Initial Inflammatory Profile in Community-acquired Pneumonia Depends on Time since Onset of Symptoms

Biomarkers: Are They Useful in Severe Community-Acquired Pneumonia?

Community acquired pneumonia (CAP) is a prevalent infectious disease often requiring hospitalization, although its diagnosis remains challenging as there is no gold standard test. In severe CAP, clinical and radiologic criteria have poor sensitivity and specificity, and microbiologic documentation is usually delayed and obtained in less than half of sCAP patients. Biomarkers could be an alternative for diagnosis, treatment monitoring and establish resolution. Beyond the existing evidence about biomarkers as an adjunct diagnostic tool, most evidence comes from studies including CAP patients in primary care or emergency departments, and not only sCAP patients. Ideally, biomarkers used in combination with signs, symptoms, and radiological findings can improve clinical judgment to confirm or rule out CAP diagnosis, and may be valuable adjunctive tools for risk stratification, differentiate viral pneumonia and monitoring the course of CAP. While no single biomarker has emerged as an ideal one, CRP and PCT have gathered the most evidence. Overall, biomarkers offer valuable information and can enhance clinical decision-making in the management of CAP, but further research and validation are needed to establish their optimal use and clinical utility.

Treatment Failure and Clinical Stability in Severe Community-Acquired Pneumonia

Treatment failure and clinical stability are important outcomes in community-acquired pneumonia (CAP). It is essential to know the causes and risk factors for treatment failure and delay in reaching clinical stability in CAP. The study of both as well as the associated underlying mechanisms and host response are key to improving outcomes in pneumonia.

Procalcitonin and C-reactive protein to rule out early bacterial coinfection in COVID-19 critically ill patients

PURPOSE

Although the prevalence of community-acquired respiratory bacterial coinfection upon hospital admission in patients with coronavirus disease 2019 (COVID-19) has been reported to be < 5%, almost three-quarters of patients received antibiotics. We aim to investigate whether procalcitonin (PCT) or C-reactive protein (CRP) upon admission could be helpful biomarkers to identify bacterial coinfection among patients with COVID-19 pneumonia.

METHODS

We carried out a multicentre, observational cohort study including consecutive COVID-19 patients admitted to 55 Spanish intensive care units (ICUs). The primary outcome was to explore whether PCT or CRP serum levels upon hospital admission could predict bacterial coinfection among patients with COVID-19 pneumonia. The secondary outcome was the evaluation of their association with mortality. We also conducted subgroups analyses in higher risk profile populations.

RESULTS

Between 5 February 2020 and 21 December 2021, 4076 patients were included, 133 (3%) of whom presented bacterial coinfection. PCT and CRP had low area under curve (AUC) scores at the receiver operating characteristic (ROC) curve analysis [0.57 (95% confidence interval (CI) 0.51-0.61) and 0.6 (95% CI, 0.55-0.64), respectively], but high negative predictive values (NPV) [97.5% (95% CI 96.5-98.5) and 98.2% (95% CI 97.5-98.9) for PCT and CRP, respectively]. CRP alone was associated with bacterial coinfection (OR 2, 95% CI 1.25-3.19; p = 0.004). The overall 15, 30 and 90 days mortality had a higher trend in the bacterial coinfection group, but without significant difference. PCT ≥ 0.12 ng/mL was associated with higher 90 days mortality.

CONCLUSION

Our study suggests that measurements of PCT and CRP, alone and at a single time point, are not useful for ruling in or out bacterial coinfection in viral pneumonia by COVID-19.

The association between serum complement C3a and severity in patients with community-acquired pneumonia

Background

A few studies found that the complement system may be involved in the onset and progression of community-acquired pneumonia (CAP). However, the role of the complement system in CAP was obscure. The goal of this study was to analyze the association of serum complement C3a with CAP severity scores based on a cross-sectional study.

Methods

All 190 CAP patients and 95 control subjects were enrolled. Demographic information and clinical data were extracted. Peripheral blood samples were collected on admission.

Results

Serum complement C3a on admission was elevated in CAP patients compared with healthy subjects. The level of complement C3a was gradually elevated in parallel with CAP severity scores (CURB-65, CRB-65, PSI, SMART-COP, and CURXO). Complement C3a was positively correlated with blood routine parameters, renal function markers, and inflammatory cytokines in CAP patients. Furthermore, multivariate linear and logistic regression models found that serum complement C3a on admission was positively associated with CAP severity scores. Mechanistic research suggested that complement system inhibition alleviated Streptococcus pneumoniae-induced upregulation of IL-1β, TNF-α, IL-6, and CRP in MLE-12 cells.

Conclusions

Serum complement C3a on admission is positively associated with the severity of CAP patients. Inhibiting complement system attenuates S. pneumoniae-elevated secretion of inflammatory cytokines in pulmonary epithelial cells, indicating that complement C3a is involved in the pathophysiology of CAP. Serum complement C3a may serve as an earlier diagnostic biomarker for CAP.

Severe community-acquired pneumonia

Severe community-acquired pneumonia is the most life-threatening form of community-acquired pneumonia, characterised by intensive care unit admission and high morbidity and mortality. In this review article, we cover in depth six aspects of severe community-acquired pneumonia that are still controversial: use of PCR molecular techniques for microbial diagnosis; the role of biomarkers for initial management; duration of treatment, macrolides or quinolones in the initial empirical antibiotic therapy; the use of prediction scores for drug-resistant pathogens to modify initial empiric therapy; the use of noninvasive mechanical ventilation and high-flow nasal oxygen; and the use of corticosteroids as adjunctive therapy in severe community-acquired pneumonia.

Performance of host-response biomarkers to risk-stratify children with pneumonia in Bhutan

Pneumonia is the leading cause of post-neonatal death amongst children under five years of age; however, there is no simple triage tool to identify children at risk of progressing to severe and fatal disease. Such a tool could assist for early referral and prioritization of care to improve outcomes and enhance allocation of scarce resources. We compared the performance of inflammatory and endothelial activation markers in addition to clinical signs or scoring scales to risk-stratify children hospitalized with pneumonia at the national referral hospital of Bhutan with the goal of predicting clinical outcome. Of 118 children, 31 evolved to a poor prognosis, defined as either mortality, admission in the paediatric intensive care unit, requirement of chest drainage or requirement of more than five days of oxygen therapy. Soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) was the best performing biomarker and performed better than clinical parameters. sTREM-1 levels upon admission had good predictive accuracy to identify children with pneumonia at risk of poor prognosis. Our findings confirm that immune and endothelial activation markers could be proactively used at first encounter as risk-stratification and clinical decision-making tools in children with pneumonia; however, further external validation is needed.

Clinical profile analysis and nomogram for predicting in-hospital mortality among elderly severe community-acquired pneumonia patients with comorbid cardiovascular disease: a retrospective cohort study

Background

Researchers have linked cardiovascular disease (CVD) with advancing age; however, how it drives disease progression in elderly severe community acquired pneumonia (SCAP) patients is still unclear. This study aims to identify leading risk predictors of in-hospital mortality in elderly SCAP patients with CVD, and construct a comprehensive nomogram for providing personalized prediction.

Patients and methods

The study retrospectively enrolled 2365 elderly patients identified SCAP. Among them, 413 patients were found to have CVD. The LASSO regression and multivariate logistic regression analysis were utilized to select potential predictors of in-hospital mortality in elderly SCAP patients with CVD. By incorporating these features, a nomogram was then developed and subjected to internal validations. Discrimination, calibration, and clinical use of the nomogram were assessed via C-index, calibration curve analysis, and decision plot.

Results

Compared with patients without CVD, elderly SCAP patients with CVD had a significant poor outcome. Further analysis of the CVD population identified 7 independent risk factors for in-hospital mortality in elderly SCAP patients, including age, the use of vasopressor, numbers of primary symptoms, body temperature, monocyte, CRP and NLR. The nomogram model incorporated these 7 predictors showed sufficient predictive accuracy, with the C-index of 0.800 (95% CI 0.758–0.842). High C-index value of 0.781 was obtained in the internal validation via bootstrapping validation. Moreover, the calibration curve indicative a good consistency of risk prediction, and the decision curve manifested that the nomogram had good overall net benefits.

Conclusion

An integrated nomogram was developed to facilitate the personalized prediction of in-hospital mortality in elderly SCAP patients with CVD.

Diagnostic Value and Prognostic Significance of Procalcitonin Combined with C-Reactive Protein in Patients with Bacterial Bloodstream Infection

Objective

To study the clinical values and implications for the prognosis of procalcitonin (PCT) combined with C-reactive protein (hs-CRP) in patients with bacterial bloodstream infection.

Methods

One hundred and twenty patients with infection hospitalized from Mar. 2020 to Jun. 2021 were chosen as subjects. All participants were tested for serum PCT, hs-CRP, and blood culture. According to the types of pathogenic bacteria, they were divided into the gram-negative bacteria bloodstream infection group (n = 53) and the gram-positive bacteria bloodstream infection group (n = 31). Depending on the prognostic outcome of the participants after 28 days, they were categorized into survival and fatality cohorts. The PCT and hs-CRP levels were compared to explore diagnostic value implications for the prognosis of the cases with bacterial bloodstream infection.

Results

Serum PCT and hs-CRP values in the positive cohort were higher than those in the negative cohort. The levels of serum PCT and hs-CRP in pulmonary infection were higher than those in the group with negative cases, and the difference was statistically significant (P < 0.05). There were 27 gram-positive participants and 9 gram-negative cases in the positive cohort. The serum PCT value of gram-negative bacterial infection was greater than that of gram-positive bacterial infection. The value of serum PCT in the gram-negative bacterial infection group was higher than that in the gram-positive bacterial infection group, and the difference was statistically significant (P < 0.05). The areas under the curve (AUCs) of PCT, combination of hs-CRP and PCT, and hs-CRP were 0.946, 0.783, and 0.991, respectively. The combined examination of PCT and hs-CRP was the largest, PCT was the second, and hs-CRP was the lowest. These results indicated that the accuracy of combined detection of PCT and hs-CRP in the diagnostic bloodstream infection was the highest (0.991), followed by PCT (0.946) and the lowest (0.783). The PCT and hs-CRP levels of the survival cohort were lower than those in the death cohort. AUCs of PCT, hs-CRP and PCT, and hs-CRP were 0.848, 0.826, and 0.934, respectively. The combined examination of PCT and hs-CRP was the largest, followed by PCT and hs-CRP. The accuracy of the combination of PCT and hs-CRP was the highest (0.934), followed by PCT (0.848), and the diagnostic accuracy of hs-CRP was the lowest (0.826).

Conclusion

There were significant differences in the levels of PCT and CRP between the gram-positive bacteria group and the gram-positive bacteria group. PCT and CRP have high diagnostic values in predicting the short-term prognosis of patients. PCT and CRP assist clinical diagnosis and guide treatment and play a positive role in early treatment and prognosis evaluation of patients.

Multi-drug resistant gram-negative bacterial pneumonia: etiology, risk factors, and drug resistance patterns

Bacterial pneumonia is one of the most serious public health issues owing to its medical and economic costs, which result in increased morbidity and mortality in people of all ages around the world. Furthermore, antimicrobial resistance has risen over time, and the advent of multi-drug resistance in GNB complicates therapy and has a detrimental impact on patient outcomes. The current review aimed to summarize bacterial pneumonia with an emphasis on gram-negative etiology, pathogenesis, risk factors, resistance mechanisms, treatment updates, and vaccine concerns to tackle the problem before it causes a serious consequence. In conclusion, the global prevalence of GNB in CAP was reported 49.7% to 83.1%, whereas in VAP patients ranged between 76.13% to 95.3%. The most commonly reported MDR-GNB causes of pneumonia were A. baumannii, K. pneumoniae, and P. aeruginosa, with A. baumannii isolated particularly in VAP patients and the elderly. In most studies, ampicillin, tetracyclines, amoxicillin-clavulanic acid, cephalosporins, and carbapenems were shown to be highly resistant. Prior MDR-GNB infection, older age, previous use of broad-spectrum antibiotics, high frequency of local antibiotic resistance, prolonged hospital stays, ICU admission, mechanical ventilation, and immunosuppression are associated with the MDR-GNB colonization. S. maltophilia was reported as a severe cause of HAP/VAP in patients with mechanically ventilated and having hematologic malignancy due to its ability of biofilm formation, site adhesion in respiratory devices, and its intrinsic and acquired drug resistance mechanisms. Effective combination therapies targeting PDR strains and drug-resistant genes, antibiofilm agents, gene-based vaccinations, and pathogen-specific lymphocytes should be developed in the future.

Use of infection biomarkers in the emergency department

The use of infection biomarkers in the emergency department is discussed in terms of their possible contributions to diagnostic-prognostic uncertainties, appropriate antibiotic treatments, and triage and follow-up planning. Procalcitonin (PCT), C-reactive protein (CRP), proadrenomedullin (proADM), and presepsin are among the most discussed infection biomarkers for use in the emergency department. Due to the variable sensitivity results and cutoff values, there are insufficient data to recommend the widespread use of CRP and procalcitonin (PCT) for the diagnosis and prognosis of infection in the emergency department. However, these biomarkers can be used for appropriate antibiotic use in selected infection groups, such as community-acquired pneumonia, especially to reduce unnecessary antibiotic prescribing. With its prognostic superiority over other biomarkers and its contribution to prognostic score systems in community-acquired pneumonia (CAP), proADM can be used to predict hospitalization, preferably within the scope of clinical studies. Although presepsin has been shown to have some advantages over other biomarkers to rule out sepsis, there are insufficient data for its clinical use in the emergency department.

Management of pneumonia in critically ill patients

Severe pneumonia is associated with high mortality (short and long term), as well as pulmonary and extrapulmonary complications. Appropriate diagnosis and early initiation of adequate antimicrobial treatment for severe pneumonia are crucial in improving survival among critically ill patients. Identifying the underlying causative pathogen is also critical for antimicrobial stewardship. However, establishing an etiological diagnosis is challenging in most patients, especially in those with chronic underlying disease; those who received previous antibiotic treatment; and those treated with mechanical ventilation. Furthermore, as antimicrobial therapy must be empiric, national and international guidelines recommend initial antimicrobial treatment according to the location's epidemiology; for patients admitted to the intensive care unit, specific recommendations on disease management are available. Adherence to pneumonia guidelines is associated with better outcomes in severe pneumonia. Yet, the continuing and necessary research on severe pneumonia is expansive, inviting different perspectives on host immunological responses, assessment of illness severity, microbial causes, risk factors for multidrug resistant pathogens, diagnostic tests, and therapeutic options.

Burden of pneumococcal disease among adults in Southern Europe (Spain, Portugal, Italy, and Greece): a systematic review and meta-analysis

The aim was to summarize pneumococcal disease burden data among adults in Southern Europe and the potential impact of vaccines on epidemiology. Of 4779 identified studies, 272 were selected. Invasive pneumococcal disease (IPD) incidence was 15.08 (95% CI 11.01-20.65) in Spain versus 2.56 (95% CI 1.54-4.24) per 100,000 population in Italy. Pneumococcal pneumonia incidence was 19.59 (95% CI 10.74-35.74) in Spain versus 2.19 (95% CI 1.36-3.54) per 100,000 population in Italy. Analysis of IPD incidence in Spain comparing pre-and post- PCV7 and PCV13 periods unveiled a declining trend in vaccine-type IPD incidence (larger and statistically significant for the elderly), suggesting indirect effects of childhood vaccination programme. Data from Portugal, Greece and, to a lesser extent, Italy were sparse, thus improved surveillance is needed. Pneumococcal vaccination uptake, particularly among the elderly and adults with chronic and immunosuppressing conditions, should be improved, including shift to a higher-valency pneumococcal conjugate vaccine when available.

Association between delay in intensive care unit admission and the host response in patients with community-acquired pneumonia

Background

A delay in admission to the intensive care unit (ICU) of patients with community-acquired pneumonia (CAP) has been associated with an increased mortality. Decisions regarding interventions and eligibility for immune modulatory therapy are often made at the time of admission to the ICU. The primary aim of this study was to compare the host immune response measured upon ICU admission in CAP patients admitted immediately from the emergency department (direct ICU admission) with those who were transferred within 72 h after admission to the general ward (delayed ICU admission).

Methods

Sixteen host response biomarkers providing insight in pathophysiological mechanisms implicated in sepsis and blood leukocyte transcriptomes were analysed in patients with CAP upon ICU admission in two tertiary hospitals in the Netherlands.

Results

Of 530 ICU admissions with CAP, 387 (73.0%) were directly admitted and 143 (27.0%) had a delayed admission. Patients with a delayed ICU admission were more often immunocompromised (35.0 versus 21.2%, P = .002) and had more malignancies (23.1 versus 13.4%, P = .011). Shock was more present in patients who were admitted to the ICU directly (46.6 versus 33.6%, P = .010). Delayed ICU admission was not associated with an increased hospital mortality risk (hazard ratio 1.25, 95% CI 0.89–1.78, P = .20). The plasma levels of biomarkers (n = 297) reflecting systemic inflammation, endothelial cell activation and coagulation activation were largely similar between groups, with exception of C-reactive protein, soluble intercellular adhesion molecule-1 and angiopoietin-1, which were more aberrant in delayed admissions compared to direct ICU admissions. Blood leukocyte transcriptomes (n = 132) of patients with a delayed ICU admission showed blunted innate and adaptive immune response signalling when compared with direct ICU admissions, as well as decreased gene expression associated with tissue repair and extracellular matrix remodelling pathways.

Conclusions

Blood leukocytes of CAP patients with delayed ICU admission show evidence of a more immune suppressive phenotype upon ICU admission when compared with blood leukocytes from patients directly transferred to the ICU.

Trial registration: Molecular Diagnosis and Risk Stratification of Sepsis (MARS) project, ClinicalTrials.gov identifier NCT01905033.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00930-5.

The therapeutic effects of naringenin on bronchial pneumonia in children

Bronchial pneumonia in children is a common infectious disease in toddlers and infants, which may cause hyperpyrexia, pulmonary moist rales, and even respiratory failure. Traditional drugs for bronchial pneumonia in children often lead to drug resistance and side effects. Recently, naringenin has been reported to be a potential treatment for several airway inflammatory diseases due to its anti-inflammatory and anti-microbial activities. The current clinical study aimed to evaluate the safety and therapeutic effect of naringenin in treating bronchial pneumonia in children. A total of 180 eligible patients were randomly assigned into naringenin (NAR) group and azithromycin (AZI) group. All participants were required to follow a 5-day oral administration, and their serum cytokine levels were measured during the clinical intervention. After the treatment, the disappearance time of clinical symptoms, and the incidences of complications and adverse reactions were compared between the two groups. Naringenin was able to inhibit inflammation, shorten the disappearance time of clinical symptoms, reduce the incidences of bronchial pneumonia complications and related adverse reactions, and improve the health conditions of the patients. Our results suggested that naringenin was safe and beneficial to children with bronchial pneumonia, providing new insights into the clinical application of naringenin.

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.

Antimicrobial Stewardship in the Intensive Care Unit: The Role of Biomarkers, Pharmacokinetics, and Pharmacodynamics

The high prevalence of infectious diseases in the intensive care unit (ICU) and consequently elevated pressure for immediate and effective treatment have led to increased antimicrobial therapy consumption and misuse. Moreover, the emerging global threat of antimicrobial resistance and lack of novel antimicrobials justify the implementation of judicious antimicrobial stewardship programs (ASP) in the ICU. However, even though the importance of ASP is generally accepted, its implementation in the ICU is far from optimal and current evidence regarding strategies such as de-escalation remains controversial. The limitations of clinical guidance for antimicrobial therapy initiation and discontinuation have led to multiple studies for the evaluation of more objective tools, such as biomarkers as adjuncts for ASP. C-reactive protein and procalcitonin can be adequate for clinical use in acute infectious diseases, the latter being the most studied for ASP purposes. Although promising, current evidence highlights challenges in biomarker application and interpretation. Furthermore, the physiological alterations in the critically ill render pharmacokinetics and pharmacodynamics crucial parameters for adequate antimicrobial therapy use. Individual pharmacokinetic and pharmacodynamic targets can reduce antimicrobial therapy misuse and risk of antimicrobial resistance.

Biomarkers in Community-Acquired Pneumonia (Cardiac and Non-Cardiac)

Community-acquired pneumonia (CAP) remains the first cause of morbidity and mortality worldwide due to infection. Several aspects such as severity and host response are related to its clinical course and outcome. Beyond the acute implications that the infection provokes in the host, pneumonia also has long-term negative consequences. Among them, cardiovascular complications and mortality are the most outstanding. Therefore, an adequate recognition and stratification of the risk of complications and mortality is crucial. Many biomarkers have been studied for these reasons, considering that each biomarker mirrors a different aspect. Moreover, the clinical application of many of them is still being deliberated because of their limitations and the heterogeneity of the disease. In this review, we examine some of the most relevant biomarkers that we have classified as cardiac and non-cardiac. We discuss some classic biomarkers and others that are considered novel biomarkers, which are mainly involved in cardiovascular risk.

Molecular Diagnostics in Pulmonary Infections

Infection of the lung parenchyma, or pneumonia, accounts for over four million deaths per year worldwide (Ferkol and Schraufnagel, Ann Am Thorac Soc 11:404–406, 2014). The condition is common, but also over-diagnosed, in part due to relatively poor laboratory and radiographic diagnostics. Indeed, we continue to rely on antiquated tools such as sputum culture and chest X-ray – the former of which lacks speed and sensitivity, and the latter specificity (Albaum et al. Chest 110:343–50, 1996). The resulting presumptive diagnoses of pneumonia lead to excessive use of empiric broad spectrum antibiotics; indeed, by some estimates, 30–70% of antibiotic prescriptions for lower respiratory tract infection are inappropriate (Kraus, PLoS One 12(3): e0174584, 2017). This approach begets microbial resistance, exposes patients to medication side effects, and puts patients at risk of potentially life-threatening complications including Clostridium difficile colitis.

To improve diagnostic certainty in patients with suspected pneumonia, we must begin to consider and implement emerging technologies for efficient and accurate characterization of host responses to infection and identification of pathogens. In this chapter, we will discuss precision diagnostics already in common practice and those poised to be, and how these tools may ultimately enable personalization in the diagnosis of pneumonia.

Effect of Corticosteroids on C-Reactive Protein in Patients with Severe Community-Acquired Pneumonia and High Inflammatory Response: The Effect of Lymphopenia

Background: Lymphopenic patients with community-acquired pneumonia (CAP) have shown high mortality rates. Corticosteroids have immunomodulatory properties and regulate cytokine storm in CAP. However, it is not known whether their modulatory effect on cytokine secretion differs in lymphopenic and non-lymphopenic patients with CAP. Therefore, we aimed to test whether the presence of lymphopenia may modify the response to corticosteroids (mainly in C reactive protein (CRP)) in patients with severe CAP and high inflammatory status). Methods: A post hoc analysis of a randomized controlled trial (NCT00908713) which evaluated the effect of corticosteroids in patients with severe CAP and high inflammatory response (CRP > 15 mg/dL). Patients were clustered according to the presence of lymphopenia (lymphocyte count below 1000 cell/mm³). Results: At day 1, 35 patients (59%) in the placebo group presented with lymphopenia, compared to 44 patients (73%) in the corticosteroid group. The adjusted mean changes from day 1 showed an increase of 1.19 natural logarithm (ln) cell/mm³ in the corticosteroid group and an increase of 0.67 ln cell/mm³ in the placebo group (LS mean difference of the changes in ln (methylprednisolone minus placebo) 0.51, 95% CI (0.02 to 1.01), p = 0.043). A significant effect was also found for the interaction (p = 0.043) between corticosteroids and lymphopenia in CRP values at day 3, with lower values in patients without lymphopenia receiving corticosteroids after adjustments for potential confounders. Conclusion: In this exploratory post hoc analysis from ramdomized controlled trial (RCT) data, the response to corticosteroids, measured by CRP, may differ according to lymphocyte count. Further larger studies are needed to confirm this data.

Diagnosis and treatment of acute pulmonary inflammation in critically ill patients: The role of inflammatory biomarkers

Pneumonia and acute respiratory distress syndrome are common and important causes of respiratory failure in the intensive care unit with a significant impact on morbidity, mortality and health care utilization despite early antimicrobial therapy and lung protective mechanical ventilation. Both clinical entities are characterized by acute pulmonary inflammation in response to direct or indirect lung injury. Adjunct anti-inflammatory treatment with corticosteroids is increasingly used, although the evidence for benefit is limited. The treatment decisions are based on radiographic, clinical and physiological variables without regards to inflammatory state. Current evidence suggests a role of biomarkers for the assessment of severity, and distinguishing sub-phenotypes (hyper-inflammatory versus hypo-inflammatory) with important prognostic and therapeutic implications. Although many inflammatory biomarkers have been studied the most common and of interest are C-reactive protein, procalcitonin, and pro-inflammatory cytokines including interleukin 6. While extensively studied as prognostic tools (prognostic enrichment), limited data are available for the role of biomarkers in determining appropriate initiation, timing and dosing of adjunct anti-inflammatory treatment (predictive enrichment).

Biomarkers of Community-Acquired Pneumonia: A Key to Disease Diagnosis and Management

Community-acquired pneumonia (CAP) is a dangerous disease caused by a spectrum of bacterial and viral pathogens. The choice of specific therapy and the need for hospitalization or transfer to the intensive care unit are determined by the causative agent and disease severity. The microbiological analysis of sputum largely depends on the quality of the material obtained. The prediction of severity and the duration of therapy are determined individually, and existing prognostic scales are used generally. This review examines the possibilities of using specific serological biomarkers to detect the bacterial or viral aetiology of CAP and to assess disease severity. Particular emphasis is placed on the use of biomarker signatures and the discovery of biomarker candidates for a single multiplex analysis.

Challenges in severe community-acquired pneumonia: a point-of-view review

Purpose

Severe community-acquired pneumonia (SCAP) is still associated with substantial morbidity and mortality. In this point-of-view review paper, a group of experts discuss the main controversies in SCAP: the role of severity scores to guide patient settings of care and empiric antibiotic therapy; the emergence of pathogens outside the core microorganisms of CAP; viral SCAP; the best empirical treatment; septic shock as the most lethal complication; and the need for new antibiotics.

Methods

For all topics, the authors describe current controversies and evidence and provide recommendations and suggestions for future research. Evidence was based on meta-analyses, most recent RCTs and recent interventional or observational studies. Recommendations were reached by consensus of all the authors.

Results and conclusions

The IDSA/ATS criteria remain the most pragmatic tool to predict ICU admission. The authors recommend a combination of a beta-lactam/beta-lactamase inhibitor or a third G cephalosporin plus a macrolide in most SCAP patients, and to empirically cover PES (P. aeruginosa, extended spectrum beta-lactamase producing Enterobacteriaceae, methicillin-resistant S. aureus) pathogens when at least two specific risk factors are present. In patients with influenza CAP, the authors recommend the use of oseltamivir and avoidance of the use of steroids. Corticosteroids can be used in case of refractory shock and high systemic inflammatory response.

Biomarkers and clinical scoring systems in community-acquired pneumonia

Community-acquired pneumonia (CAP) is the third most common cause of death globally. Due to the complexity of CAP, it is widely accepted that, currently, clinical prognosis and diagnosis is inadequate for the assessment of the severity of the disease. With the aim to determining the initial treatment and the appropriate level of intervention, several clinical scores of severity and biomarkers have been developed. Both biomarkers and clinical scoring systems are expected to determine the different aspects of the host factor and the response to therapy, in order for physicians to be able to make an accurate benefit/risk assessment that will lead to proper diagnosis and correct prescription of antibiotics. This review aims to highlight the prognostic and diagnostic accuracy of various laboratory and clinical parameters in CAP and discuss the perspectives for the reduction of CAP mortality.