Severe Pneumococcal Pneumonia Causes Acute Cardiac Toxicity and Subsequent Cardiac Remodeling

Chronic TNF exposure induces glucocorticoid-like immunosuppression in the alveolar macrophages of aged mice that enhances their susceptibility to pneumonia

Chronic low-grade inflammation, particularly elevated tumor necrosis factor (TNF) levels, occurs due to advanced age and is associated with greater susceptibility to infection. One reason for this is age-dependent macrophage dysfunction (ADMD). Herein, we use the adoptive transfer of alveolar macrophages (AM) from aged mice into the airway of young mice to show that inherent age-related defects in AM were sufficient to increase the susceptibility to Streptococcus pneumoniae, a Gram-positive bacterium and the leading cause of community-acquired pneumonia. MAPK phosphorylation arrays using AM lysates from young and aged wild-type (WT) and TNF knockout (KO) mice revealed multilevel TNF-mediated suppression of kinase activity in aged mice. RNAseq analyses of AM validated the suppression of MAPK signaling as a consequence of TNF during aging. Two regulatory phosphatases that suppress MAPK signaling, Dusp1 and Ptprs, were confirmed to be upregulated with age and as a result of TNF exposure both ex vivo and in vitro. Dusp1 is known to be responsible for glucocorticoid-mediated immune suppression, and dexamethasone treatment increased Dusp1 and Ptprs expression in cells and recapitulated the ADMD phenotype. In young mice, treatment with dexamethasone increased the levels of Dusp1 and Ptprs and their susceptibility to infection. TNF-neutralizing antibody reduced Dusp1 and Ptprs levels in AM from aged mice and reduced pneumonia severity following bacterial challenge. We conclude that chronic exposure to TNF increases the expression of the glucocorticoid-associated MAPK signaling suppressors, Dusp1 and Ptprs, which inhibits AM activation and increases susceptibility to bacterial pneumonia in older adults.

Diabetes Mellitus and Pneumococcal Pneumonia

Currently, there are more than 500 million people suffering from diabetes around the world. People aged 65 years or older are the most affected by this disease, and it is estimated that approximately 96% of diabetes cases worldwide are type 2 diabetes. People with diabetes mellitus are at an increased risk of infections such as pneumonia, due to a series of factors that may contribute to immune dysfunction, including hyperglycemia, inhibition of neutrophil chemotaxis, impaired cytokine production, phagocytic cell dysfunction, altered T cell-mediated immune responses and the co-existence of chronic comorbidities. Rates of infection, hospitalization and mortality in diabetic patients are reported to be higher than in the general population. Research into the risk of infectious diseases such as pneumonia in these patients is very important because it will help improve their management and treatment.

Streptococcus pneumoniae as a colonizing agent of the Nasopharynx - Oropharynx in adults: A systematic review and meta-analysis

BACKGROUND

Streptococcus pneumoniae (Spn) is a commensal pathogen that usually colonizes the upper respiratory tract of children. Likewise, Spn colonization has been considered a critical factor in the development of pneumococcal invasive disease. However, Spn prevalence in adults remains unclear. This study performs a systematic review and meta-analysis to explore the prevalence of Spn Nasopharynx - Oropharynx Colonization (NOC) in adults.

METHODS

A Systematic review of scientific databases was utilized to identify eligible studies that follow strict selection criteria. Subsequently, a meta-analysis was conducted to establish NOC prevalence in adults (≥18 years old). The heterogeneity and sensitivity analyses were assessed using the microorganism identification technique, sample type, and age subgroups.

RESULTS

Initial selection includes 69 studies, with 37 selected for the meta-analysis, involving 23,724 individuals. The overall prevalence (95 % CI) of Spn NOC among adults was 6 % (5-9). The subgroup analysis revealed that young adults (YA), 18-64 years old, had a prevalence of 10 %, whereas older adults (OA), ≥65 years old, had a prevalence of 2 %. The identification of Spn NOC may vary depending on the method of diagnosis used. High heterogeneity (I2 > 90 %) was observed but diminished to 70 % when the analysis was restricted to oropharyngeal swabs as an identification method. Furthermore, heterogeneity decreased to 58 % when exclusively employing traditional culture as the identification method.

CONCLUSIONS

This study found a low prevalence of Spn NOC in adults. Notably, the prevalence of Spn NOC was higher in younger adults than in older adults. It is essential to highlight a significant heterogeneity among studies, which indicates there is no standardized method of Spn NOC identification.

Long-Term Outcomes in Severe Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is globally one of the major causes of hospitalization and mortality. Severe CAP (sCAP) presents great challenges and need a comprehensive understanding of its long-term outcomes. Cardiovascular events and neurological impairment, due to persistent inflammation and hypoxemia, contribute to long-term outcomes in CAP, including mortality. Very few data are available in the specific population of sCAP. Multiple studies have reported variable 1-year mortality rates for patients with CAP up to 40.7%, with a clear influence by age, comorbidities, and disease severity. In terms of treatment, the potential protective role of macrolides in reducing mortality emphasizes the importance of appropriate empiric antibiotic therapy. This narrative review explores the growing interest in the literature focusing on the long-term implications of sCAP. Improved understanding of long-term outcomes in sCAP can facilitate targeted interventions and enhance posthospitalization care protocols.

Cell type-specific molecular mechanisms and implications of necroptosis in inflammatory respiratory diseases

Necroptosis is generally considered as an inflammatory cell death form. The core regulators of necroptotic signaling are receptor-interacting serine-threonine protein kinases 1 (RIPK1) and RIPK3, and the executioner, mixed lineage kinase domain-like pseudokinase (MLKL). Evidence demonstrates that necroptosis contributes profoundly to inflammatory respiratory diseases that are common public health problem. Necroptosis occurs in nearly all pulmonary cell types in the settings of inflammatory respiratory diseases. The influence of necroptosis on cells varies depending upon the type of cells, tissues, organs, etc., which is an important factor to consider. Thus, in this review, we briefly summarize the current state of knowledge regarding the biology of necroptosis, and focus on the key molecular mechanisms that define the necroptosis status of specific cell types in inflammatory respiratory diseases. We also discuss the clinical potential of small molecular inhibitors of necroptosis in treating inflammatory respiratory diseases, and describe the pathological processes that engage cross talk between necroptosis and other cell death pathways in the context of respiratory inflammation. The rapid advancement of single-cell technologies will help understand the key mechanisms underlying cell type-specific necroptosis that are critical to effectively treat pathogenic lung infections and inflammatory respiratory diseases.

