Introduction: Community-acquired pneumonia (CAP) is a significant global health problem and leading cause of death and hospitalization in both the US and abroad. Increasing macrolide resistance among ...Streptococcus pneumoniae and other pathogens results in a greater disease burden, along with changing demographics and a higher preponderance of comorbid conditions.
Areas covered: This review summarizes current data on the clinical and economic burden of CAP, with particular focus on community-acquired bacterial pneumonia (CABP). Incidence, morbidity and mortality, and healthcare costs for the US and other regions of the world are among the topics covered. Major factors that are believed to be contributing to the increased impact of CABP, including antimicrobial resistance, the aging population, and the incidence of comorbidities are discussed, as well as unmet needs in current CABP management.
Expert commentary: The clinical and economic burden of CABP is staggering, far-reaching, and expected to increase in the future as new antibiotic resistance mechanisms emerge and the world's population ages. Important measures must be initiated to stabilize and potentially decrease this burden. Urgent needs in CABP management include the development of new antimicrobials, adjuvant therapies, and rapid diagnostics.
In January 2015, an outbreak of undiagnosed human immunodeficiency virus (HIV) infections among persons who inject drugs (PWID) was recognized in rural Indiana. By September 2016, 205 persons in this ...community of approximately 4400 had received a diagnosis of HIV infection. We report results of new approaches to analyzing epidemiologic and laboratory data to understand transmission during this outbreak. HIV genetic distances were calculated using the polymerase region. Networks were generated using data about reported high-risk contacts, viral genetic similarity, and their most parsimonious combinations. Sample collection dates and recency assay results were used to infer dates of infection. Epidemiologic and laboratory data each generated large and dense networks. Integration of these data revealed subgroups with epidemiologic and genetic commonalities, one of which appeared to contain the earliest infections. Predicted infection dates suggest that transmission began in 2011, underwent explosive growth in mid-2014, and slowed after the declaration of a public health emergency. Results from this phylodynamic analysis suggest that the majority of infections had likely already occurred when the investigation began and that early transmission may have been associated with sexual activity and injection drug use. Early and sustained efforts are needed to detect infections and prevent or interrupt rapid transmission within networks of uninfected PWID.
Objectives
The influence of socioeconomic disparities on adults with pneumonia is not well understood. The objective of our study was to evaluate the relationship between community-level ...socioeconomic position, as measured by an area deprivation index, and the incidence, severity, and outcomes among adults with community-acquired pneumonia (CAP).
Methods
This was an ancillary study of a population-based, prospective cohort study of patients hospitalized with CAP in Louisville, Kentucky, from June 1, 2013, through May 31, 2015. We used a race-specific, block group–level area deprivation index as a proxy for community-level socioeconomic position and evaluated it as a predictor of CAP incidence, CAP severity, early clinical improvement, 30-day mortality, and 1-year mortality.
Results
The cohort comprised 6349 unique adults hospitalized with CAP. CAP incidence per 100 000 population increased significantly with increasing levels of area deprivation, from 303 in tertile 1 (low deprivation), to 467 in tertile 2 (medium deprivation), and 553 in tertile 3 (high deprivation) (P < .001). Adults in medium- and high-deprivation areas had significantly higher odds of severe CAP (tertile 2 odds ratio OR = 1.2 95% confidence interval (CI), 1.06-1.39; tertile 3 OR = 1.4 95% CI, 1.18-1.64 and 1-year mortality (tertile 2 OR = 1.3 95% CI, 1.11-1.54, tertile 3 OR = 1.3 95% CI, 1.10-1.64) than adults in low-deprivation areas.
Conclusions
Compared with adults residing in low-deprivation areas, adults residing in high-deprivation areas had an increased incidence of CAP, and they were more likely to have severe CAP. Beyond 30 days of care, we identified an increased long-term mortality for persons in high-deprivation areas. Community-level socioeconomic position should be considered an important factor for research in CAP and policy decisions.
Summary Inflammation is a double-edged sword in the outcome of pneumonia. On the one hand, an effective and timely inflammatory response is required to eliminate the invading respiratory pathogen. On ...the other, a toxic and prolonged inflammatory response may result in lung injury and poor outcomes, even in those receiving advanced medical care. This review focuses on recent understanding of the dynamics of the cytokine response, neutrophil activity, and responsiveness to cytokines and neutrophil lifespan as major elements of lung inflammation resulting in favorable or poor outcomes in lung infection primarily due to pneumococcus and influenza virus. Although some progress has been made in our understanding of the molecular mechanisms of the pneumonia inflammation axis composed of cytokines modulating neutrophil activation and neutrophil apoptosis, important questions remain to be answered. The degree of neutrophil activation, generation of reactive oxygen species, and the release of granule antimicrobial peptides play a key role in microbial pathogen clearance; however, prolonged neutrophil activation may contribute to lung injury and poor outcomes in pneumonia. Molecular markers of the mechanisms regulating neutrophil survival and apoptosis may help in the identification of novel therapeutic targets to modulate inflammation by inducing timely neutrophil apoptosis. A major task is to identify the mechanisms of dysregulation in inflammation leading to toxic responses, thereby targeting a biomarker and enabling timely therapies to modulate inflammation.
