Blood biomarkers differentiating viral versus bacterial pneumonia aetiology: a literature review

Biomarkers associated with vaccine-associated enhanced respiratory disease following influenza A virus infection in swine

Influenza A virus (IAV) is a major pathogen in the swine industry. Whole-inactivated virus (WIV) vaccines in swine are highly effective against homologous viruses but provide limited protection to antigenically divergent viruses and may lead to vaccine-associated enhanced respiratory disease (VAERD) after heterologous infection. Although VAERD is reproducible in laboratory studies, clinical diagnosis is challenging, as it would require both knowledge of prior vaccine history and evidence of severe disease by assessment of pathologic lesions at necropsy following infection with a heterologous virus. The objective of this study was to identify potential biomarkers for VAERD for antemortem clinical diagnosis. Naïve pigs were split into two groups, and one group was vaccinated with IAV WIV vaccine. All pigs were then challenged with a heterologous virus to induce VAERD in the vaccinated group and necropsied at 5 days post infection (dpi). Blood was collected on 0, 1, 3, and 5 dpi, and assessed by hematology, plasma chemistry, acute phase proteins, and citrullinated H3 histone (CitH3) assays. Additionally, cytokine and CitH3 levels were assessed in bronchoalveolar lavage fluid (BALF) collected at necropsy. Compared to nonvaccinated challenged pigs, blood collected from vaccinated and challenged (V/C) pigs with VAERD had elevated white blood cells and neutrophils, elevated C-reactive protein and haptoglobin acute phase proteins, and elevated CitH3. In BALF, the proinflammatory cytokine IL-8 and CitH3 were elevated in V/C pigs. In conclusion, a profile of elevated white blood cells and neutrophils, elevated C-reactive protein and haptoglobin, and elevated CitH3 may be relevant for a clinical antemortem IAV VAERD diagnosis.

New Guidelines for Severe Community-acquired Pneumonia

In 2023, the new European guidelines on severe community-acquired pneumonia, providing clinical practice recommendations for the management of this life-threatening infection, characterized by a high burden of mortality, morbidity, and costs for the society. This review article aims to summarize the principal evidence related to eight different questions covered in the guidelines, by also highlighting the future perspectives for research activity.

Radiographic findings of adenoviral pneumonia in children

OBJECTIVE

Adenovirus pneumonia is a common cause of community-acquired pneumonia in children and can mimic bacterial pneumonia, but there are few publications on its radiographic features. This study has evaluated the chest radiography findings of community-acquired adenovirus pneumonia in children. The frequency of radiological findings mimicking bacterial pneumonia was investigated. The clinical features of patients with adenovirus pneumonia possessing radiological findings mimicking bacterial pneumonia were also evaluated.

MATERIALS AND METHODS

The chest radiographs of patients diagnosed with adenovirus pneumonia were retrospectively reviewed. The chest radiographs were interpreted independently by a pediatric infectious disease specialist and a pediatric radiologist. Chest radiography findings mimicking bacterial pneumonia (bacterial-like) were specified as consolidation +/- pleural effusion. Other findings on chest radiography or a completely normal chest X-ray were specified as findings that were compatible with "typical viral pneumonia".

RESULTS

A total of 1407 patients were positive for adenovirus with respiratory multiplex PCR. The 219 patients who met the study criteria were included in the study. Chest radiographs were normal in 58 (26.5 %) patients. The chest radiograph findings mimicked bacterial pneumonia in 41 (18.7 %) patients.

CONCLUSION

Adenovirus pneumonia occurs predominantly in children aged five years and younger, as with other viral pneumonias. The radiographic findings in adenovirus pneumonia are predominantly those seen in viral pneumonia. Increasing age and positivity for only adenovirus without other viruses on respiratory multiplex PCR were associated with the chest radiograph being more likely to be "bacterial-like". Adenovirus may lead to lobar/segmental consolidation at a rate that is not very rare.

Plasma levels of neurogenic inflammation related neuropeptides in pediatric patients with community-acquired pneumonia and their potential diagnostic value in distinguishing viral and bacterial pneumonia

Neurogenic inflammation is involved in the development and progression of respiratory inflammatory diseases. However, its role in community-acquired pneumonia (CAP) remains unclear. We therefore aimed to investigate plasma levels of neurogenic inflammation-related neuropeptides, calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY), and procalcitonin (PCT) in pediatric patients with CAP and to assess their diagnostic value in viral and bacterial/mixed pneumonia. A total of 124 pediatric patients with CAP (1 month-18 years old) and 56 healthy children of similar ages were prospectively enrolled. The patients were classified as viral (n = 99) and bacterial/mixed (n = 25) pneumonia. Plasma levels of the peptides were quantified by ELISA. ROC analysis was performed to evaluate possible diagnostic value of the peptides. While plasma levels of CGRP, VIP and PCT were significantly higher in patients with CAP than in the control group, respectively, NPY levels were significantly lower. Moreover, plasma levels of all neuropeptides and PCT were significantly higher in bacterial pneumonia patients compared to viral pneumonia patients. ROC analysis revealed that CGRP, SP and NPY had a diagnostic value in distinguishing viral and bacterial/mixed pneumonia.

CONCLUSIONS

Our findings suggest that these neuropeptides may be implicated in pediatric CAP. CGRP, SP and NPY together may be a promising candidate in distinguishing viral and bacterial/mixed pneumonia, however, for this, further studies are needed.

WHAT IS KNOWN

• Neurogenic inflammation contributes to the development and progression of respiratory inflammatory diseases such as chronic obstructive pulmonary disease and bronchial asthma.

WHAT IS NEW

• Plasma levels of neurogenic inflammation related neuropeptides calcitonin gene-related peptide, substance P, vasoactive intestinal peptide and neuropeptide Y are changed in pediatric community-acquired pneumonia. Calcitonin gene-related peptide, substance P and neuropeptide Y are promising candidates in distinguishing viral and bacterial/mixed pneumonia.

Fever in focus: Symptoms, diagnoses and treatment of febrile children in Ghana-A longitudinal hospital study

BACKGROUND

Healthcare resources are often limited in areas of sub-Saharan Africa. This makes accurate and timely diagnoses challenging and delays treatment of childhood febrile illness. We explored longitudinal characteristics related to symptoms, diagnosis and treatment of hospitalised febrile children in a rural area of Ghana highly endemic for malaria.

METHODS

Febrile children under 15 years, admitted to the study hospital paediatric ward, were recruited to the study and clinical data were collected throughout hospitalisation. Descriptive statistics were reported for all cases; for longitudinal analyses, a subset of visits with limited missing data was used.

RESULTS

There were 801 hospitalised children included in longitudinal analyses. Malaria (n = 581, 73%) and sepsis (n = 373, 47%) were the most prevalent suspected diagnoses on admission. One-third of malaria suspected diagnoses (n = 192, 33%) were changed on the discharge diagnosis, compared to 84% (n = 315) of sepsis suspected diagnoses. Among malaria-only discharge diagnoses, 98% (n/N = 202/207) received an antimalarial and 33% (n/N = 69/207) an antibiotic; among discharge diagnoses without malaria, 28% (n/N = 108/389) received an antimalarial and 83% (n/N = 324/389) an antibiotic.

CONCLUSIONS

Suspected diagnoses were largely based on clinical presentation and were frequently changed; changed diagnoses were associated with lingering symptoms, underscoring the need for faster and more accurate diagnostics. Medications were over-prescribed regardless of diagnosis stability, possibly because of a lack of confidence in suspected diagnoses. Thus, better diagnostic tools are needed for childhood febrile illnesses to enhance the accuracy of and confidence in diagnoses, and to cut down unjustified medication use, reducing the risk of antimicrobial and malaria resistance.

Dynamics of platelet parameters in children with severe community-acquired pneumonia between viral and bacterial infections

Background

Changes in platelet parameters may vary according to the different pathogens. However, little is known about the differences in platelet parameters in children with severe community-acquired pneumonia (CAP) children of viral and bacterial infections.

Methods

This was a single-center retrospective study that included 156 children with severe CAP. Dynamic changes in platelet parameters, including platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW) and plateletcrit (PCT), were recorded at 24 h, 48 h, 72 h, and day 7 of admission, as well as at discharge.

Results

At 72 h of admission, PLT in the viral infection group was significantly lower than that in the bacterial infection and bacterial and viral coinfections group. Meanwhile, the curve of changes in PLT (ΔPLT) in the viral infection group was clearly separated from the other two groups at this time point. Receiver operating characteristic (ROC) analysis showed that PLT at 72 h of admission could assist in distinguishing bacterial and viral infections in severe pneumonia children with the area under curve (AUC) value of 0.683 [95% confidence interval (CI): 0.561-0.805, P=0.007]. However, its sensitivity and specificity were not high, at 68% and 65%, respectively.

Conclusions

Although the diagnostic value of platelet parameters in bacterial and viral infection in children with severe CAP is limited, they are still expected to be combined with other indicators to provide a reference for timely treatment.

Epidemiological, Clinical, and Laboratory Findings of 235 Hospitalized COVID-19 Adult Patients (Survivors and Non-Survivors) at Sohar Hospital in Oman

OBJECTIVES

The aim of this study was to describe the epidemiological and clinical characteristics and laboratory findings of coronavirus disease 2019 (COVID-19) patients at the Sohar Hospital, Sohar, Oman.

METHODS

This retrospective study of admitted COVID-19 patients at Sohar Hospital in Oman was carried out from March to October 2020. Demographics and laboratory data of 19 tests for 235 COVID-19 patients, of which 202 were survivors and 33 were non-survivors, were collected from the hospital information system after ethics approval.

RESULTS

Thirteen factors were significantly correlated with in-hospital mortality, including older age, having chronic disease, high neutrophil count, high troponin T, high creatinine, low albumin (p < 0.0001), high white blood cell (WBC) count, low hemoglobin, high D-dimer (p < 0.001), high C-reactive protein (CRP) (p < 0.002), low lymphocyte count (p < 0.003), high alkaline phosphatase (ALP) enzyme (p < 0.007) and high ferritin (p < 0.045). The most common laboratory blood test abnormalities that were highly correlated with mortality were increased values of CRP (100% of non-survivors), D-dimer (94.1% of non-survivors), ferritin (88.2% of non-survivors), and troponin T (85% of non-survivors) and reduced lymphocyte count (73.9% of non-survivors).

CONCLUSION

These findings could help in categorizing COVID-19 patients for risk-based assessment and early identification of patients with poor prognosis.

Development and validation of a hybrid deep learning-machine learning approach for severity assessment of COVID-19 and other pneumonias

The Coronavirus Disease 2019 (COVID-19) is transitioning into the endemic phase. Nonetheless, it is crucial to remain mindful that pandemics related to infectious respiratory diseases (IRDs) can emerge unpredictably. Therefore, we aimed to develop and validate a severity assessment model for IRDs, including COVID-19, influenza, and novel influenza, using CT images on a multi-centre data set. Of the 805 COVID-19 patients collected from a single centre, 649 were used for training and 156 were used for internal validation (D1). Additionally, three external validation sets were obtained from 7 cohorts: 1138 patients with COVID-19 (D2), and 233 patients with influenza and novel influenza (D3). A hybrid model, referred to as Hybrid-DDM, was constructed by combining two deep learning models and a machine learning model. Across datasets D1, D2, and D3, the Hybrid-DDM exhibited significantly improved performance compared to the baseline model. The areas under the receiver operating curves (AUCs) were 0.830 versus 0.767 (p = 0.036) in D1, 0.801 versus 0.753 (p < 0.001) in D2, and 0.774 versus 0.668 (p < 0.001) in D3. This study indicates that the Hybrid-DDM model, trained using COVID-19 patient data, is effective and can also be applicable to patients with other types of viral pneumonia.

Immunologic biomarkers for bacterial meningitis

Meningitis is defined as the inflammation of the meninges that is most often caused by various bacterial and viral pathogens, and is associated with high rates of mortality and morbidity. Early detection of bacterial meningitis is essential to appropriate antibiotic therapy. Alterations in immunologic biomarkers levels have been considered the diagnostic approach in medical laboratories for the identifying of infections. The early increasing immunologic mediators such as cytokines and acute phase proteins (APPs) during bacterial meningitis have made they significant indicators for laboratory diagnosis. Immunology biomarkers showed wide variable sensitivity and specificity values that influenced by different reference values, selected a certain cutoff point, methods of detection, patient characterization and inclusion criteria, as well as etiology of meningitis and time of CSF or blood specimens' collection. This study provides an overview of different immunologic biomarkers as diagnostic markers for the identification of bacterial meningitis and their efficiencies in the differentiating of bacterial from viral meningitis.

Epidemiologic, clinical, and serum markers may improve discrimination between bacterial and viral etiologies of childhood pneumonia

Background

Discrimination of bacterial and viral etiologies of childhood community-acquired pneumonia (CAP) is often challenging. Unnecessary antibiotic administration exposes patients to undue risks and may engender antimicrobial resistance. This study aimed to develop a prediction model using epidemiological, clinical and laboratory data to differentiate between bacterial and viral CAP.

Methods

Data from 155 children with confirmed bacterial or mixed bacterial and viral infection (N = 124) and viral infection (N = 31) were derived from a comprehensive assessment of causative pathogens [Partnerships for Enhanced Engagement in Research-Pneumonia in Pediatrics (PEER-PePPeS)] conducted in Indonesia. Epidemiologic, clinical and biomarker profiles (hematology and inflammatory markers) were compared between groups. The area under the receiver operating characteristic curve (AUROC) for varying biomarker levels was used to characterize performance and determine cut-off values for discrimination of bacterial and mixed CAP versus viral CAP. Diagnostic predictors of bacterial and mixed CAP were assessed by multivariate logistic regression.

Results

Diarrhea was more frequently reported in bacterial and mixed CAP, while viral infections more frequently occurred during Indonesia's rainy season. White blood cell counts (WBC), absolute neutrophil counts (ANC), neutrophil-lymphocyte ratio (NLR), C-reactive protein (CRP), and procalcitonin (PCT) were significantly higher in bacterial and mixed cases. After adjusting for covariates, the following were the most important predictors of bacterial or mixed CAP: rainy season (aOR 0.26; 95% CI 0.08-0.90; p = 0.033), CRP ≥5.70 mg/L (aOR 4.71; 95% CI 1.18-18.74; p = 0.028), and presence of fever (aOR 5.26; 95% CI 1.07-25.91; p = 0.041). The model assessed had a low R-squared (Nagelkerke R² = 0.490) but good calibration (p = 0.610 for Hosmer Lemeshow test). The combination of CRP and fever had moderate predictive value with sensitivity and specificity of 62.28 and 65.52%, respectively.

Conclusion

Combining clinical and laboratory profiles is potentially valuable for discriminating bacterial and mixed from viral pediatric CAP and may guide antibiotic use. Further studies with a larger sample size should be performed to validate this model.

Validation of a Multi-Analyte Immunoassay for Distinguishing Bacterial vs. Viral Infections in a Pediatric Cohort

BACKGROUND

Clinical presentation of viral and bacterial infections or co-infections overlaps significantly. Pathogen identification is the gold standard for appropriate treatment. Recently, FDA cleared a multivariate index test called MeMed-BV that distinguishes viral and bacterial infections based on the differential expression of 3 host proteins. Here, we sought to validate MeMed-BV immunoassay on MedKey analyzer in our pediatric hospital following guidelines from the Clinical and Laboratory Standards Institute.

METHODS

The analytical performance of the MeMed-BV test was evaluated with precision (intra- and inter-assay), method comparison and interference studies. The clinical performance (diagnostic sensitivity and specificity) of the MeMed-BV test was assessed by conducting a retrospective cohort study (n=60) using plasma samples from pediatric patients with acute febrile illness who visited the emergency department of our hospital.

RESULTS

MeMed-BV showed acceptable intra- and inter-assay precision with a range of <3 score units in both the high-score bacterial as well as the low-score viral controls. Diagnostic accuracy studies revealed a sensitivity of 94% and specificity of 88% for identifying bacterial infections or co-infections. Our MeMed-BV results showed an excellent agreement (R=0.998) with manufacturer's laboratory data and compared well with ELISA studies. Gross hemolysis and icterus did not affect the assay, but gross lipemia showed a considerable bias in samples with moderate likelihood of viral infection. Importantly, the MeMed-BV test performed better than routinely measured infection-related biomarkers like white blood cell counts, procalcitonin and C-reactive protein in classifying bacterial infections.

CONCLUSION

MeMed-BV immunoassay demonstrated acceptable analytical performance and is reliable for distinguishing viral and bacterial infections or co-infections in pediatric patients. Future studies are warranted to examine the clinical utility, especially with respect to reducing the need for blood cultures and time to treatment for the patient.

Shine: A novel strategy to extract specific, sensitive and well-conserved biomarkers from massive microbial genomic datasets

BACKGROUND

Concentrations of the pathogenic microorganisms' DNA in biological samples are typically low. Therefore, DNA diagnostics of common infections are costly, rarely accurate, and challenging. Limited by failing to cover updated epidemic testing samples, computational services are difficult to implement in clinical applications without complex customized settings. Furthermore, the combined biomarkers used to maintain high conservation may not be cost effective and could cause several experimental errors in many clinical settings. Given the limitations of recent developed technology, 16S rRNA is too conserved to distinguish closely related species, and mosaic plasmids are not effective as well because of their uneven distribution across prokaryotic taxa.

RESULTS

Here, we provide a computational strategy, Shine, that allows extraction of specific, sensitive and well-conserved biomarkers from massive microbial genomic datasets. Distinguished with simple concatenations with blast-based filtering, our method involves a de novo genome alignment-based pipeline to explore the original and specific repetitive biomarkers in the defined population. It can cover all members to detect newly discovered multicopy conserved species-specific or even subspecies-specific target probes and primer sets. The method has been successfully applied to a number of clinical projects and has the overwhelming advantages of automated detection of all pathogenic microorganisms without the limitations of genome annotation and incompletely assembled motifs. Using on our pipeline, users may select different configuration parameters depending on the purpose of the project for routine clinical detection practices on the website https://bioinfo.liferiver.com.cn with easy registration.

CONCLUSIONS

The proposed strategy is suitable for identifying shared phylogenetic markers while featuring low rates of false positive or false negative. This technology is suitable for the automatic design of minimal and efficient PCR primers and other types of detection probes.

Modern approaches at the management of children with community-acquired pneumonia

Experts of The Union of Pediatricians of Russia have developed current clinical guidelines for management of children with community-acquired pneumonia, which were approved by the Scientific and Practice Council of Ministry of Public Health of the Russian Federation in January 2022. Particular attention is paid to the etiological structure, modern classification, diagnostic tests and flagship approaches to antibacterial therapy of community-acquired pneumonia in children based on the principles of evidentiary medicine. 

Metabolomics in pediatric lower respiratory tract infections and sepsis: a literature review

Lower respiratory tract infections (LRTIs) are a leading cause of morbidity and mortality in children. The ability of healthcare providers to diagnose and prognose LRTIs in the pediatric population remains a challenge, as children can present with similar clinical features regardless of the underlying pathogen or ultimate severity. Metabolomics, the large-scale analysis of metabolites and metabolic pathways offers new tools and insights that may aid in diagnosing and predicting the outcomes of LRTIs in children. This review highlights the latest literature on the clinical utility of metabolomics in providing care for children with bronchiolitis, pneumonia, COVID-19, and sepsis. IMPACT: This article summarizes current metabolomics approaches to diagnosing and predicting the course of pediatric lower respiratory infections. This article highlights the limitations to current metabolomics research and highlights future directions for the field.

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.

Application of Biomarkers in the Diagnostic Distinction of Bacterial and Viral Infections

Infectious diseases, which pose a great threat worldwide, have a significant impact on public health and the world economy. It contributes to increased healthcare costs, unnecessary drug-related side effects, and increased antimicrobial resistance. It is not always easy to distinguish the etiological differentiation of diseases that can develop with bacteria and viruses. Therefore, one of the biggest challenges in medicine is how to correctly distinguish between the different causes of these infections and how to manage the patient. Because bacterial and viral infections often present similar symptoms. The real decision is whether the infection is caused by bacteria or viruses and whether to treat the patient with antibiotics. There are many different methodological approaches to diagnosing infections. Biomarkers have been used in the diagnosis of diseases and other conditions for many years. Biomarkers are molecules found in blood and body fluids in measurable amounts, which can evaluate biological and pathological processes. These key indicators can provide vital information in determining disease prognosis, predicting response to treatments, adverse events and drug interactions, and identifying key risks. An effective biomarker is extremely important for the early diagnosis of various diseases. The explosion of interest in biomarker research is driving the development of new predictive, diagnostic, and prognostic products in modern medical practice. The purpose of this review is to demonstrate the use and diagnostic potential of current and investigational biomarkers in the distinction between bacterial and viral infections.

Epidemiology of community-acquired pneumonia among hospitalised children in Indonesia: a multicentre, prospective study

OBJECTIVE

To identify aetiologies of childhood community-acquired pneumonia (CAP) based on a comprehensive diagnostic approach.

DESIGN

'Partnerships for Enhanced Engagement in Research-Pneumonia in Paediatrics (PEER-PePPeS)' study was an observational prospective cohort study conducted from July 2017 to September 2019.

SETTING

Government referral teaching hospitals and satellite sites in three cities in Indonesia: Semarang, Yogyakarta and Tangerang.

PARTICIPANTS

Hospitalised children aged 2-59 months who met the criteria for pneumonia were eligible. Children were excluded if they had been hospitalised for >24 hours; had malignancy or history of malignancy; a history of long-term (>2 months) steroid therapy, or conditions that might interfere with compliance with study procedures.

MAIN OUTCOMES MEASURES

Causative bacterial, viral or mixed pathogen(s) for pneumonia were determined using microbiological, molecular and serological tests from routinely collected specimens (blood, sputum and nasopharyngeal swabs). We applied a previously published algorithm (PEER-PePPeS rules) to determine the causative pathogen(s).

RESULTS

188 subjects were enrolled. Based on our algorithm, 48 (25.5%) had a bacterial infection, 31 (16.5%) had a viral infection, 76 (40.4%) had mixed bacterial and viral infections, and 33 (17.6%) were unable to be classified. The five most common causative pathogens identified were Haemophilus influenzae non-type B (N=73, 38.8%), respiratory syncytial virus (RSV) (N=51, 27.1%), Klebsiella pneumoniae (N=43, 22.9%), Streptococcus pneumoniae (N=29, 15.4%) and Influenza virus (N=25, 13.3%). RSV and influenza virus diagnoses were highly associated with Indonesia's rainy season (November-March). The PCR assays on induced sputum (IS) specimens captured most of the pathogens identified in this study.

CONCLUSIONS

Our study found that H. influenzae non-type B and RSV were the most frequently identified pathogens causing hospitalised CAP among Indonesian children aged 2-59 months old. Our study also highlights the importance of PCR for diagnosis and by extension, appropriate use of antimicrobials.

TRAIL REGISTRATION NUMBER

NCT03366454.

Childhood Pneumonia Diagnostics in Sub-Saharan Africa: A Systematic Review

BACKGROUND

The prompt and accurate aetiological diagnosis of childhood pneumonia remains a challenge, especially in sub-Saharan Africa (SSA) because of limited resources for disease management.

OBJECTIVE

To review existing diagnostics for childhood pneumonia and potential modalities available to differentiate between bacterial and viral aetiologies in SSA.

METHODS

Online databases were searched for relevant articles published between January 2010 and December 2020 regarding childhood pneumonia diagnosis, conducted in SSA in children less than 18 years of age. The 2020 PRISMA checklist was utilized in appraising the selected studies and the QUADAS-2 tool was employed to assess the risk of bias in each of the studies selected.

RESULTS

A total of 1542 study titles and abstracts were screened following which 45 studies (39 on childhood pneumonia diagnostics and 6 on discriminating between bacterial and viral childhood pneumonia) were selected for review. Microbiological investigations (79.7%) constituted the most utilized index tests with blood-related specimen (32.8%) being the most utilized specimen. The most performed index diagnostic modality was polymerase chain reaction (PCR) (53.1%). The commonest reference gold standard technique was based on clinical diagnosis of the disease (46.2%). Only six studies in SSA attempted at using serum biomarkers, either singly or in combination to distinguish between aetiologies with use of combined biomarkers showing promise.

CONCLUSION

Microbiological investigations are the most employed diagnostic methods for childhood pneumonia in SSA. More studies are required to evaluate the potential use of serum biomarkers; either singly or in combination with the goal of discriminating bacterial and viral childhood pneumonia.

Fibronectin as a Marker of Disease Severity in Critically Ill COVID-19 Patients

The SARS-CoV-2 virus alters the expression of genes for extracellular matrix proteins, including fibronectin. The aim of the study was to establish the relationship between different forms of fibronectin, such as plasma (pFN), cellular (EDA-FN), and proteolytic FN-fragments, and disease severity and mortality of critically ill patients treated in the intensive care unit. The levels of pFN, EDA-FN, and FN-fragments were measured in patients with a viral (N = 43, COVID-19) or bacterial (N = 41, sepsis) infection, using immunoblotting and ELISA. The level of EDA-FN, but not pFN, was related to the treatment outcome and was significantly higher in COVID-19 Non-survivors than in Survivors. Furthermore, EDA-FN levels correlated with APACHE II and SOFA scores. FN-fragments were detected in 95% of COVID-19 samples and the amount was significantly higher in Non-survivors than in Survivors. Interestingly, FN-fragments were present in only 56% of samples from patients with bacterial sepsis, with no significant differences between Non-survivors and Survivors. The new knowledge gained from our research will help to understand the differences in immune response depending on the etiology of the infection. Fibronectin is a potential biomarker that can be used in clinical settings to monitor the condition of COVID-19 patients and predict treatment outcomes.

Comparison of a Point-of-Care FilmArray Test to Standard-of-Care Microbiology Test in Diagnosis of Healthcare Associated Infections in a Tertiary Care Pediatric Intensive Care Unit

Background: Rapid and accurate identification of healthcare associated pathogens is crucial for early diagnosis and treatment of infections. This study aimed to assess the performance of a point-of-care multiplex polymerase chain reaction (PCR) in diagnosis of pathogens and their antibiotic resistance genes in bloodstream infections, pneumonia and meningitis/encephalitis in a pediatric intensive care unit (PICU). Methods: A retrospective cross-sectional study was conducted on pediatric patients diagnosed with healthcare associated infections at Alexandria University PICU, Egypt. A total of 111 samples from 98 patients were subjected simultaneously to standard-of-care microbiology testing (SOCMT) and molecular testing by BioFire multiplex PCR. Results: In comparison to SOCMT, the BioFire FilmArray^® had a better diagnostic yield with broncho-alveolar lavage (BAL) (45 vs. 21) and cerebrospinal fluid (CSF) samples (five vs. none) (p ≤ 0.0001). Klebsiella pneumoniae was the most common pathogen in BAL (n = 19 by BioFire, n = 9 by SOCMT) and blood (n = 7, by SOCMT and BioFire) samples, while Streptococcus pneumoniae was the most common in CSF samples. BioFire showed 95.8% overall percent agreement, 100% positive percent agreement and 95.6% negative percent agreement with SOCMT. All phenotypically confirmed resistant isolates had resistance genes by the BioFire FilmArray^® (100%). The turnaround time (TAT) of positive results by the FilmArray panels was 1–1.5 h in comparison to 48–72 h by SOCMT (p ≤ 0.001). Conclusions: The results of the current study confirm the utility of the BioFire FilmArray^® in making early decisions regarding patients’ diagnosis and management of infection in the PICU, in terms of rapid TAT and appropriate antimicrobial use.

Association of Clinical Signs, Host Biomarkers and Etiology With Radiological Pneumonia in Bhutanese Children

Diagnosing pneumonia and identifying those requiring antibiotherapy remain challenging. Chest radiographs (CXR) are often used as the reference standard. We aimed to describe clinical characteristics, host-response biomarkers and etiology, and assess their relationship to CXR findings in children with pneumonia in Thimphu, Bhutan. Children between 2 and 59 months hospitalized with WHO-defined pneumonia were prospectively enrolled and classified into radiological endpoint and non-endpoint pneumonia. Blood and nasopharyngeal washing were collected for microbiological analyses and plasma levels of 11 host-response biomarkers were measured. Among 149 children with readable CXR, 39 (26.2%) presented with endpoint pneumonia. Identification of respiratory viruses was common, with no significant differences by radiological outcomes. No clinical sign was suggestive of radiological pneumonia, but children with radiological pneumonia presented higher erythrocyte sedimentation rate, C-reactive protein and procalcitonin. Markers of endothelial and immune activation had little accuracy for the reliable identification of radiological pneumonia.

Severe Infections Due to Respiratory Viruses

Severe viral infections may result in severe illnesses capable of causing acute respiratory failure that could progress rapidly to acute respiratory distress syndrome (ARDS), related to worse outcomes, especially in individuals with a higher risk of infection, including the elderly and those with comorbidities such as asthma, diabetes mellitus and chronic respiratory or cardiovascular disease. In addition, in cases of severe viral pneumonia, co-infection with bacteria such as Streptococcus pneumoniae and Staphylococcus aureus is related to worse outcomes. Respiratory viruses like influenza, rhinovirus, parainfluenza, adenovirus, metapneumovirus, respiratory syncytial virus, and coronavirus have increasingly been detected. This trend has become more prevalent, especially in critically ill patients, due to the availability and implementation of molecular assays in clinical practice. Respiratory viruses have been diagnosed as a frequent cause of severe pneumonia, including cases of community-acquired pneumonia, hospital-acquired pneumonia, and ventilator-associated pneumonia. In this review, we will discuss the epidemiology, diagnosis, clinical characteristics, management, and prognosis of patients with severe infections due to respiratory viruses, with a focus on influenza viruses, non-influenza viruses, and coronaviruses.

Developments in pediatrics in 2020: choices in allergy, autoinflammatory disorders, critical care, endocrinology, genetics, infectious diseases, microbiota, neonatology, neurology, nutrition, ortopedics, respiratory tract illnesses and rheumatology

In this article, we describe the advances in the field of pediatrics that have been published in the Italian Journal of Pediatrics in 2020. We report progresses in understanding allergy, autoinflammatory disorders, critical care, endocrinology, genetics, infectious diseases, microbiota, neonatology, neurology, nutrition, orthopedics, respiratory tract illnesses, rheumatology in childhood.

Systematic Study on a Quantitative Analysis of Multicomponents by Single Marker (QAMS) Method for Simultaneous Determination of Eight Constituents in Pneumonia Mixture by UPLC-MS/MS

Pneumonia mixture was formulated and is available to treat children acute pneumonia and acute bronchitis in our hospital for nearly forty years, but there are few studies of its quality evaluation or control. In this paper, a new strategy for quality evaluation of pneumonia mixture was explored and verified through qualitative and quantitative analyses of multicomponents by single marker (QAMS) by UPLC-MS/MS. Baicalein was selected as an internal reference, and the relative correction factors (RCFs) and the relative retention time (RRT) of (R, S)-goitrin, amygdalin, chlorogenic acid, pseudoephedrine hydrochloride, ephedrine hydrochloride, ammonium glycyrrhizinate, and baicalin were established. The robustness and durability of the QAMS method were investigated. RCF values calculated by the average (AVG) method and linear regression (LRG) method had good repeatability and were acceptable for quantitative analysis, and the RTT combined with the exact masses of precursor and fragment ions and their abundance could be adopted for accurately positioning the chromatographic peak of the eight constituents. The consistency and feasibility of the QAMS method were verified by comparing the contents of the seven components calculated by a classic and validated external standard method (ESM) with those of the QAMS method, which reduces analytical cost and time of detection and avoids the problem of the diversity and large quantity of reference standards. The results demonstrated that the QAMS method developed in this paper could provide a new, alternative, and promising method to comprehensively and effectively determine multicomponents and control the quality of pneumonia mixture or even a group of similar medicines.

Systematic Review and Meta-Analysis of Diagnostic Biomarkers for Pediatric Pneumonia

BACKGROUND

Pneumonia causes significant morbidity and mortality in children worldwide, especially in resource-poor settings. Accurate identification of bacterial etiology leads to timely antibiotic initiation, minimizing overuse, and development of resistance. Host biomarkers may improve diagnostic sensitivity and specificity. We assessed the ability of biomarkers to correctly identify bacterial pneumonia in children who present with respiratory distress.

METHODS

A librarian-directed search was conducted of MEDLINE, EMBASE, CENTRAL, Global Health, the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov to May 2020 with no language restriction. Included studies compared a diagnostic biomarker in children with bacterial pneumonia to those with nonbacterial respiratory distress.

RESULTS

There were 31 observational studies of 23 different biomarkers. C-reactive protein (CRP), procalcitonin (PCT), white blood cell (WBC) count, and erythrocyte sedimentation rate (ESR) were the biomarkers with sufficient data for meta-analysis. Meta-analysis revealed that CRP and PCT best differentiated bacterial from viral pneumonia with CRP summary AUROC (area under the receiver operating characteristic curve) 0.71 (0.69-0.73), Youden index 53 mg/L, sensitivity 0.70 (0.68-0.78), and specificity 0.64 (0.58-0.68) and PCT summary AUROC 0.70 (0.67-0.74), Youden index 0.59 ng/mL, sensitivity 0.69 (0.65-0.77), and specificity 0.64 (0.60-0.68). WBC and ESR did not perform as well. Nineteen other inflammatory and immunologic biomarkers were identified including CRP/mean platelet value, neutrophil/leukocyte ratio, interleukin 6, and interferon-alpha, with sensitivities from 60% to 85% and specificities from 76% to 83%.