A Multicentric Observational Study to Determine Myocardial Injury in Severe Community-Acquired Pneumonia (sCAP)

Background: Severe community-acquired pneumonia (sCAP) is the most frequent admission for acute respiratory failure in intensive care medicine. Observational studies have found a correlation between patients who were admitted with CAP and the development of cardiovascular events. The risk of acute myocardial damage in patients with CAP is particularly high within the first 30 days of hospitalization. Research design and methods: Multicenter prospective cohort analysis conducted in consecutive patients admitted to an ICU with microbiologically confirmed diagnoses of sCAP. The aim was to determine any structural cardiac damage detected by advanced imagining techniques (cardiac MRI) and cardiac biomarkers in patients with sCAP. The patients were stratified, according to their etiology, into pneumococcal or not-pneumococcal sCAP. The primary outcome was cardiac damage at day 5 and 7 of clinical presentation. Results: A total of 23 patients were consecutively and prospectively enrolled for two winter periods. No significant differences were observed between the median troponin when comparing the pneumococcal vs. non-pneumococcal. The incidence of myocardial damage was numerically higher in the pneumococcal subgroup (70% vs. 50%, p = 0.61) on day 5 and on day 7 (53% vs. 40%, p = 0.81) but did not achieve significance. Confirming a correlation between the biomarkers of cell damage and the biomarkers of myocardial damage, only a positive and significant correlation was observed between h-FABP and DNA on day 1 (r = 0.74; p < 0.01) and day 3 (r = 0.83; p < 0.010). Twenty cardiac MRIs were performed on the 23 patients (87%). No presence of fibrosis was observed in any of the studies carried out within the first 15 days of admission. Conclusions: No significant myocardial damage was found in patients with sCAP independent of the bacterial etiology in accordance with biomarker alterations (Troponin and/or h-FABP) or cardiac MRI. Using cardiac MRI, we could not find any presence of myocardial fibrosis within the first 15 days of admission.

Is the long-term mortality similar in COVID-19 and community-acquired pneumonia?

Introduction

There are no data on the association of type of pneumonia and long-term mortality by the type of pneumonia (COVID-19 or community-acquired pneumonia [CAP]) on long-term mortality after an adjustment for potential confounding variables. We aimed to assess the type of pneumonia and risk factors for long-term mortality in patients who were hospitalized in conventional ward and later discharged.

Methods

Retrospective analysis of two prospective and multicentre cohorts of hospitalized patients with COVID-19 and CAP. The main outcome under study was 1-year mortality in hospitalized patients in conventional ward and later discharged. We adjusted a Bayesian logistic regression model to assess associations between the type of pneumonia and 1-year mortality controlling for confounders.

Results

The study included a total of 1,693 and 2,374 discharged patients in the COVID-19 and CAP cohorts, respectively. Of these, 1,525 (90.1%) and 2,249 (95%) patients underwent analysis. Until 1-year follow-up, 69 (4.5%) and 148 (6.6%) patients from the COVID-19 and CAP cohorts, respectively, died (p = 0.008). However, the Bayesian model showed a low probability of effect (PE) of finding relevant differences in long-term mortality between CAP and COVID-19 (odds ratio 1.127, 95% credibility interval 0.862-1.591; PE = 0.774).

Conclusion

COVID-19 and CAP have similar long-term mortality after adjusting for potential confounders.

The pathophysiological role of receptor-interacting protein kinase 3 in cardiovascular disease

Recent studies have found that receptor interacting protein kinase 3 (RIPK3) can mediate CaMK Ⅱ phosphorylation and oxidation, open mitochondrial permeability transition pore (mPTP), and induce myocardial necroptosis. The increased expression or phosphorylation of RIPK3 is one of the important markers of necroptosis; Inhibition of CaMK Ⅱ phosphorylation or oxidation significantly reduces RIPK3 mediated myocardial necroptosis; Studies have shown that necroptosis plays an important role in the occurrence and development of cardiovascular diseases; Using the selective inhibitor GSK '872 of RIPK3 can effectively inhibit the occurrence and development of cardiovascular diseases, and can reverse cardiovascular and cardiac dysfunction caused by overexpression of RIPK3. In this review, we provide a brief overview of the current knowledge on RIPK3 in mediating necroptosis, inflammatory response, and oxidative stress, and discussed the role of RIPK3 in cardiovascular diseases such as atherosclerosis, myocardial ischaemia, myocardial infarction, and heart failure.

Regulated cell death pathways in cardiomyopathy

Heart disease is a worldwide health menace. Both intractable primary and secondary cardiomyopathies contribute to malignant cardiac dysfunction and mortality. One of the key cellular processes associated with cardiomyopathy is cardiomyocyte death. Cardiomyocytes are terminally differentiated cells with very limited regenerative capacity. Various insults can lead to irreversible damage of cardiomyocytes, contributing to progression of cardiac dysfunction. Accumulating evidence indicates that majority of cardiomyocyte death is executed by regulating molecular pathways, including apoptosis, ferroptosis, autophagy, pyroptosis, and necroptosis. Importantly, these forms of regulated cell death (RCD) are cardinal features in the pathogenesis of various cardiomyopathies, including dilated cardiomyopathy, diabetic cardiomyopathy, sepsis-induced cardiomyopathy, and drug-induced cardiomyopathy. The relevance between abnormity of RCD with adverse outcome of cardiomyopathy has been unequivocally evident. Therefore, there is an urgent need to uncover the molecular and cellular mechanisms for RCD in order to better understand the pathogenesis of cardiomyopathies. In this review, we summarize the latest progress from studies on RCD pathways in cardiomyocytes in context of the pathogenesis of cardiomyopathies, with particular emphasis on apoptosis, necroptosis, ferroptosis, autophagy, and pyroptosis. We also elaborate the crosstalk among various forms of RCD in pathologically stressed myocardium and the prospects of therapeutic applications targeted to various cell death pathways.

The Global Burden of Community-Acquired Pneumonia in Adults, Encompassing Invasive Pneumococcal Disease and the Prevalence of Its Associated Cardiovascular Events, with a Focus on Pneumolysin and Macrolide Antibiotics in Pathogenesis and Therapy

Despite innovative advances in anti-infective therapies and vaccine development technologies, community-acquired pneumonia (CAP) remains the most persistent cause of infection-related mortality globally. Confronting the ongoing threat posed by Streptococcus pneumoniae (the pneumococcus), the most common bacterial cause of CAP, particularly to the non-immune elderly, remains challenging due to the propensity of the elderly to develop invasive pneumococcal disease (IPD), together with the predilection of the pathogen for the heart. The resultant development of often fatal cardiovascular events (CVEs), particularly during the first seven days of acute infection, is now recognized as a relatively common complication of IPD. The current review represents an update on the prevalence and types of CVEs associated with acute bacterial CAP, particularly IPD. In addition, it is focused on recent insights into the involvement of the pneumococcal pore-forming toxin, pneumolysin (Ply), in subverting host immune defenses, particularly the protective functions of the alveolar macrophage during early-stage disease. This, in turn, enables extra-pulmonary dissemination of the pathogen, leading to cardiac invasion, cardiotoxicity and myocardial dysfunction. The review concludes with an overview of the current status of macrolide antibiotics in the treatment of bacterial CAP in general, as well as severe pneumococcal CAP, including a consideration of the mechanisms by which these agents inhibit the production of Ply by macrolide-resistant strains of the pathogen.

