Infectious Diseases Consultation Associated With Reduced Mortality in Gram-Negative Bacteremia.

Gram-negative bacteremia (GN-BSI) can cause significant morbidity and mortality, but the benefit of infectious diseases consultation (IDC) is not well defined. A 24-site observational cohort study of unique hospitalized patients with 4861 GN-BSI episodes demonstrated a 40% decreased risk of 30-day mortality in patients with IDC compared to those without IDC.

Developing a diagnosis calculator to estimate the probability of bacterial pneumonia.

Misdiagnosis of bacterial pneumonia increases risk of exposure to inappropriate antibiotics and adverse events. We developed a diagnosis calculator (https://calculator.testingwisely.com) to inform clinical diagnosis of community-acquired bacterial pneumonia using objective indicators, including incidence of disease, risk factors, and sensitivity and specificity of diagnostic tests, that were identified through literature review.

Predictors of in-hospital mortality in a cohort of people living with HIV (PLHIV) admitted to an academic medical intensive care unit from 2009 to 2014: A retrospective cohort study.

Outcomes for critically ill people living with human immunodeficiency virus (PLHIV) have changed with the use of antiretroviral therapy (ART). To identify these outcomes and correlates of mortality in a contemporary critically ill cohort in an urban academic medical center in Baltimore, a city with a high burden of HIV, we conducted a retrospective cohort study of individuals admitted to a medical intensive care unit (MICU) at a tertiary care center between 2009 and 2014. PLHIV who were at least 18 years of age with an index MICU admission of ≥24 hours during the 5-year study period were included in this analysis. Data were obtained for participants from the time of MICU admission until hospital discharge and up to 180 days after MICU admission. Logistic regression was used to identify independent predictors of hospital mortality. Between June 2009 and June 2014, 318 PLHIV admitted to the MICU met inclusion criteria. Eighty-six percent of the patients were non-Hispanic Blacks. Poorly controlled HIV was very common with 70.2% of patients having a CD4 cell count <200 cells/mm3 within 3 months prior to admission and only 34% of patients having an undetectable HIV viral load. Hospital mortality for the cohort was 17%. In a univariate model, mortality did not differ by demographic variables, CD4 cell count, HIV viral load, or ART use. Regression analysis adjusted by relevant covariates revealed that MICU patients admitted from the hospital ward were 6.4 times more likely to die in hospital than those admitted from emergency department. Other positive predictors were a diagnosis of end-stage liver disease, cardiac arrest, ventilator-dependent respiratory failure, vasopressor requirement, non-Hodgkin lymphoma, and symptomatic cytomegalovirus disease. In conclusion, in this critically ill cohort with HIV infection, most predictors of mortality were not directly related to HIV and were similar to those for the general population.

A cytosolic juxtamembrane interface modulates plexin A3 oligomerization and signal transduction.

Plexins (plxns) are transmembrane (TM) receptors involved in the guidance of vascular, lymphatic vessel, and neuron growth as well as cancer metastasis. Plxn signaling results in cytosolic GTPase-activating protein activity, and previous research implicates dimerization as important for activation of plxn signaling. Purified, soluble plxn extracellular and cytosolic domains exhibit only weak homomeric interactions, suggesting a role for the plxn TM and juxtamembrane regions in homooligomerization. In this study, we consider a heptad repeat in the Danio rerio PlxnA3 cytosolic juxtamembrane domain (JM) for its ability to influence PlxnA3 homooligomerization in TM-domain containing constructs. Site-directed mutagenesis in conjunction with the AraTM assay and bioluminescent energy transfer (BRET²) suggest an interface involving a JM heptad repeat, in particular residue M1281, regulates PlxnA3 homomeric interactions when examined in constructs containing an ectodomain, TM and JM domain. In the presence of a neuropilin-2a co-receptor and semaphorin 3F ligand, disruption to PlxnA3 homodimerization caused by an M1281F mutation is eliminated, suggesting destabilization of the PlxnA3 homodimer in the JM is not sufficient to disrupt co-receptor complex formation. In contrast, enhanced homodimerization of PlxnA3 caused by mutation M1281L remains even in the presence of ligand semaphorin 3F and co-receptor neuropilin-2a. Consistent with this pattern of PlxnA3 dimerization in the presence of ligand and co-receptor, destabilizing mutations to PlxnA3 homodimerization (M1281F) are able to rescue motor patterning defects in sidetracked zebrafish embryos, whereas mutations that enhance PlxnA3 homodimerization (M1281L) are not. Collectively, our results indicate the JM heptad repeat, in particular residue M1281, forms a switchable interface that modulates both PlxnA3 homomeric interactions and signal transduction.