CONCLUSION

CRP and PCT performed better than WBC and ESR but had suboptimal sensitivity. Some less well-studied novel biomarkers appear to have promise particularly in combination.

Challenges of Antibiotic Stewardship in the Pediatric and Neonatal Intensive Care Units

The goals of antimicrobial stewardship programs (ASPs) are to optimize antimicrobial prescribing habits in order to improve patient outcomes, reduce antimicrobial resistance, and reduce hospital costs. Multiple society-endorsed guidelines and government policies reinforce the importance of ASP implementation. Effective antimicrobial stewardship can impact unique patients, hospitals, and societal antibiotic-resistance burden. The role and subsequent success of these programs has largely been reported in the adult population. Pediatric and neonatal intensive care units present unique challenges for traditional antimicrobial stewardship approaches. The purpose of this review article is to explore the challenges of appropriate antibiotic use in the pediatric and neonatal intensive care units and to summarize strategies ASPs can use to overcome these challenges. These problems include non-specific disease presentations, limited evidence for definitive treatment durations in many pediatric infections, fewer pediatric-trained infectious disease physicians, and applicability of intensive laboratory obtainment, collection, and interpretation. Additionally, many ASP implementation studies evaluating the efficacy of ASPs exclude the PICU and NICU. Areas of focus for pediatric ASPs should likely include appropriate antibiotic initiation, appropriate antibiotic duration, and appropriate antibiotic de-escalation.

C-reactive protein or procalcitonin combined with rhinorrhea for discrimination of viral from bacterial infections in hospitalized adults in non-intensive care units with lower respiratory tract infections

BACKGROUND

Whether procalcitonin (PCT) or C-reactive protein (CRP) combined with certain clinical characteristics can better distinguish viral from bacterial infections remains unclear. The aim of the study was to assess the ability of PCT or CRP combined with clinical characteristics to distinguish between viral and bacterial infections in hospitalized non-intensive care unit (ICU) adults with lower respiratory tract infection (LRTI).

METHODS

This was a post-hoc analysis of a randomized clinical trial previously conducted among LRTI patients. The ability of PCT, CRP and PCT or CRP combined with clinical symptoms to discriminate between viral and bacterial infection were assessed by portraying receiver operating characteristic (ROC) curves among patients with only a viral or a typical bacterial infection.

RESULTS

In total, 209 infected patients (viral 69%, bacterial 31%) were included in the study. When using CRP or PCT to discriminate between viral and bacterial LRTI, the optimal cut-off points were 22 mg/L and 0.18 ng/mL, respectively. When the optimal cut-off for CRP (≤ 22 mg/L) or PCT (≤ 0.18 ng/mL) combined with rhinorrhea was used to discriminate viral from bacterial LRTI, the AUCs were 0.81 (95% CI: 0.75-0.87) and 0.80 (95% CI: 0.74-0.86), which was statistically significantly better than when CRP or PCT used alone (p < 0.001). When CRP ≤ 22 mg/L, PCT ≤ 0.18 ng/mL and rhinorrhea were combined, the AUC was 0.86 (95% CI: 0.80-0.91), which was statistically significantly higher than when CRP (≤ 22 mg/L) or PCT (≤ 0.18 ng/mL) was combined with rhinorrhea (p = 0.011 and p = 0.021).

CONCLUSIONS

Either CRP ≤ 22 mg/L or PCT ≤ 0.18 ng/mL combined with rhinorrhea could help distinguish viral from bacterial infections in hospitalized non-ICU adults with LRTI. When rhinorrhea was combined together, discrimination ability was further improved.

Asthma and COVID-19: Emphasis on Adequate Asthma Control

Asthmatics are at an increased risk of developing exacerbations after being infected by respiratory viruses such as influenza virus, parainfluenza virus, and human and severe acute respiratory syndrome coronaviruses (SARS-CoV). Asthma, especially when poorly controlled, is an independent risk factor for developing pneumonia. A subset of asthmatics can have significant defects in their innate, humoral, and cell-mediated immunity arms, which may explain the increased susceptibility to infections. Adequate asthma control is associated with a significant decrease in episodes of exacerbation. Because of their wide availability and potency to promote adequate asthma control, glucocorticoids, especially inhaled ones, are the cornerstone of asthma management. The current COVID-19 pandemic affects millions of people worldwide and possesses mortality several times that of seasonal influenza; therefore, it is necessary to revisit this subject. The pathogenesis of SARS-CoV-2, the virus that causes COVID-19, can potentiate the development of acute asthmatic exacerbation with the potential to worsen the state of chronic airway inflammation. The relationship is evident from several studies that show asthmatics experiencing a more adverse clinical course of SARS-CoV-2 infection than nonasthmatics. Recent studies show that dexamethasone, a potent glucocorticoid, and other inhaled corticosteroids significantly reduce morbidity and mortality among hospitalized COVID-19 patients. Hence, while we are waiting for more studies with higher level of evidence that further narrate the association between COVID-19 and asthma, we advise clinicians to try to achieve adequate disease control in asthmatics as it may reduce incidences and severity of exacerbations especially from SARS-CoV-2 infection.

