fragments).Supplementary Table S4. Comparative genome characteristics of P. strydomiana sp. nov., P. steynii sp. nov. and their closest phylogenetic neighbours.Supplementary FiguresThis study was funded by the National Research Fund (NRF). University of Pretoria DNA sequencing facility for Sanger sequencing, as well as the library building for Ion Torrent Proton Sequencing.http://link.springer.com/journal/104822020-09-01hj2019BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog