Angiography after Out-of-Hospital Cardiac Arrest without ST-Segment Elevation.

BACKGROUND: Myocardial infarction is a frequent cause of out-of-hospital cardiac arrest. However, the benefits of early coronary angiography and revascularization in resuscitated patients without electrocardiographic evidence of ST-segment elevation are unclear. METHODS: In this multicenter trial, we randomly assigned 554 patients with successfully resuscitated out-of-hospital cardiac arrest of possible coronary origin to undergo either immediate coronary angiography (immediate-angiography group) or initial intensive care assessment with delayed or selective angiography (delayed-angiography group). All the patients had no evidence of ST-segment elevation on postresuscitation electrocardiography. The primary end point was death from any cause at 30 days. Secondary end points included a composite of death from any cause or severe neurologic deficit at 30 days. RESULTS: A total of 530 of 554 patients (95.7%) were included in the primary analysis. At 30 days, 143 of 265 patients (54.0%) in the immediate-angiography group and 122 of 265 patients (46.0%) in the delayed-angiography group had died (hazard ratio, 1.28; 95% confidence interval [CI], 1.00 to 1.63; P = 0.06). The composite of death or severe neurologic deficit occurred more frequently in the immediate-angiography group (in 164 of 255 patients [64.3%]) than in the delayed-angiography group (in 138 of 248 patients [55.6%]), for a relative risk of 1.16 (95% CI, 1.00 to 1.34). Values for peak troponin release and for the incidence of moderate or severe bleeding, stroke, and renal-replacement therapy were similar in the two groups. CONCLUSIONS: Among patients with resuscitated out-of-hospital cardiac arrest without ST-segment elevation, a strategy of performing immediate angiography provided no benefit over a delayed or selective strategy with respect to the 30-day risk of death from any cause. (Funded by the German Center for Cardiovascular Research; TOMAHAWK ClinicalTrials.gov number, NCT02750462.).

SHMT2 inhibition disrupts the TCF3 transcriptional survival program in Burkitt lymphoma.

Burkitt lymphoma (BL) is an aggressive lymphoma type that is currently treated by intensive chemoimmunotherapy. Despite the favorable clinical outcome for most patients with BL, chemotherapy-related toxicity and disease relapse remain major clinical challenges, emphasizing the need for innovative therapies. Using genome-scale CRISPR-Cas9 screens, we identified B-cell receptor (BCR) signaling, specific transcriptional regulators, and one-carbon metabolism as vulnerabilities in BL. We focused on serine hydroxymethyltransferase 2 (SHMT2), a key enzyme in one-carbon metabolism. Inhibition of SHMT2 by either knockdown or pharmacological compounds induced anti-BL effects in vitro and in vivo. Mechanistically, SHMT2 inhibition led to a significant reduction of intracellular glycine and formate levels, which inhibited the mTOR pathway and thereby triggered autophagic degradation of the oncogenic transcription factor TCF3. Consequently, this led to a collapse of tonic BCR signaling, which is controlled by TCF3 and is essential for BL cell survival. In terms of clinical translation, we also identified drugs such as methotrexate that synergized with SHMT inhibitors. Overall, our study has uncovered the dependency landscape in BL, identified and validated SHMT2 as a drug target, and revealed a mechanistic link between SHMT2 and the transcriptional master regulator TCF3, opening up new perspectives for innovative therapies.

Checkpoint inhibition enhances cell contacts between CD4+ T cells and Hodgkin-Reed-Sternberg cells of classic Hodgkin lymphoma.

Although checkpoint molecules like CTLA-4 and PD1 have been described several years ago, checkpoint inhibitors such as Nivolumab (an anti-PD-1 antibody) have only recently been used to treat classic Hodgkin lymphoma (cHL). Several studies have shown convincing therapeutic effects of Nivolumab in cHL. However, the mechanism of action of Nivolumab in cHL is not fully understood. The aim of this study was to monitor changes in cell motility and cell contacts after administration of Nivolumab to an in vitro model of cHL as well as to native hyperplastic lymphoid tissue and native human tissue from cHL. In both tissue and in vitro, CD4+, CD8+, CD30+ and CD20+ cell velocities were unchanged after Nivolumab incubation. In contrast, in primary cHL tissue, the duration of cell contacts between CD4+ T cells and HRS cells was significantly increased after 5 h Nivolumab treatment, and the number of contacts with HRS cells was also slightly increased for CD4+ T cells (not significant), suggesting that CD4+ T cells in particular contribute to the cytotoxicity observed as a result of Nivolumab therapy. There was no change in the duration of cell contacts in the hyperplastic lymphoid tissue after Nivolumab incubation. In conclusion, we show here for the first time by imaging of native lymphoma tissue an enhanced interaction of CD4+ T cells and HRS cells in cHL after Nivolumab administration.

A multiprotein supercomplex controlling oncogenic signalling in lymphoma.

B cell receptor (BCR) signalling has emerged as a therapeutic target in B cell lymphomas, but inhibiting this pathway in diffuse large B cell lymphoma (DLBCL) has benefited only a subset of patients1. Gene expression profiling identified two major subtypes of DLBCL, known as germinal centre B cell-like and activated B cell-like (ABC)2,3, that show poor outcomes after immunochemotherapy in ABC. Autoantigens drive BCR-dependent activation of NF-κB in ABC DLBCL through a kinase signalling cascade of SYK, BTK and PKCß to promote the assembly of the CARD11-BCL10-MALT1 adaptor complex, which recruits and activates IκB kinase4-6. Genome sequencing revealed gain-of-function mutations that target the CD79A and CD79B BCR subunits and the Toll-like receptor signalling adaptor MYD885,7, with MYD88(L265P) being the most prevalent isoform. In a clinical trial, the BTK inhibitor ibrutinib produced responses in 37% of cases of ABC1. The most striking response rate (80%) was observed in tumours with both CD79B and MYD88(L265P) mutations, but how these mutations cooperate to promote dependence on BCR signalling remains unclear. Here we used genome-wide CRISPR-Cas9 screening and functional proteomics to determine the molecular basis of exceptional clinical responses to ibrutinib. We discovered a new mode of oncogenic BCR signalling in ibrutinib-responsive cell lines and biopsies, coordinated by a multiprotein supercomplex formed by MYD88, TLR9 and the BCR (hereafter termed the My-T-BCR supercomplex). The My-T-BCR supercomplex co-localizes with mTOR on endolysosomes, where it drives pro-survival NF-κB and mTOR signalling. Inhibitors of BCR and mTOR signalling cooperatively decreased the formation and function of the My-T-BCR supercomplex, providing mechanistic insight into their synergistic toxicity for My-T-BCR+ DLBCL cells. My-T-BCR supercomplexes characterized ibrutinib-responsive malignancies and distinguished ibrutinib responders from non-responders. Our data provide a framework for the rational design of oncogenic signalling inhibitors in molecularly defined subsets of DLBCL.

Malignant pirates of the immune system.

At great human cost, cancer is the largest genetic experiment ever conducted. This review highlights how lymphoid malignancies have genetically perverted normal immune signaling and regulatory mechanisms for their selfish oncogenic goals of unlimited proliferation, perpetual survival and evasion of the immune response.

Molecular Subgroups of Diffuse Large B Cell Lymphoma: Biology and Implications for Clinical Practice.

PURPOSE OF REVIEW: Genomic analyses have immensely advanced our conception of the heterogeneity of diffuse large B cell lymphoma (DLBCL), resulting in subgroups with distinct molecular profiles. In this review, we summarize our current knowledge of the biology of DLBCL complexity and discuss the potential implications for precision medicine. RECENT FINDINGS: During the last two decades, gene expression profiling, copy number analysis, and high throughput sequencing enabled the identification of molecular subclasses of DLBCL that are biologically and clinically meaningful. The resulting classifications provided novel prospects of diagnosis, prognostication, and therapeutic strategies for this aggressive disease. The molecular characterization of DLBCL offers unprecedented insights into the biology of these lymphomas that can guide precision medicine. The knowledge of the molecular setup of an individual DLBCL patients enables prognostication of patients and will be useful to stratify patients in clinical trials. Future direction should focus to implement the molecular classifications of DLBCL in the clinical practice to evaluate their significance and scope using real-world data.

Genetics and Pathogenesis of Diffuse Large B-Cell Lymphoma.

BACKGROUND: Diffuse large B-cell lymphomas (DLBCLs) are phenotypically and genetically heterogeneous. Gene-expression profiling has identified subgroups of DLBCL (activated B-cell-like [ABC], germinal-center B-cell-like [GCB], and unclassified) according to cell of origin that are associated with a differential response to chemotherapy and targeted agents. We sought to extend these findings by identifying genetic subtypes of DLBCL based on shared genomic abnormalities and to uncover therapeutic vulnerabilities based on tumor genetics. METHODS: We studied 574 DLBCL biopsy samples using exome and transcriptome sequencing, array-based DNA copy-number analysis, and targeted amplicon resequencing of 372 genes to identify genes with recurrent aberrations. We developed and implemented an algorithm to discover genetic subtypes based on the co-occurrence of genetic alterations. RESULTS: We identified four prominent genetic subtypes in DLBCL, termed MCD (based on the co-occurrence of MYD88L265P and CD79B mutations), BN2 (based on BCL6 fusions and NOTCH2 mutations), N1 (based on NOTCH1 mutations), and EZB (based on EZH2 mutations and BCL2 translocations). Genetic aberrations in multiple genes distinguished each genetic subtype from other DLBCLs. These subtypes differed phenotypically, as judged by differences in gene-expression signatures and responses to immunochemotherapy, with favorable survival in the BN2 and EZB subtypes and inferior outcomes in the MCD and N1 subtypes. Analysis of genetic pathways suggested that MCD and BN2 DLBCLs rely on "chronic active" B-cell receptor signaling that is amenable to therapeutic inhibition. CONCLUSIONS: We uncovered genetic subtypes of DLBCL with distinct genotypic, epigenetic, and clinical characteristics, providing a potential nosology for precision-medicine strategies in DLBCL. (Funded by the Intramural Research Program of the National Institutes of Health and others.).

Genome-wide discovery of somatic coding and noncoding mutations in pediatric endemic and sporadic Burkitt lymphoma.

Although generally curable with intensive chemotherapy in resource-rich settings, Burkitt lymphoma (BL) remains a deadly disease in older patients and in sub-Saharan Africa. Epstein-Barr virus (EBV) positivity is a feature in more than 90% of cases in malaria-endemic regions, and up to 30% elsewhere. However, the molecular features of BL have not been comprehensively evaluated when taking into account tumor EBV status or geographic origin. Through an integrative analysis of whole-genome and transcriptome data, we show a striking genome-wide increase in aberrant somatic hypermutation in EBV-positive tumors, supporting a link between EBV and activation-induced cytidine deaminase (AICDA) activity. In addition to identifying novel candidate BL genes such as SIN3A, USP7, and CHD8, we demonstrate that EBV-positive tumors had significantly fewer driver mutations, especially among genes with roles in apoptosis. We also found immunoglobulin variable region genes that were disproportionally used to encode clonal B-cell receptors (BCRs) in the tumors. These include IGHV4-34, known to produce autoreactive antibodies, and IGKV3-20, a feature described in other B-cell malignancies but not yet in BL. Our results suggest that tumor EBV status defines a specific BL phenotype irrespective of geographic origin, with particular molecular properties and distinct pathogenic mechanisms. The novel mutation patterns identified here imply rational use of DNA-damaging chemotherapy in some patients with BL and targeted agents such as the CDK4/6 inhibitor palbociclib in others, whereas the importance of BCR signaling in BL strengthens the potential benefit of inhibitors for PI3K, Syk, and Src family kinases among these patients.

Loss of signalling via Gα13 in germinal centre B-cell-derived lymphoma.