Impact of macrolide treatment on long-term mortality in patients admitted to the ICU due to CAP: a targeted maximum likelihood estimation and survival analysis

INTRODUCTION

Patients with community-acquired pneumonia (CAP) admitted to the intensive care unit (ICU) have high mortality rates during the acute infection and up to ten years thereafter. Recommendations from international CAP guidelines include macrolide-based treatment. However, there is no data on the long-term outcomes of this recommendation. Therefore, we aimed to determine the impact of macrolide-based therapy on long-term mortality in this population.

METHODS

Registered patients in the MIMIC-IV database 16 years or older and admitted to the ICU due to CAP were included. Multivariate analysis, targeted maximum likelihood estimation (TMLE) to simulate a randomised controlled trial, and survival analyses were conducted to test the effect of macrolide-based treatment on mortality six-month (6 m) and twelve-month (12 m) after hospital admission. A sensitivity analysis was performed excluding patients with Pseudomonas aeruginosa or MRSA pneumonia to control for Healthcare-Associated Pneumonia (HCAP).

RESULTS

3775 patients were included, and 1154 were treated with a macrolide-based treatment. The non-macrolide-based group had worse long-term clinical outcomes, represented by 6 m [31.5 (363/1154) vs 39.5 (1035/2621), p < 0.001] and 12 m mortality [39.0 (450/1154) vs 45.7 (1198/2621), p < 0.001]. The main risk factors associated with long-term mortality were Charlson comorbidity index, SAPS II, septic shock, and respiratory failure. Macrolide-based treatment reduced the risk of dying at 6 m [HR (95% CI) 0.69 (0.60, 0.78), p < 0.001] and 12 m [0.72 (0.64, 0.81), p < 0.001]. After TMLE, the protective effect continued with an additive effect estimate of - 0.069.

CONCLUSION

Macrolide-based treatment reduced the hazard risk of long-term mortality by almost one-third. This effect remains after simulating an RCT with TMLE and the sensitivity analysis for the HCAP classification.

Major adverse cardiovascular events are associated with necroptosis during severe COVID-19

BACKGROUND

The mechanisms used by SARS-CoV-2 to induce major adverse cardiac events (MACE) are unknown. Thus, we aimed to determine if SARS-CoV-2 can induce necrotic cell death to promote MACE in patients with severe COVID-19.

METHODS

This observational prospective cohort study includes experiments with hamsters and human samples from patients with severe COVID-19. Cytokines and serum biomarkers were analysed in human serum. Cardiac transcriptome analyses were performed in hamsters' hearts.

RESULTS

From a cohort of 70 patients, MACE was documented in 26% (18/70). Those who developed MACE had higher Log copies/mL of SARS-CoV-2, troponin-I, and pro-BNP in serum. Also, the elevation of IP-10 and a major decrease in levels of IL-17ɑ, IL-6, and IL-1rɑ were observed. No differences were found in the ability of serum antibodies to neutralise viral spike proteins in pseudoviruses from variants of concern. In hamster models, we found a stark increase in viral titters in the hearts 4 days post-infection. The cardiac transcriptome evaluation resulted in the differential expression of ~ 9% of the total transcripts. Analysis of transcriptional changes in the effectors of necroptosis (mixed lineage kinase domain-like, MLKL) and pyroptosis (gasdermin D) showed necroptosis, but not pyroptosis, to be elevated. An active form of MLKL (phosphorylated MLKL, pMLKL) was elevated in hamster hearts and, most importantly, in the serum of MACE patients.

CONCLUSION

SARS-CoV-2 identification in the systemic circulation is associated with MACE and necroptosis activity. The increased pMLKL and Troponin-I indicated the occurrence of necroptosis in the heart and suggested necroptosis effectors could serve as biomarkers and/or therapeutic targets. Trial registration Not applicable.

Transient increase in atherosclerotic plaque macrophage content following Streptococcus pneumoniae pneumonia in ApoE-deficient mice

Introduction

Despite epidemiological associations between community acquired pneumonia (CAP) and myocardial infarction, mechanisms that modify cardiovascular disease during CAP are not well defined. In particular, largely due to a lack of relevant experimental models, the effect of pneumonia on atherosclerotic plaques is unclear. We describe the development of a murine model of the commonest cause of CAP, Streptococcus pneumoniae pneumonia, on a background of established atherosclerosis. We go on to use our model to investigate the effects of pneumococcal pneumonia on atherosclerosis.

Methods

C57BL/6J and ApoE-/- mice were fed a high fat diet to promote atherosclerotic plaque formation. Mice were then infected with a range of S. pneumoniae serotypes (1, 4 or 14) with the aim of establishing a model to study atherosclerotic plaque evolution after pneumonia and bacteremia. Laser capture microdissection of plaque macrophages enabled transcriptomic analysis.

Results

Intratracheal instillation of S. pneumoniae in mice fed a cholate containing diet resulted in low survival rates following infection, suggestive of increased susceptibility to severe infection. Optimization steps resulted in a final model of male ApoE-/- mice fed a Western diet then infected by intranasal instillation of serotype 4 (TIGR4) S. pneumoniae followed by antibiotic administration. This protocol resulted in high rates of bacteremia (88.9%) and survival (88.5%). Pneumonia resulted in increased aortic sinus plaque macrophage content 2 weeks post pneumonia but not at 8 weeks, and no difference in plaque burden or other plaque vulnerability markers were found at either time point. Microarray and qPCR analysis of plaque macrophages identified downregulation of two E3 ubiquitin ligases, Huwe1 and Itch, following pneumonia. Treatment with atorvastatin failed to alter plaque macrophage content or other plaque features.

Discussion

Without antibiotics, ApoE-/- mice fed a high fat diet were highly susceptible to mortality following S. pneumoniae infection. The major infection associated change in plaque morphology was an early increase in plaque macrophages. Our results also hint at a role for the ubiquitin proteasome system in the response to pneumococcal infection in the plaque microenvironment.

Pneumonia-Induced Inflammation, Resolution and Cardiovascular Disease: Causes, Consequences and Clinical Opportunities

Pneumonia is inflammation in the lungs, which is usually caused by an infection. The symptoms of pneumonia can vary from mild to life-threatening, where severe illness is often observed in vulnerable populations like children, older adults, and those with preexisting health conditions. Vaccines have greatly reduced the burden of some of the most common causes of pneumonia, and the use of antimicrobials has greatly improved the survival to this infection. However, pneumonia survivors do not return to their preinfection health trajectories but instead experience an accelerated health decline with an increased risk of cardiovascular disease. The mechanisms of this association are not well understood, but a persistent dysregulated inflammatory response post-pneumonia appears to play a central role. It is proposed that the inflammatory response during pneumonia is left unregulated and exacerbates atherosclerotic vascular disease, which ultimately leads to adverse cardiac events such as myocardial infarction. For this reason, there is a need to better understand the inflammatory cross talk between the lungs and the heart during and after pneumonia to develop therapeutics that focus on preventing pneumonia-associated cardiovascular events. This review will provide an overview of the known mechanisms of inflammation triggered during pneumonia and their relevance to the increased cardiovascular risk that follows this infection. We will also discuss opportunities for new clinical approaches leveraging strategies to promote inflammatory resolution pathways as a novel therapeutic target to reduce the risk of cardiac events post-pneumonia.

Acute organ injury and long-term sequelae of severe pneumococcal infections

Streptococcus pneumoniae (Spn) is a major public health problem, as it is a main cause of otitis media, community-acquired pneumonia, bacteremia, sepsis, and meningitis. Acute episodes of pneumococcal disease have been demonstrated to cause organ damage with lingering negative consequences. Cytotoxic products released by the bacterium, biomechanical and physiological stress resulting from infection, and the corresponding inflammatory response together contribute to organ damage accrued during infection. The collective result of this damage can be acutely life-threatening, but among survivors, it also contributes to the long-lasting sequelae of pneumococcal disease. These include the development of new morbidities or exacerbation of pre-existing conditions such as COPD, heart disease, and neurological impairments. Currently, pneumonia is ranked as the 9^th leading cause of death, but this estimate only considers short-term mortality and likely underestimates the true long-term impact of disease. Herein, we review the data that indicates damage incurred during acute pneumococcal infection can result in long-term sequelae which reduces quality of life and life expectancy among pneumococcal disease survivors.

[Community-acquired pneumonia]

RISK FACTORS FOR SEVERE COURSES

The CRB-65 score is recommended as a risk predictor, as well as consideration of unstable comorbidities and oxygenation.

GROUPING OF COMMUNITY-ACQUIRED PNEUMONIA

Community-acquired pneumonia is divided into 3 groups: mild pneumonia, moderate pneumonia, severe pneumonia. Whether there is a curative vs palliative treatment goal should be determined early.

DIAGNOSTIC RECOMMENDATION

An X-ray chest radiograph is recommended to confirm the diagnosis, also in the outpatient setting if possible. Sonography of the thorax is an alternative, asking for additional imaging if negative. Streptococcus pneumoniae remains the most common bacterial pathogen.

THERAPY

Community-acquired pneumonia continues to be associated with high morbidity and lethality. Prompt diagnosis and prompt initiation of risk-adapted antimicrobial therapy are essential measures. However, in times of COVID-19, as well as the current influenza and RSV epidemic, purely viral pneumonias must also be expected. At least with COVID-19, antibiotics can often be avoided. Antiviral and anti-inflammatory drugs are used here.

POST-ACUTE COURSE

Patients after community-acquired pneumonia have increased acute and long-term mortality due to cardiovascular events in particular. The focus of research is on improved pathogen identification, a better understanding of the host response with the potential of developing specific therapeutics, the role of comorbidities, and the long-term consequences of the acute illness.

Necroptosis Drives Major Adverse Cardiovascular Events During Severe COVID-19

Background The mechanisms used by SARS-CoV-2 to induce major adverse cardiac events (MACE) are unknown. Thus, we aimed to determine if SARS-CoV-2 can infect the heart to kill cardiomyocytes and induce MACE in patients with severe COVID-19. Methods This observational prospective cohort study includes experiments with hamsters and human samples from patients with severe COVID-19. Cytokines and serum biomarkers were analyzed in human serum. Cardiac transcriptome analyses were performed in hamsters' hearts. Results From a cohort of 70 patients, MACE was documented in 26% (18/70). Those who developed MACE had higher Log copies/mL of SARS-CoV-2, troponin-I, and pro-BNP in serum. Also, the elevation of IP-10 and a major decrease in levels of IL-17ɑ, IL-6, and IL-1rɑ were observed. No differences were found in the ability of serum antibodies to neutralize viral spike proteins in pseudoviruses from variants of concern. In hamster models, we found a stark increase in viral titers in the hearts 4 days post-infection. The cardiac transcriptome evaluation resulted in the differential expression of ~ 9% of the total transcripts. Analysis of transcriptional changes of the effectors of necroptosis (mixed lineage kinase domain-like, MLKL) and pyroptosis (gasdermin D) showed necroptosis, but not pyroptosis, to be elevated. Active form of MLKL (phosphorylated MLKL, pMLKL) was elevated in hamster hearts and, most importantly, in the serum of MACE patients. Conclusion SARS-CoV-2 can reach the heart during severe COVID-19 and induce necroptosis in the heart of patients with MACE. Thus, pMLKL could be used as a biomarker of cardiac damage and a therapeutic target. Trial registration: Not applicable.

Cardiovascular Complications in Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is accountable for high mortality in both pediatric and adult populations worldwide, about one-third of hospitalized patients pass away within a year of being discharged from the facility. The high mortality and morbidity rates are closely related to cardiovascular complications that are consequent or concomitant to the acute episode of pneumonia. An updated perspective on the major pathophysiological mechanisms, prevalence, risk factors, outcomes, and relevant treatments of cardiovascular events in CAP patients is provided in the current study. It is possible to evaluate the pathophysiology of cardiac disease in this population based on plaque-related events, such as acute myocardial infarction, or events unrelated to plaque, such as arrhythmias and heart failure. With an absolute rate of cardiovascular problems ranging broadly from 10% to 30%, CAP raises the risk of both plaque-related and plaque-unrelated events. Both in- and out-patients may experience these issues at admission, throughout hospitalization, or even up to a year following discharge. At long-term follow-up, cardiac events account for more than 30% of deaths in CAP patients, making them a significant cause of mortality. If patients at risk for cardiac events are stratified, diagnostic tools, monitoring, and preventive measures may be applied to these patients. A prospective evaluation of cardioprotective treatments is urgently required from a research point of view.

Unmet needs in pneumonia research: a comprehensive approach by the CAPNETZ study group

Introduction

Despite improvements in medical science and public health, mortality of community-acquired pneumonia (CAP) has barely changed throughout the last 15 years. The current SARS-CoV-2 pandemic has once again highlighted the central importance of acute respiratory infections to human health. The “network of excellence on Community Acquired Pneumonia” (CAPNETZ) hosts the most comprehensive CAP database worldwide including more than 12,000 patients. CAPNETZ connects physicians, microbiologists, virologists, epidemiologists, and computer scientists throughout Europe. Our aim was to summarize the current situation in CAP research and identify the most pressing unmet needs in CAP research.

Methods

To identify areas of future CAP research, CAPNETZ followed a multiple-step procedure. First, research members of CAPNETZ were individually asked to identify unmet needs. Second, the top 100 experts in the field of CAP research were asked for their insights about the unmet needs in CAP (Delphi approach). Third, internal and external experts discussed unmet needs in CAP at a scientific retreat.

Results

Eleven topics for future CAP research were identified: detection of causative pathogens, next generation sequencing for antimicrobial treatment guidance, imaging diagnostics, biomarkers, risk stratification, antiviral and antibiotic treatment, adjunctive therapy, vaccines and prevention, systemic and local immune response, comorbidities, and long-term cardio-vascular complications.

Conclusion

Pneumonia is a complex disease where the interplay between pathogens, immune system and comorbidities not only impose an immediate risk of mortality but also affect the patients’ risk of developing comorbidities as well as mortality for up to a decade after pneumonia has resolved. Our review of unmet needs in CAP research has shown that there are still major shortcomings in our knowledge of CAP.

Effect of Pneumococcal Vaccine on Mortality and Cardiovascular Outcomes: A Systematic Review and Meta-Analysis

Various studies have suggested the possible cardiovascular (CV) protective effects of the pneumococcal vaccine (PV). Therefore, we conducted a meta-analysis to assess the association between recipients of PV with mortality and CV outcomes among patients with and without established cardiovascular disease. We performed a systematic literature search in PubMed, Embase, and Scopus for studies evaluating the effect of PV on mortality and CV outcomes. A total of 15 studies with 347,444 patients were included in the meta-analysis: 111,784 patients received PV (32%) and 235,660 patients were in the unvaccinated group (68%). Recipients of PV were associated with decreased all-cause mortality (HR, 0.76 (95% CI: 0.66 to 0.87), p < 0.001). PV was associated with a decrease in the incidence of myocardial infarction (MI) (HR, 0.73 (95% CI: 0.56−0.96), p = 0.02), without significant reduction in CV mortality (HR, 0.87 (95% CI: 0.72−1.07), p = 0.18) and stroke (HR, 1.01 (95% CI: 0.93−1.10), p = 0.82). Our study found PV was associated with decreased risk of all-cause mortality and MI. Future RCTs will be necessary to confirm benefits associated with receipt of PV.

Molecular Approaches for the Validation of the Baboon as a Nonhuman Primate Model for the Study of Zika Virus Infection

Nonhuman primates (NHP) are particularly important for modeling infections with viruses that do not naturally replicate in rodent cells. Zika virus (ZIKV) has been responsible for sporadic epidemics, but in 2015 a disseminated outbreak of ZIKV resulted in the World Health Organization declaring it a global health emergency. Since the advent of this last epidemic, several NHP species, including the baboon, have been utilized for modeling and understanding the complications of ZIKV infection in humans; several health issues related to the outcome of infection have not been resolved yet and require further investigation. This study was designed to validate, in baboons, the molecular signatures that have previously been identified in ZIKV-infected humans and macaque models. We performed a comprehensive molecular analysis of baboons during acute ZIKV infection, including flow cytometry, cytokine, immunological, and transcriptomic analyses. We show here that, similar to most human cases, ZIKV infection of male baboons tends to be subclinical, but is associated with a rapid and transient antiviral interferon-based response signature that induces a detectable humoral and cell-mediated immune response. This immunity against the virus protects animals from challenge with a divergent ZIKV strain, as evidenced by undetectable viremia but clear anamnestic responses. These results provide additional support for the use of baboons as an alternative animal model to macaques and validate omic techniques that could help identify the molecular basis of complications associated with ZIKV infections in humans.

Receptor Interacting Protein Kinases 1/3: The Potential Therapeutic Target for Cardiovascular Inflammatory Diseases

The receptor interacting protein kinases 1/3 (RIPK1/3) have emerged as the key mediators in cell death pathways and inflammatory signaling, whose ubiquitination, phosphorylation, and inhibition could regulate the necroptosis and apoptosis effectually. Recently, more and more studies show great interest in the mechanisms and the regulator of RIPK1/3-mediated inflammatory response and in the physiopathogenesis of cardiovascular diseases. The crosstalk of autophagy and necroptosis in cardiomyocyte death is a nonnegligible conversation of cell death. We elaborated on RIPK1/3-mediated necroptosis, pathways involved, the latest regulatory molecules and therapeutic targets in terms of ischemia reperfusion, myocardial remodeling, myocarditis, atherosclerosis, abdominal aortic aneurysm, and cardiovascular transplantation, etc.

Electrocardiographic abnormalities in COVID-19 patients visiting the emergency department: a multicenter retrospective study

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be associated with myocardial injury. Identification of at-risk patients and mechanisms underlying cardiac involvement in COVID-19 remains unclear. During hospitalization for COVID-19, high troponin level has been found to be an independent variable associated with in-hospital mortality and a greater risk of complications. Electrocardiographic (ECG) abnormalities could be a useful tool to identify patients at risk of poor prognostic. The aim of our study was to assess if specific ECGs patterns could be related with in-hospital mortality in COVID-19 patients presenting to the ED in a European country.

Methods

From February 1st to May 31st, 2020, we conducted a multicenter study in three hospitals in France. We included adult patients (≥ 18 years old) who visited the ED during the study period, with ECG performed at ED admission and diagnosed with COVID-19. Demographic, comorbidities, drug exposures, signs and symptoms presented, and outcome data were extracted from electronic medical records using a standardized data collection form. The relationship between ECG abnormalities and in-hospital mortality was assessed using univariate and multivariable logistic regression analyses.

Results

An ECG was performed on 275 patients who presented to the ED. Most of the ECGs were in normal sinus rhythm (87%), and 26 (10%) patients had atrial fibrillation/flutter on ECG at ED admission. Repolarization abnormalities represented the most common findings reported in the population (40%), with negative T waves representing 21% of all abnormalities. We found that abnormal axis (adjusted odds ratio: 3.9 [95% CI, 1.1–11.5], p = 0.02), and left bundle branch block (adjusted odds ratio: 7.1 [95% CI, 1.9–25.1], p = 0.002) were significantly associated with in-hospital mortality.

Conclusions

ECG performed at ED admission may be useful to predict death in COVID-19 patients. Our data suggest that the presence of abnormal axis and left bundle branch block on ECG indicated a higher risk of in-hospital mortality in COVID-19 patients who presented to the ED. We also confirmed that ST segment elevation was rare in COVID-19 patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-021-00539-8.

Capsule Promotes Intracellular Survival and Vascular Endothelial Cell Translocation during Invasive Pneumococcal Disease

The polysaccharide capsule that surrounds Streptococcus pneumoniae (Spn) is one of its most important virulence determinants, serving to protect against phagocytosis. To date, 100 biochemical and antigenically distinct capsule types, i.e., serotypes, of Spn have been identified. Yet how capsule influences pneumococcal translocation across vascular endothelial cells (VEC), a key step in the progression of invasive disease, was unknown. Here, we show that despite capsule being inhibitory of Spn uptake by VEC, capsule enhances the escape rate of internalized pneumococci and thereby promotes translocation. Upon investigation, we determined that capsule protected Spn against intracellular killing by VEC and H₂O₂-mediated killing in vitro. Using a nitroblue tetrazolium reduction assay and nuclear magnetic resonance (NMR) analyses, purified capsule was confirmed as having antioxidant properties which varied according to serotype. Using an 11-member panel of isogenic capsule-switch mutants, we determined that serotype affected levels of Spn resistance to H₂O₂-mediated killing in vitro, with killing resistance correlated positively with survival duration within VEC, rate of transcytosis to the basolateral surface, and human attack rates. Experiments with mice supported our in vitro findings, with Spn producing oxidative-stress-resistant type 4 capsule being more organ-invasive than that producing oxidative-stress-sensitive type 2 capsule during bacteremia. Capsule-mediated protection against intracellular killing was also observed for Streptococcus pyogenes and Staphylococcus aureus. We conclude that capsular polysaccharide plays an important role within VEC, serving as an intracellular antioxidant, and that serotype-dependent differences in antioxidant capabilities impact the efficiency of VEC translocation and a serotype’s potential for invasive disease.

Development and characterization of a new swine model of invasive pneumococcal pneumonia

Streptococcus pneumoniae is the most common microbial cause of community-acquired pneumonia. Currently, there are no available models of severe pneumococcal pneumonia in mechanically ventilated animals to mimic clinical conditions of critically ill patients. We studied endogenous pulmonary flora in 4 healthy pigs and in an additional 10 pigs in which we intra-bronchially instilled S. pneumoniae serotype 19 A, characterized by its resistance to penicillin, macrolides and tetracyclines. The pigs underwent ventilation for 72 h. All pigs that were not challenged with S. pneumoniae completed the 72-h study, whereas 30% of infected pigs did not. At 24 h, we clinically confirmed pneumonia in the infected pigs; upon necropsy, we sampled lung tissue for microbiological/histological confirmation of pneumococcal pneumonia. In control pigs, Streptococcus suis and Staphylococcus aureus were the most commonly encountered pathogens, and their lung tissue mean ± s.e.m. concentration was 7.94 ± 20 c.f.u./g. In infected pigs, S. pneumoniae was found in the lungs of all pigs (mean ± s.e.m. pulmonary concentration of 1.26 × 10⁵ ± 2 × 10² c.f.u./g). Bacteremia was found in 50% of infected pigs. Pneumococcal pneumonia was confirmed in all infected pigs at 24 h. Pneumonia was associated with thrombocytopenia, an increase in prothrombin time, cardiac output and vasopressor dependency index and a decrease in systemic vascular resistance. Upon necropsy, microbiological/histological pneumococcal pneumonia was confirmed in 8 of 10 pigs. We have therefore developed a novel model of penicillin- and macrolide-resistant pneumococcal pneumonia in mechanically ventilated pigs with bacteremia and severe hemodynamic compromise. The model could prove valuable for appraising the pathogenesis of pneumococcal pneumonia, the effects associated with macrolide resistance and the outcomes related to the use of new diagnostic strategies and antibiotic or complementary therapies.

Community-acquired pneumonia

Community-acquired pneumonia is not usually considered a high-priority problem by the public, although it is responsible for substantial mortality, with a third of patients dying within 1 year after being discharged from hospital for pneumoniae. Although up to 18% of patients with community-acquired pneumonia who were hospitalised (admitted to hospital and treated there) have at least one risk factor for immunosuppression worldwide, strong evidence on community-acquired pneumonia management in this population is scarce. Several features of clinical management for community-acquired pneumonia should be addressed to reduce mortality, morbidity, and complications related to community-acquired pneumonia in patients who are immunocompetent and patients who are immunocompromised. These features include rapid diagnosis, microbiological investigation, prevention and management of complications (eg, respiratory failure, sepsis, and multiorgan failure), empirical antibiotic therapy in accordance with patient's risk factors and local microbiological epidemiology, individualised antibiotic therapy according to microbiological data, appropriate outcomes for therapeutic switch from parenteral to oral antibiotics, discharge planning, and long-term follow-up. This Seminar offers an updated view on community-acquired pneumonia in adults, with suggestions for clinical and translational research.

Major Adverse Cardiovascular Events During Invasive Pneumococcal Disease Are Serotype Dependent

BACKGROUND

Up to 30% of patients admitted to hospitals with invasive pneumococcal disease (IPD) experience major adverse cardiovascular event (MACE) including new/worsening heart failure, new/worsening arrhythmia, and/or myocardial infarction. Streptococcus pneumoniae (Spn) is the most frequently isolated bacterial pathogen among community-acquired pneumonia (CAP) patients and the only etiological agent linked independently to MACE. Nevertheless, no clinical data exist identifying which serotypes of Spn are principally responsible for MACE.

METHODS

This was an observational multicenter retrospective study conducted through the Public Health Secretary of Bogotá, Colombia. We included patients with a confirmed clinical diagnosis of IPD with record of pneumococcal serotyping and clinical information between 2012 and 2019. Spn were serotyped using the quellung method by the National Center of Microbiology. MACE were determined by a retrospective chart review.

RESULTS

The prevalence of MACE was 23% (71/310) in IPD patients and 28% (53/181) in patients admitted for CAP. The most prevalent S. pneumoniae serotype identified in our study was the 19A, responsible for the 13% (42/310) of IPD in our cohort, of which 21% (9/42) presented MACE. Serotypes independently associated with MACE in IPD patients were serotype 3 (odds ratio [OR] 1, 48; 95% confidence interval [CI] [1.21-2.27]; P = .013) and serotype 9n (OR 1.29; 95% CI [1.08-2.24]; P = .020). Bacteremia occurred in 87% of patients with MACE. Moreover, serum concentrations of C-reactive protein were elevated in patients with MACE versus in non-MACE patients (mean [standard deviation], 138 [145] vs 73 [106], P = .01).

CONCLUSIONS

MACE are common during IPD with serotype 3 and 9n independently of frequency.

Non-human primate models of human respiratory infections

Respiratory pathogens represent a great burden for humanity and a potential source of new pandemics, as illustrated by the recent emergence of coronavirus disease 2019 (COVID-19). In recent decades, biotechnological advances have led to the development of numerous innovative therapeutic molecules and vaccine immunogens. However, we still lack effective treatments and vaccines against many respiratory pathogens. More than ever, there is a need for a fast, predictive, preclinical pipeline, to keep pace with emerging diseases. Animal models are key for the preclinical development of disease management strategies. The predictive value of these models depends on their ability to reproduce the features of the human disease, the mode of transmission of the infectious agent and the availability of technologies for monitoring infection. This review focuses on the use of non-human primates as relevant preclinical models for the development of prevention and treatment for human respiratory infections.

Association Between Troponin I Levels During Sepsis and Post-Sepsis Cardiovascular Complications

RATIONALE

Sepsis commonly results in elevated serum troponin I levels and increased risk for post-sepsis cardiovascular complications; however, the association between troponin I level during sepsis and cardiovascular complications after sepsis is unclear.

OBJECTIVES

To evaluate the association between serum troponin levels during sepsis and 1-year post-sepsis cardiovascular risks.

METHODS

We included patients aged >40 years without a prior diagnosis of cardiovascular disease within 5-years, admitted with sepsis across 21 hospitals from 2011 to 2017. Peak serum troponin I levels during sepsis were grouped as normal (<0.04ng/mL) or tertiles of abnormal (>0.04 to <0.09ng/mL, >0.09 to <0.42ng/mL, or >0.42ng/mL). Multivariable adjusted, cause-specific, Cox proportional hazards models that treated death as a competing risk were used to assess associations between peak sepsis troponin I levels and a composite cardiovascular outcome (atherosclerotic cardiovascular disease, atrial fibrillation, and heart failure) in the year following sepsis. Models were adjusted for pre-sepsis and intra-sepsis factors considered potential confounders.