Summary Background The American Thoracic Society and Infectious Diseases Society of America provide guidelines for management of hospital-acquired, ventilator-associated, and health-care-associated ...pneumonias, consisting of empirical antibiotic regimens for patients at risk for multidrug-resistant pathogens. We aimed to improve compliance with these guidelines and assess outcomes. Methods We implemented a performance-improvement initiative in four academic medical centres in the USA with protocol-based education and prospective observation of outcomes. Patients were assessed for severity of illness and followed up until death, hospital discharge, or day 28. We included patients in intensive-care units who were at risk for multidrug-resistant pneumonia and were treated empirically. Findings 303 patients at risk for multidrug-resistant pneumonia were treated empirically, and prescribed treatment was guideline compliant in 129 patients and non-compliant in 174 patients. 44 (34%) patients died before 28 days in the compliance group and 35 (20%) died in the non-compliance group. Five patients in the compliance group and seven in the non-compliance group were lost to follow-up after day 14. Kaplan-Meier estimated survival to 28 days was 65% in the compliance group and 79% in the non-compliance group (p=0·0042). This difference persisted after adjustment for severity of illness. Median length of stay and duration of mechanical ventilation did not differ between groups. Compliance failures included non-use of dual treatment for Gram-negative pathogens in 154 patients and absence of meticillin-resistant Staphylococcus aureus coverage in 24 patients. For patients in whom pathogens were subsequently identified, empirical treatment was active in 79 (81%) of 97 of patients receiving compliant therapy compared with 109 (85%) of 128 of patients receiving non-compliant therapy. Interpretation Because adherence with empirical treatment was associated with increased mortality, we recommend a randomised trial be done before further implementation of these guidelines. Funding Pfizer, US Medical.
Background: Platelets are inflammatory cells with an important role in antimicrobial host defenses. We speculate that an abnormal platelet
count may be a marker of severity in patients with ...community-acquired pneumonia (CAP). The objectives of this study were to
evaluate if abnormal platelet count in hospitalized patients with CAP was associated with 30-day mortality and to compare
platelet count and leukocyte count as predictors of 30-day mortality.
Methods: We performed a retrospective cohort study of 500 consecutive patients hospitalized with CAP at the Veterans Hospital of Louisville,
Kentucky, between June 2001 and March 2006 to investigate the association of platelet count and leukocyte count with 30-day
mortality. Predictor variables were platelet count and leukocyte count. Abnormal platelet count was < 100,000/L (thrombocytopenia)
and > 400,000/L (thrombocytosis). The outcome variable was 30-day mortality. To control for potential confounding, a propensity
score that incorporated 33 variables was used.
Results: Platelet count was strongly associated ( P = .0009) with 30-day mortality, whereas no association was observed for leukocyte count ( P = .5114). High platelet counts resulted in a significantly increased risk of mortality.
Conclusions: Thrombocytopenia and thrombocytosis are associated with mortality in patients hospitalized with CAP. When evaluating an initial
CBC test in patients with CAP, an abnormal platelet count is a better predictor of outcome than an abnormal leukocyte count.
Background. Existing severity assessment tools, such as the pneumonia severity index (PSI) and CURB-65 (tool based on confusion, urea level, respiratory rate, blood pressure, and age <65 years), ...predict 30-day mortality in community-acquired pneumonia (CAP) and have limited ability to predict which patients will require intensive respiratory or vasopressor support (IRVS). Methods. The Australian CAP Study (ACAPS) was a prospective study of 882 episodes in which each patient had a detailed assessment of severity features, etiology, and treatment outcomes. Multivariate logistic regression was performed to identify features at initial assessment that were associated with receipt of IRVS. These results were converted into a simple points-based severity tool that was validated in 5 external databases, totaling 7464 patients. Results. In ACAPS, 10.3% of patients received IRVS, and the 30-day mortality rate was 5.7%. The features statistically significantly associated with receipt of IRVS were low systolic blood pressure (2 points), multilobar chest radiography involvement (1 point), low albumin level (1 point), high respiratory rate (1 point), tachycardia (1 point), confusion (1 point), poor oxygenation (2 points), and low arterial pH (2 points): SMART-COP. A SMART-COP score of <3 points identified 92% of patients who received IRVS, including 84% of patients who did not need immediate admission to the intensive care unit. Accuracy was also high in the 5 validation databases. Sensitivities of PSI and CURB-65 for identifying the need for IRVS were 74% and 39%, respectively. Conclusions. SMART-COP is a simple, practical clinical tool for accurately predicting the need for IRVS that is likely to assist clinicians in determining CAP severity.