Germinal centre B-cell-like diffuse large B-cell lymphoma (GCB-DLBCL) is a common malignancy, yet the signalling pathways that are deregulated and the factors leading to its systemic dissemination are poorly defined. Work in mice showed that sphingosine-1-phosphate receptor-2 (S1PR2), a Gα12 and Gα13 coupled receptor, promotes growth regulation and local confinement of germinal centre B cells. Recent deep sequencing studies of GCB-DLBCL have revealed mutations in many genes in this cancer, including in GNA13 (encoding Gα13) and S1PR2 (refs 5,6, 7). Here we show, using in vitro and in vivo assays, that GCB-DLBCL-associated mutations occurring in S1PR2 frequently disrupt the receptor's Akt and migration inhibitory functions. Gα13-deficient mouse germinal centre B cells and human GCB-DLBCL cells were unable to suppress pAkt and migration in response to S1P, and Gα13-deficient mice developed germinal centre B-cell-derived lymphoma. Germinal centre B cells, unlike most lymphocytes, are tightly confined in lymphoid organs and do not recirculate. Remarkably, deficiency in Gα13, but not S1PR2, led to germinal centre B-cell dissemination into lymph and blood. GCB-DLBCL cell lines frequently carried mutations in the Gα13 effector ARHGEF1, and Arhgef1 deficiency also led to germinal centre B-cell dissemination. The incomplete phenocopy of Gα13- and S1PR2 deficiency led us to discover that P2RY8, an orphan receptor that is mutated in GCB-DLBCL and another germinal centre B-cell-derived malignancy, Burkitt's lymphoma, also represses germinal centre B-cell growth and promotes confinement via Gα13. These findings identify a Gα13-dependent pathway that exerts dual actions in suppressing growth and blocking dissemination of germinal centre B cells that is frequently disrupted in germinal centre B-cell-derived lymphoma.

Immediate unselected coronary angiography versus delayed triage in survivors of out-of-hospital cardiac arrest without ST-segment elevation: Design and rationale of the TOMAHAWK trial.

Patients experiencing out-of-hospital cardiac arrest (OHCA) without ST-segment elevation are a heterogenic group with a variety of underlying causes. Up to one-third of patients display a significant coronary lesion compatible with myocardial infarction as OHCA trigger. There are no randomized data on patient selection and timing of invasive coronary angiography after admission. METHODS AND RESULTS: The TOMAHAWK trial randomly assigns 558 patients with return of spontaneous circulation after OHCA with no obvious extracardiac origin of cardiac arrest and no ST-segment elevation/left bundle-branch block on postresuscitation electrocardiogram to either immediate coronary angiography or initial intensive care assessment with delayed/selective angiography in a 1:1 ratio. The primary end point is 30-day all-cause mortality. Secondary analyses will be performed with respect to initial rhythm, electrocardiographic patterns, myocardial infarction as underlying cause, neurological outcome, as well as clinical and laboratory markers. Clinical follow-up will be performed at 6 and 12 months. Safety end points include bleeding and stroke. CONCLUSION: The TOMAHAWK trial will address the unresolved issue of timing and general indication of angiography after OHCA without ST-segment elevation.

Regulation of normal B-cell differentiation and malignant B-cell survival by OCT2.

The requirement for the B-cell transcription factor OCT2 (octamer-binding protein 2, encoded by Pou2f2) in germinal center B cells has proved controversial. Here, we report that germinal center B cells are formed normally after depletion of OCT2 in a conditional knockout mouse, but their proliferation is reduced and in vivo differentiation to antibody-secreting plasma cells is blocked. This finding led us to examine the role of OCT2 in germinal center-derived lymphomas. shRNA knockdown showed that almost all diffuse large B-cell lymphoma (DLBCL) cell lines are addicted to the expression of OCT2 and its coactivator OCA-B. Genome-wide chromatin immunoprecipitation (ChIP) analysis and gene-expression profiling revealed the broad transcriptional program regulated by OCT2 that includes the expression of STAT3, IL-10, ELL2, XBP1, MYC, TERT, and ADA. Importantly, genetic alteration of OCT2 is not a requirement for cellular addiction in DLBCL. However, we detected amplifications of the POU2F2 locus in DLBCL tumor biopsies and a recurrent mutation of threonine 223 in the DNA-binding domain of OCT2. This neomorphic mutation subtly alters the DNA-binding preference of OCT2, leading to the transactivation of noncanonical target genes including HIF1a and FCRL3 Finally, by introducing mutations designed to disrupt the OCT2-OCA-B interface, we reveal a requirement for this protein-protein interface that ultimately might be exploited therapeutically. Our findings, combined with the predominantly B-cell-restricted expression of OCT2 and the absence of a systemic phenotype in our knockout mice, suggest that an OCT2-targeted therapeutic strategy would be efficacious in both major subtypes of DLBCL while avoiding systemic toxicity.

Burkitt lymphoma pathogenesis and therapeutic targets from structural and functional genomics.

Burkitt's lymphoma (BL) can often be cured by intensive chemotherapy, but the toxicity of such therapy precludes its use in the elderly and in patients with endemic BL in developing countries, necessitating new strategies. The normal germinal centre B cell is the presumed cell of origin for both BL and diffuse large B-cell lymphoma (DLBCL), yet gene expression analysis suggests that these malignancies may use different oncogenic pathways. BL is subdivided into a sporadic subtype that is diagnosed in developed countries, the Epstein-Barr-virus-associated endemic subtype, and an HIV-associated subtype, but it is unclear whether these subtypes use similar or divergent oncogenic mechanisms. Here we used high-throughput RNA sequencing and RNA interference screening to discover essential regulatory pathways in BL that cooperate with MYC, the defining oncogene of this cancer. In 70% of sporadic BL cases, mutations affecting the transcription factor TCF3 (E2A) or its negative regulator ID3 fostered TCF3 dependency. TCF3 activated the pro-survival phosphatidylinositol-3-OH kinase pathway in BL, in part by augmenting tonic B-cell receptor signalling. In 38% of sporadic BL cases, oncogenic CCND3 mutations produced highly stable cyclin D3 isoforms that drive cell cycle progression. These findings suggest opportunities to improve therapy for patients with BL.

Survival of human lymphoma cells requires B-cell receptor engagement by self-antigens.

The activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) relies on chronic active B-cell receptor (BCR) signaling. BCR pathway inhibitors induce remissions in a subset of ABC DLBCL patients. BCR microclusters on the surface of ABC cells resemble those generated following antigen engagement of normal B cells. We speculated that binding of lymphoma BCRs to self-antigens initiates and maintains chronic active BCR signaling in ABC DLBCL. To assess whether antigenic engagement of the BCR is required for the ongoing survival of ABC cells, we developed isogenic ABC cells that differed solely with respect to the IgH V region of their BCRs. In competitive assays with wild-type cells, substitution of a heterologous V region impaired the survival of three ABC lines. The viability of one VH4-34(+) ABC line and the ability of its BCR to bind to its own cell surface depended on V region residues that mediate the intrinsic autoreactivity of VH4-34 to self-glycoproteins. The BCR of another ABC line reacted with self-antigens in apoptotic debris, and the survival of a third ABC line was sustained by reactivity of its BCR to an idiotypic epitope in its own V region. Hence, a diverse set of self-antigens is responsible for maintaining the malignant survival of ABC DLBCL cells. IgH V regions used by the BCRs of ABC DLBCL biopsy samples varied in their ability to sustain survival of these ABC lines, suggesting a screening procedure to identify patients who might benefit from BCR pathway inhibition.

Bioactive pyrrole alkaloids isolated from the Red Sea: marine sponge Stylissa carteri.

Fifteen pyrrole alkaloids were isolated from the Red Sea marine sponge Stylissa carteri and investigated for their biological activities. Four of them were dibrominated [(+) dibromophakelline, Z-3-bromohymenialdisine, (±) ageliferin and 3,4-dibromo-1H-pyrrole-2-carbamide], nine compounds were monobrominated [(-) clathramide C, agelongine, (+) manzacidin A, (-) 3-bromomanzacidin D, Z-spongiacidin D, Z-hymenialdisine, 2-debromostevensine, 2-bromoaldisine and 4-bromo-1H-pyrrole-2-carbamide)] and finally, two compounds were non-brominated derivatives viz., E-debromohymenialdisine and aldisine. The structure elucidations of isolated compounds were based on 1D & 2D NMR spectroscopic and MS studies, as well as by comparison with literature. In-vitro, Z-spongiacidin D exhibited a moderate activity on (ARK5, CDK2-CycA, CDK4/CycD1, VEGF-R2, SAK and PDGFR-beta) protein kinases. Moreover, Z-3-bromohymenialdisine showed nearly similar pattern. Furthermore, Z-hymenialdisine displayed a moderate effect on (ARK5 & VEGF-R2) and (-) clathramide C showed a moderate activity on AURORA-A protein kinases. While, agelongine, (+) manzacidin A, E-debromohymenialdisine and 3,4-dibromo-1H-pyrrole-2-carbamide demonstrated only marginal inhibitory activities. The cytotoxicity study was evaluated in two different cell lines. The most effective secondary metabolites were (+) dibromophakelline and Z-3-bromohymenialdisine on L5178Y. Finally, Z-hymenialdisine, Z-3-bromohymenialdisine and (±) ageliferin exhibited the highest cytotoxic activity on HCT116. No report about inhibition of AURORA-A and B by hymenialdisine/hymenialdisine analogs existed and no reported toxicity of ageliferin existed in literature.