MEASUREMENTS AND MAIN RESULTS

Among 14,046 patients with troponin I measured during sepsis, 2,012 (14.3%) patients experienced the composite cardiovascular outcome in the year following sepsis hospitalization. Compared with patients with normal troponin levels, those with elevated troponins had increased risks of adverse cardiovascular events (adjusted Hazard Ratiotroponin 0.04-0.09=1.37 (95% CI 1.20-1.55), aHRtroponin 0.09-0.42=1.44 (95% CI 1.27-1.63), and aHRtroponin > 0.42=1.77 (95% CI 1.56-2.00)).

CONCLUSIONS

Among patients without pre-existing cardiovascular disease, troponin elevation during sepsis identified patients at increased risk for post-sepsis cardiovascular complications. Strategies to mitigate cardiovascular complications among this high-risk subset of patients is warranted.

[Impact of cardiovascular metabolic diseases on COVID-19: review of recent progress]

The high comorbidity between cardiovascular and metabolic diseases (CVMD) and coronavirus disease 2019 (COVID-19) and the consequent high mortality and the potential risk of cardiovascular damage have brought great challenges to the clinical diagnosis and treatment of the condition. The latest studies found that advanced age, immune function defects, inflammatory factor storms and oxidative stress damage all potentially contribute to the high comorbidity of the two. Direct virus invasion, myocardial oxygen supply and demand imbalance and vascular endothelial and coagulation dysfunction may be important mechanisms for cardiovascular injury in COVID-19 patients. In addition, the expression level of ACE2 (the cell membrane receptor of SARS-CoV-2) in various organs and the peripheral blood not only mediates the direct invasion and damage of the organs, but also participates in regulation of the balance of systematic inflammation and oxidative stress, thus affecting the susceptibility and outcomes of the patients. Herein we review the recent research progress in the comorbidity between COVID-19 and CVMD and explore the mechanisms of cardiovascular damage caused by SARS-CoV-2, thus to provide a theoretical basis for the clinical diagnosis and treatment of COVID-19 with underlying CVMD.

Inhibition of Necroptosis to Prevent Long-term Cardiac Damage During Pneumococcal Pneumonia and Invasive Disease

BACKGROUND

Streptococcus pneumoniae infection can result in bacteremia with devastating consequences including heart damage. Necroptosis is a proinflammatory form of cell death instigated by pore-forming toxins such as S. pneumoniae pneumolysin. Necroptosis-inhibiting drugs may lessen organ damage during invasive pneumococcal disease (IPD).

METHODS

In vitro experiments were carried out with human and mouse cardiomyocytes. Long-term cardiac damage was assessed using high-resolution echocardiography in ampicillin-rescued mice 3 months after challenge with S. pneumoniae. Ponatinib, a necroptosis-inhibiting and Food and Drug Administration-approved drug for lymphocytic leukemia treatment, was administered intraperitoneally alongside ampicillin to test its therapeutic efficacy. Histology of heart sections included hematoxylin-eosin staining for overt damage, immunofluorescence for necroptosis, and Sirius red/fast green staining for collagen deposition.

RESULTS

Cardiomyocyte death and heart damage was due to pneumolysin-mediated necroptosis. IPD leads to long-term cardiac damage, as evidenced by de novo collagen deposition in mouse hearts and a decrease in fractional shortening. Adjunct necroptosis inhibition reduced the number of S. pneumoniae foci observed in hearts of acutely infected mice and serum levels of troponin I. Ponatinib reduced collagen deposition and protected heart function in convalescence.

CONCLUSIONS

Acute and long-term cardiac damage incurred during IPD is due in part to cardiomyocyte necroptosis. Necroptosis inhibitors may be a viable adjunct therapy.

Infection, atherothrombosis and thromboembolism beyond the COVID-19 disease: what similar in physiopathology and researches

The recent Sars-Cov-2 pandemic (COVID-19) has led to growing research on the relationship between thromboembolism and Sars-Cov-2 infection. Nowadays, endothelial dysfunction, platelet activation, coagulation, and inflammatory host immune response are the subject of extensive researches in patients with COVID-19 disease. However, studies on the link between microorganisms or infections and thrombotic or thromboembolic events met fluctuating interest in the past. We, therefore, aimed to briefly summarize previous evidence on this topic, highlighting common points between previous data and what experienced today with SARS-COV2 infections.

New-onset atrial fibrillation in patients with pneumococcal pneumonia. Impact of timing and duration on short- and medium-term mortality

OBJETIVES

To assess the incidence, related factors, timing and duration of new- onset atrial fibrillation in a cohort of consecutive patients diagnosed with pneumococcal pneumonia.

METHODS

Observational study including all immunocompetent adults hospitalized for pneumococcal pneumonia. Patients were classified by time (atrial fibrillation recognized on emergency room arrival or developed during hospitalization) and duration (paroxysmal or persistent). Patients were followed-up for 6 months after discharge.

RESULTS

We included 1092 patients, of whom 109 (9.9%) had new-onset atrial fibrillation. An early event was documented in 87 (79.8%) cases. Arrhythmia was classified as paroxysmal in 78 patients. Older age, heavy drinking, respiratory rate ≥ 30/minute, leukopenia, severe inflammation and bacteremia were independent risk factors for developing new-onset atrial fibrillation on admission. Overall, 48 (4.4%) patients died during hospitalization, the rate being higher in those patients who developed new-onset arrhythmia (17.9% vs 2.9% p<0.001). Among patients with events recognized at admission, in-hospital mortality was higher in those with persistent arrhythmia (34.8% vs 6.3%, p = 0.002) and 6-month survival was better among those who developed paroxysmal event.

CONCLUSIONS

The development of new-onset atrial fibrillation was associated with pneumonia severity, and higher in-hospital mortality. Bacteremia and severe systemic inflammation were factors associated with its development.

Host- and Pathogen-Related Factors for Acute Cardiac Events in Pneumococcal Pneumonia

Background

Acute cardiac events (ACEs) are increasingly being recognized as a major complication in pneumococcal community-acquired pneumonia (CAP). Information regarding host- and pathogen-related factors for ACEs, including pneumococcal serotypes and clonal complexes, is scarce.

Methods

A retrospective study was conducted of a prospective cohort of patients hospitalized for CAP between 1996 and 2019. Logistic regression and funnel plot analyses were performed to determine host- and pathogen-related factors for ACEs.