Pneumonia is a complex pulmonary disease in need of new clinical approaches. Although triggered by a pathogen, pneumonia often results from dysregulations of host defense that likely precede ...infection. The coordinated activities of immune resistance and tissue resilience then dictate whether and how pneumonia progresses or resolves. Inadequate or inappropriate host responses lead to more severe outcomes such as acute respiratory distress syndrome and to organ dysfunction beyond the lungs and over extended time frames after pathogen clearance, some of which increase the risk for subsequent pneumonia. Improved understanding of such host responses will guide the development of novel approaches for preventing and curing pneumonia and for mitigating the subsequent pulmonary and extrapulmonary complications of pneumonia. The NHLBI assembled a working group of extramural investigators to prioritize avenues of host-directed pneumonia research that should yield novel approaches for interrupting the cycle of unhealthy decline caused by pneumonia. This report summarizes the working group's specific recommendations in the areas of pneumonia susceptibility, host response, and consequences. Overarching goals include the development of more host-focused clinical approaches for preventing and treating pneumonia, the generation of predictive tools (for pneumonia occurrence, severity, and outcome), and the elucidation of mechanisms mediating immune resistance and tissue resilience in the lung. Specific areas of research are highlighted as especially promising for making advances against pneumonia.
BACKGROUND:Chronic immune activation and CD4 T cell depletion are significant pathogenic features of HIV infection. Expression of Fas ligand (FasL), a key mediator of activation-induced cell death in ...T cells, is elevated in people living with HIV-1 infection (PLWH). However, the epigenetic mechanisms underlying the enhanced induction of FasL expression in CD4 T lymphocytes in PLWH are not completely elucidated. Hence, the current work examined the effect of HIV infection on FasL promoter-associated histone modifications and transcriptional regulation in CD4 T lymphocytes in PLWH.
METHOD:Flow cytometric analysis was performed to examine the Fas-FasL expression on total CD4 T cells and naïve/memory CD4 T cell subsets. Epigenetic FasL promoter histone modifications were investigated by chromatin immunoprecipitation-quantitative real-time polymerase chain reaction analysis using freshly isolated total CD4 T lymphocytes from HIV-1 infected and noninfected individuals.
RESULTS:All naïve/memory CD4 T cell subsets from PLWH showed markedly greater frequency of FasL expression. Notably, examination of functional outcome of FasL/Fas co-expression demonstrated the preferential susceptibility of Tcm and Tem subsets to activation-induced apoptosis. Importantly, these CD4 T cells collectively demonstrated a distinct FasL promoter histone profile involving a coordinated cross-talk between histone H3 modifications leading to enhanced FasL gene expression. Specifically, levels of transcriptionally permissive histone H3K4-trimethylation (H3K4Me3) and histone H3K9-acetylation (H3K9Ac) were increased, with a concomitant decrease in the repressive H3K9-trimethylation (H3K9Me3).
CONCLUSION:The present work demonstrates that epigenetic mechanisms involving promoter-histone modifications regulate transcriptional competence and FasL expression in CD4 T cells from PLWH and render them susceptible to activation-induced cell death.
Abstract Background The 2005 guidelines from the American Thoracic Society and the Infectious Diseases Society of America recommend vancomycin trough levels of 15 to 20 mg/L for the therapy of ...hospital-acquired (HAP), ventilator-associated (VAP), and health care–associated (HCAP) pneumonia. Objective The goal of this article was to report the incidence of nephrotoxicity and associated risk factors in intensive care unit patients who received vancomycin for the treatment of HAP, VAP, and HCAP. Methods This was a retrospective analysis of data from a multicenter, observational study of pneumonia patients. Antibiotic-associated nephrotoxicity was defined as either an increase in serum creatinine ≥0.5 mg/dL or 50% above baseline, from initiation of vancomycin to 72 hours after completion of therapy. Univariate and multivariate logistic regression analyses were performed to identify risk factors for development of renal dysfunction. Results Of the 449 patients in the database, 240 received at least one dose of vancomycin and 188 had sufficient data for analysis. In these 188 patients, 63% were male. Mean (SD) age was 58.5 (17.2) years, and the mean Acute Physiology and Chronic Health Evaluation II score was 19.4 (6.4). Nephrotoxicity occurred in 29 of 188 (15.4%) vancomycin-treated patients. In multivariate analysis, initial vancomycin trough levels ≥15 mg/L (odds ratio OR, 5.2 95% CI, 1.9–13.9; P = 0.001), concomitant aminoglycoside use (OR, 2.67 95% CI, 1.09–6.54; P = 0.03), and duration of vancomycin therapy (OR for each additional treatment day, 1.12 95% CI, 1.02–1.23; P = 0.02) were independently associated with nephrotoxicity. The incidence of nephrotoxicity increased as a function of the initial vancomycin trough level, rising from 7% at a trough <10 mg/L to 34% at >20 mg/L ( P = 0.001). The mean time to nephrotoxicity decreased from 8.8 days at vancomycin trough levels <15 mg/L to 7.4 days at >20 mg/L (Kaplan-Meier analysis, P = 0.0003). Conclusions Nephrotoxicity may be common among intensive care unit patients with pneumonia treated with broad-spectrum antibiotic therapy that includes vancomycin. The finding that an initial vancomycin trough level ≥15 mg/L may be an independent risk factor for nephrotoxicity highlights the need for additional studies to assess current recommendations for vancomycin dosing for ICU patients with pneumonia.
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