Oncogenically active MYD88 mutations in human lymphoma.

The activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) remains the least curable form of this malignancy despite recent advances in therapy. Constitutive nuclear factor (NF)-κB and JAK kinase signalling promotes malignant cell survival in these lymphomas, but the genetic basis for this signalling is incompletely understood. Here we describe the dependence of ABC DLBCLs on MYD88, an adaptor protein that mediates toll and interleukin (IL)-1 receptor signalling, and the discovery of highly recurrent oncogenic mutations affecting MYD88 in ABC DLBCL tumours. RNA interference screening revealed that MYD88 and the associated kinases IRAK1 and IRAK4 are essential for ABC DLBCL survival. High-throughput RNA resequencing uncovered MYD88 mutations in ABC DLBCL lines. Notably, 29% of ABC DLBCL tumours harboured the same amino acid substitution, L265P, in the MYD88 Toll/IL-1 receptor (TIR) domain at an evolutionarily invariant residue in its hydrophobic core. This mutation was rare or absent in other DLBCL subtypes and Burkitt's lymphoma, but was observed in 9% of mucosa-associated lymphoid tissue lymphomas. At a lower frequency, additional mutations were observed in the MYD88 TIR domain, occurring in both the ABC and germinal centre B-cell-like (GCB) DLBCL subtypes. Survival of ABC DLBCL cells bearing the L265P mutation was sustained by the mutant but not the wild-type MYD88 isoform, demonstrating that L265P is a gain-of-function driver mutation. The L265P mutant promoted cell survival by spontaneously assembling a protein complex containing IRAK1 and IRAK4, leading to IRAK4 kinase activity, IRAK1 phosphorylation, NF-κB signalling, JAK kinase activation of STAT3, and secretion of IL-6, IL-10 and interferon-ß. Hence, the MYD88 signalling pathway is integral to the pathogenesis of ABC DLBCL, supporting the development of inhibitors of IRAK4 kinase and other components of this pathway for the treatment of tumours bearing oncogenic MYD88 mutations.

Novel IGH and MYC Translocation Partners in Diffuse Large B-Cell Lymphomas.

Chromosomal translocations involving an immunoglobulin (IG) locus and a proto-oncogene play a major role in diffuse large B-cell lymphoma (DLBCL) pathogenesis. Recurrent IG translocation partners in DLBCL are the BCL6, BCL2, and MYC genes, but other rare translocation partners are also known. We studied 20 DLBCL with fluorescence in situ hybridization-based evidence for IG heavy chain (IGH) locus-associated translocations not involving BCL6, BCL2, MALT1, or MYC by long distance inverse PCR to identify the translocation partners. Moreover, we studied eight DLBCL with MYC translocations not involving IG or known non-IG loci as translocation partner to search for novel MYC translocations. We identified three novel IGH-associated translocations. Chromosomal breakpoints involved the IMMP2L gene in 7q31, the BCAS2 gene in 1p13, and the PVRL2 gene in 19q13. The latter gene, which is recurrently translocated in T-cell lymphomas, is significantly higher expressed in the biopsy with the translocation compared to cases without this genetic aberration, indicating a pathogenetic role of PVRL2 also in DLBCL. In one case with a MYC break we obtained a novel MYC-SOCS1 translocation representing an unusual translocation of a proto-oncogene with a tumor suppressor gene. Indeed, we demonstrate that the oncogene was deregulated and the tumor suppressor gene inactivated. As both genes undergo aberrant somatic hypermutation in the region of the chromosomal breakpoints, this translocation likely happened as a byproduct of the hypermutation process. Overall, our study suggests that chromosomal translocations in DLBCL are more heterogeneous than previously known. © 2016 Wiley Periodicals, Inc.

Identification of regions important for resistance and signalling within the antimicrobial peptide transporter BceAB of Bacillus subtilis.