Results

Of 1739 episodes of pneumococcal CAP, 1 or more ACEs occurred in 304 (17.5%) patients, the most frequent being arrhythmia (n = 207), heart failure (n = 135), and myocardial infarction (n = 23). The majority of ACEs (73.4%) occurred within 48 hours of admission. Factors independently associated with ACEs were older age, preexisting heart conditions, pneumococcal bacteremia, septic shock at admission, and high-risk pneumonia. Among 983 pneumococcal isolates, 872 (88.7%) were serotyped and 742 (75.5%) genotyped. The funnel plot analyses did not find any statistically significant association between serotypes or clonal complexes with ACEs. Nevertheless, there was a trend toward an association between CC230 and these complications. ACEs were independently associated with 30-day mortality (adjusted odds ratio, 1.88; 95% CI, 1.11-3.13).

Conclusions

ACEs are frequent in pneumococcal pneumonia and are associated with increased mortality. The risk factors defined in this study may help identify patients who must undergo close follow-up, including heart rhythm monitoring, and special care to avoid fluid overload, particularly during the first 48 hours of admission. These high-risk patients should be the target for preventive intervention strategies.

Perspective of a Pediatrician: Shared Pathogenesis of the Three Most Successful Pathogens of Children

Highly successful invasive pathogens exploit host vulnerabilities by adapting tools to co-opt highly conserved host features. This is especially true when pathogens develop ligands to hijack trafficking routes or signaling patterns of host receptors. In this context, highly successful pathogens can be grouped together by the patterns of organs infected and diseases they cause. In the case of this perspective, the focus is on the historically most successful invasive bacterial pathogens of children that cause pneumonia, sepsis and meningitis: Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis. This triad shares a ligand to bind to PAF receptor to enter host cells despite early defenses by innate immunity. All three also target laminin receptor to cross endothelial barriers using a common set of molecular tools that may prove to be a design for a cross-protective vaccine.

Effectiveness and safety of pneumococcal vaccines used alone or combined with influenza vaccination in dialysis patients: A systematic review and meta-analysis

BACKGROUND

A lower conversion vaccination rate and a more rapid decline in antibody titers over time in dialysis patients raise concerns about the effectiveness of pneumococcal vaccination (PV) in this population, which has not been systematically reviewed.

METHODS

We searched PubMed, Cochrane Library, Embase and three Chinese databases from inception until February 29th, 2020 for interventional, cohort and case-control studies evaluating PV alone or combined with influenza vaccination (IV) on outcomes (all-cause mortality, pneumonia, cardiovascular events, antibody response and safety). Independent reviewers completed citation screening, data extraction, risk assessment, meta-analysis, and GRADE rating of the quality of evidence.

RESULTS

Five cohort studies and one quasirandomized control trial enrolling 394,299 dialysis patients with high to moderate quality were included. Compared with unvaccinated individuals, those receiving PV had lower risk of all-cause mortality [Adjusted relative risk (RR) 0.73, 95% CI 0.67-0.79, I² = 31.1%, GRADE low certainty] and cardiovascular events (adjusted RR 0.80, 95% CI 0.69-0.93, I² = 47.2%, GRADE low certainty) without serious adverse effect reported. Compared with no vaccination, lower all-cause mortality was observed in those receiving PV combined with IV (Adjusted RR 0.71, 95%CI 0.67-0.75, I² = 63.3%), PV alone (Adjusted RR 0.86, 95% CI 0.78-0.94,I² = 0%], and IV alone (Adjusted RR 0.76, 95% CI 0.73-0.79, I² = 0%]. There was no difference between pneumococcal vaccinated patients vs non-vaccinated patients with respect to pneumonia. Immune response to pneumococcal conjugate vaccine-13 was weaker in polysaccharide pneumococcal vaccine-23-pre-vaccinated compared with vaccine-naive patients.

CONCLUSIONS

The use of pneumococcal vaccine especially combined with influenza vaccination is associated with lower risks of all-cause mortality but may be affected by residual confounding/healthy vaccinee bias.

Cardiac Microlesions Form During Severe Bacteremic Enterococcus faecalis Infection

Enterococcus  faecalis is a significant cause of hospital-acquired bacteremia. Herein, the discovery is reported that cardiac microlesions form during severe bacteremic E. faecalis infection in mice. The cardiac microlesions were identical in appearance to those formed by Streptococcus pneumoniae during invasive pneumococcal disease. However, E. faecalis does not encode the virulence determinants implicated in pneumococcal microlesion formation. Rather, disulfide bond forming protein A (DsbA) was found to be required for E. faecalis virulence in a Caenorhabditis elegans model and was necessary for efficient cardiac microlesion formation. Furthermore, E. faecalis promoted cardiomyocyte apoptotic and necroptotic cell death at sites of microlesion formation. Additionally, loss of DsbA caused an increase in proinflammatory cytokines, unlike the wild-type strain, which suppressed the immune response. In conclusion, we establish that E. faecalis is capable of forming cardiac microlesions and identify features of both the bacterium and the host response that are mechanistically involved.

Cardiac complications in community-acquired pneumonia and COVID-19

Community-acquired pneumonia (CAP) remains a global health problem with significant morbidity and mortality. Much recent published literature about the infection has indicated that a substantial number of patients with CAP, particularly those ill enough to be admitted to hospital, will suffer a cardiovascular event. While these may include events such as deep venous thrombosis and stroke, most of the events involve the heart and include the occurrence of an arrhythmia (most commonly atrial fibrillation), new onset or worsening of heart failure and acute myocardial infarction. While such cardiac events may occur, for example, in all-cause CAP and CAP due to influenza virus infection, and more recently described with the SARS-CoV-2 pandemic, a significant amount of research work has been investigating the pathogenic mechanisms of these cardiac events in patients with CAP due to Streptococcus pneumoniae (pneumococcus) and, more recently, COVID-19 infections. Such research has identified a number of mechanisms by which these microorganisms may cause cardiovascular events. Importantly, these cardiac events appear not only to be associated with in-hospital mortality, but they also appear to contribute to longer-term mortality of patients with CAP, even after their discharge from hospital. This review will focus initially on studies of cardiovascular events in all-cause CAP and pneumococcal CAP, excluding COVID-19 infection, and then address similar issues in the latter infection.

Community-acquired pneumonia in critically ill very old patients: a growing problem

Very old (aged ≥80 years) adults constitute an increasing proportion of the global population. Currently, this subgroup of patients represents an important percentage of patients admitted to the intensive care unit. Community-acquired pneumonia (CAP) frequently affects very old adults. However, there are no specific recommendations for the management of critically ill very old CAP patients. Multiple morbidities, polypharmacy, immunosenescence and frailty contribute to an increased risk of pneumonia in this population. CAP in critically ill very old patients is associated with higher short- and long-term mortality; however, because of its uncommon presentation, diagnosis can be very difficult. Management of critically ill very old CAP patients should be guided by their baseline characteristics, clinical presentation and risk factors for multidrug-resistant pathogens. Hospitalisation in intermediate care may be a good option for critical ill very old CAP patients who do not require invasive procedures and for whom intensive care is questionable in terms of benefit.

There is currently no international recommendation for the management of critically ill older patients over 80 years of age with CAP. We report and discuss recent literature in order to help physicians in the decision-making process of these patients.http://bit.ly/2ql0mIz