In the low-G+C-content Gram-positive bacteria, resistance to antimicrobial peptides is often mediated by so-called resistance modules. These consist of a two-component system and an ATP-binding cassette transporter and are characterized by an unusual mode of signal transduction where the transporter acts as a sensor of antimicrobial peptides, because the histidine kinase alone cannot detect the substrates directly. Thus, the transporters fulfill a dual function as sensors and detoxification systems to confer resistance, but the mechanistic details of these processes are unknown. The paradigm and best-understood example for this is the BceRS-BceAB module of Bacillus subtilis, which mediates resistance to bacitracin, mersacidin, and actagardine. Using a random mutagenesis approach, we here show that mutations that affect specific functions of the transporter BceAB are primarily found in the C-terminal region of the permease, BceB, particularly in the eighth transmembrane helix. Further, we show that while signaling and resistance are functionally interconnected, several mutations could be identified that strongly affected one activity of the transporter but had only minor effects on the other. Thus, a partial genetic separation of the two properties could be achieved by single amino acid replacements, providing first insights into the signaling mechanism of these unusual modules.

Quality of blood culture testing - a survey in intensive care units and microbiological laboratories across four European countries.

INTRODUCTION: Blood culture (BC) testing before initiation of antimicrobial therapy is recommended as a standard of care in international sepsis guidelines and has been shown to reduce intensive care unit (ICU) stay, antibiotic use, and costs in hospitalized patients. Whereas microbiological laboratory practice has been highly standardized, shortfalls in the preanalytic procedures in the ICU (that is indication, time-to-incubation, blood volume and numbers of BC sets) have a significant effect on the diagnostic yield. The objective of this study was to gain insights into current practices regarding BC testing in intensive care units. METHODS: Qualitative survey, data collection by 138 semi-structured telephone interviews in four European countries (Italy, UK, France and Germany) between September and November 2009 in 79 clinical microbiology laboratories (LABs) and 59 ICUs. RESULTS: Whereas BC testing is expected to remain the gold standard for sepsis diagnostics in all countries, there are substantial differences regarding preanalytic procedures. The decision to launch BC testing is carried out by physicians vs. ICU nurses in the UK in 92 vs. 8%, in France in 75 vs. 25%, in Italy in 88 vs. 12% and in Germany in 92 vs. 8%. Physicians vs. nurses collect BCs in the UK in 77 vs. 23%, in France in 0 vs. 100%, in Italy in 6 vs. 94% and in Germany in 54 vs. 46%. The mean time from blood collection to incubation in the UK is 2 h, in France 3 h, in Italy 4 h, but 20 h in German remote LABs (2 h in in-house LABs), due to the large number of remote nonresident microbiological laboratories in Germany. There were major differences between the perception of the quality of BC testing between ICUs and LABs. Among German ICU respondents, 62% reported that they have no problems with BC testing, 15% reported time constraints, 15% cost pressure, and only 8% too long time to incubation. However, the corresponding LABs of these German ICUs reported too many false positive results due to preanalytical contaminations (49%), insufficient numbers of incoming BC sets (47%), long transportation time (41%) or cost pressure (18%). CONCLUSIONS: There are considerable differences in the quality of BC testing across European countries. In Germany, time to incubation is a considerable problem due to the increasing number of remote LABs. This is a major issue of concern to physicians aiming to implement sepsis guidelines in the ICUs.

Coronary Angiography After Out-of-Hospital Cardiac Arrest Without ST-Segment Elevation: One-Year Outcomes of a Randomized Clinical Trial.

Importance: Myocardial infarction is a frequent cause of out-of-hospital cardiac arrest (OHCA). The long-term effect of early coronary angiography on patients with OHCA with possible coronary trigger but no ST-segment elevation remains unclear. Objective: To compare the clinical outcomes of early unselective angiography with the clinical outcomes of a delayed or selective approach for successfully resuscitated patients with OHCA of presumed cardiac origin without ST-segment elevation at 1-year follow-up. Design, Setting, and Participants: The TOMAHAWK trial was a multicenter, international (Germany and Denmark), investigator-initiated, open-label, randomized clinical trial enrolling 554 patients between November 23, 2016, to September 20, 2019. Patients with stable return of spontaneous circulation after OHCA of presumed cardiac origin but without ST-segment elevation on the postresuscitation electrocardiogram were eligible for inclusion. A total of 554 patients were randomized to either immediate coronary angiography after hospital admission or an initial intensive care assessment with delayed or selective angiography after a minimum of 24 hours. All 554 patients were included in survival analyses during the follow-up period of 1 year. Secondary clinical outcomes were assessed only for participants alive at 1 year to account for the competing risk of death. Interventions: Early vs delayed or selective coronary angiography and revascularization if indicated. Main Outcomes and Measures: Evaluations in this secondary analysis included all-cause mortality after 1 year, as well as severe neurologic deficit, myocardial infarction, and rehospitalization for congestive heart failure in survivors at 1 year. Results: A total of 281 patients were randomized to the immediate angiography group and 273 to the delayed or selective group, with a median age of 70 years (IQR, 60-78 years). A total of 369 of 530 patients (69.6%) were male, and 268 of 483 patients (55.5%) had a shockable arrest rhythm. At 1 year, all-cause mortality was 60.8% (161 of 265) in the immediate angiography group and 54.3% (144 of 265) in the delayed or selective angiography group without significant difference between the treatment strategies, trending toward an increase in mortality with immediate angiography (hazard ratio, 1.25; 95% CI, 0.99-1.57; P = .05). For patients surviving until 1 year, the rates of severe neurologic deficit, myocardial infarction, and rehospitalization for congestive heart failure were similar between the groups. Conclusions and Relevance: This study found that a strategy of immediate coronary angiography does not provide clinical benefit compared with a delayed or selective invasive approach for patients 1 year after resuscitated OHCA of presumed coronary cause and without ST-segment elevation. Trial Registration: ClinicalTrials.gov Identifier: NCT02750462.

Effect of Automated Telephone Infectious Disease Consultations to Nonacademic Hospitals on 30-Day Mortality Among Patients With Staphylococcus aureus Bacteremia: The SUPPORT Cluster Randomized Clinical Trial.

Importance: Staphylococcus aureus bacteremia (SAB) is a common and potentially severe infectious disease (ID). Retrospective studies and derived meta-analyses suggest that bedside infectious disease consultation (IDC) for SAB is associated with improved survival; however, such IDCs might not always be possible because of the lack of ID specialists, particularly at nonacademic hospitals. Objectives: To investigate whether unsolicited telephone IDCs (triggered by an automated blood stream infection reporting system) to nonacademic hospitals improved 30-day all-cause mortality in patients with SAB. Design, Setting, and Participants: This patient-blinded, multicenter, interventional, cluster randomized, controlled, crossover clinical trial was conducted in 21 rural, nonacademic hospitals in Thuringia, Germany. From July 1, 2016, to December 31, 2018, 1029 blood culture reports were assessed for eligibility. A total of 386 patients were enrolled, whereas 643 patients were not enrolled for the following reasons: death before enrollment (n = 59); palliative care (n = 41); recurrence of SAB (n = 9); discharge from the hospital before enrollment (n = 77); age younger than 18 years (n = 5); duplicate report from a single patient (n = 26); late report (n = 17); blood culture reported during the washout phase (n = 48); and no signed informed consent for other or unknown reasons (n = 361). Interventions: During the ID intervention phase, ID specialists from Jena University Hospital provided unsolicited telephone IDCs to physicians treating patients with SAB. During the control phase, patients were treated according to local standards. Crossover was performed after including 15 patients or, at the latest, 1 year after the first patient was included. Main Outcomes and Measures: Thirty-day all-cause mortality. Results: A total of 386 patients (median [IQR] age, 75 [63-82] years; 261 [67.6%] male) were included, with 177 randomized to the IDC group and 209 to the control group. The 30-day all-cause mortality rate did not differ between the IDC and control groups (relative risk reduction [RRR], 0.12; 95% CI, -2.17 to 0.76; P = .81). No evidence was found of a difference in secondary outcomes, including 90-day mortality (RRR, 0.17; 95% CI, -0.59 to 0.57; P = .62), 90-day recurrence (RRR, 0.10; 95% CI, -2.51 to 0.89; P = .89), and hospital readmission (RRR, 0.04; 95% CI, -0.63 to 0.48; P = .90). Exploratory evidence suggested that indicators of quality of care were potentially realized more often in the IDC group than in the control group (relative quality improvement, 0.16; 95% CI, 0.08-0.26; P = .01). Conclusions and Relevance: In this cluster randomized clinical trial, unsolicited telephone IDC, although potentially enhancing quality of care, did not improve 30-day all-cause mortality in patients with SAB. Trial Registration: drks.de Identifier: DRKS00010135.