Immunometabolic signatures predict risk of progression to sepsis in COVID-19

Viral sepsis has been proposed as an accurate term to describe all multisystemic dysregulations and clinical findings in severe and critically ill COVID-19 patients. The adoption of this term may help the implementation of more accurate strategies of early diagnosis, prognosis, and in-hospital treatment. We accurately quantified 110 metabolites using targeted metabolomics, and 13 cytokines/chemokines in plasma samples of 121 COVID-19 patients with different levels of severity, and 37 non-COVID-19 individuals. Analyses revealed an integrated host-dependent dysregulation of inflammatory cytokines, neutrophil activation chemokines, glycolysis, mitochondrial metabolism, amino acid metabolism, polyamine synthesis, and lipid metabolism typical of sepsis processes distinctive of a mild disease. Dysregulated metabolites and cytokines/chemokines showed differential correlation patterns in mild and critically ill patients, indicating a crosstalk between metabolism and hyperinflammation. Using multivariate analysis, powerful models for diagnosis and prognosis of COVID-19 induced sepsis were generated, as well as for mortality prediction among septic patients. A metabolite panel made of kynurenine/tryptophan ratio, IL-6, LysoPC a C18:2, and phenylalanine discriminated non-COVID-19 from sepsis patients with an area under the curve (AUC (95%CI)) of 0.991 (0.986-0.995), with sensitivity of 0.978 (0.963-0.992) and specificity of 0.920 (0.890-0.949). The panel that included C10:2, IL-6, NLR, and C5 discriminated mild patients from sepsis patients with an AUC (95%CI) of 0.965 (0.952-0.977), with sensitivity of 0.993(0.984-1.000) and specificity of 0.851 (0.815-0.887). The panel with citric acid, LysoPC a C28:1, neutrophil-lymphocyte ratio (NLR) and kynurenine/tryptophan ratio discriminated severe patients from sepsis patients with an AUC (95%CI) of 0.829 (0.800-0.858), with sensitivity of 0.738 (0.695-0.781) and specificity of 0.781 (0.735-0.827). Septic patients who survived were different from those that did not survive with a model consisting of hippuric acid, along with the presence of Type II diabetes, with an AUC (95%CI) of 0.831 (0.788-0.874), with sensitivity of 0.765 (0.697-0.832) and specificity of 0.817 (0.770-0.865).

Utility of the FebriDx point-of-care assay in supporting a triage algorithm for medical admissions with possible COVID-19: an observational cohort study

OBJECTIVE

To evaluate a triage algorithm used to identify and isolate patients with suspected COVID-19 among medical patients needing admission to hospital using simple clinical criteria and the FebriDx assay.

DESIGN

Retrospective observational cohort.

SETTING

Large acute National Health Service hospital in London, UK.

PARTICIPANTS

All medical admissions from the emergency department between 10 August 2020 and 4 November 2020 with a valid SARS-CoV-2 RT-PCR result.

INTERVENTIONS

Medical admissions were triaged as likely, possible or unlikely COVID-19 based on clinical criteria. Patients triaged as possible COVID-19 underwent FebriDx lateral flow assay on capillary blood, and those positive for myxovirus resistance protein A (a host response protein) were managed as likely COVID-19.

PRIMARY OUTCOME MEASURES

Diagnostic accuracy (sensitivity, specificity and predictive values) of the algorithm and the FebriDx assay using SARS-CoV-2 RT-PCR from nasopharyngeal swabs as the reference standard.

RESULTS

4.0% (136) of 3443 medical admissions had RT-PCR confirmed COVID-19. Prevalence of COVID-19 was 46% (80/175) in those triaged as likely, 4.1% (50/1225) in possible and 0.3% (6/2033) in unlikely COVID-19. Using a SARS-CoV-2 RT-PCR reference standard, clinical triage had sensitivity of 96% (95% CI 91% to 98%) and specificity of 61.5% (95% CI 59.8% to 63.1%), while the triage algorithm including FebriDx had sensitivity of 93% (95% CI 87% to 96%) and specificity of 86.4% (95% CI 85.2% to 87.5%). While 2033 patients were deemed not to require isolation using clinical criteria alone, the addition of FebriDx to clinical triage allowed a further 826 patients to be released from isolation, reducing the need for isolation rooms by 9.5 per day, 95% CI 8.9 to 10.2. Ten patients missed by the algorithm had mild or asymptomatic COVID-19.

CONCLUSIONS

A triage algorithm including the FebriDx assay had good sensitivity and was useful to 'rule-out' COVID-19 among medical admissions to hospital.

Salivary C-reactive protein-a possible predictor of serum levels in pediatric acute respiratory illness

Identifying the etiology of an acute respiratory infection in children is a well-known challenge. In this study, we evaluated the correlation between salivary C-reactive protein (CRP) and its serum counterpart, which is known to be higher in bacterial infections but necessitates a venipuncture. Salivary and serum CRPs were measured in children with an acute respiratory illness, aged 2 months to 18 years. Pearson's correlation coefficients were used to measure correlation. Discrimination of the salivary CRP levels for predicting serum levels above 100 mg/L was calculated and compared to serum CRP levels. Sensitivity and specificity were similarly calculated. Salivary CRP was measured in 104 samples. Levels correlated significantly and positively with serum CRP levels (r = 0.670, p<0.001). Area under the curve for predicting serum CRP levels of 100 mg/L was 0.848. For a salivary CRP concentration above 32,610 ng/L, the sensitivity and specificity were 69% and 93%, respectively, for accurately predicting a serum CRP level ≥100 mg/L.Conclusions: Salivary CRP can be used in the pediatric acute setting due to its high specificity for predicting elevated serum levels without the need for venipuncture. Further studies are required to achieve higher sensitivity rates. What is known: • Salivary C-reactive protein has shown correlation to its serum counterpart, mainly in healthy children, adults, and ill neonates. What is new: • In a large population of children with acute respiratory illness, aged 2 months to 18 years, salivary C-reactive protein showed high specificity for predicting elevated serum levels, thus indicating its potential as a diagnostic tool.

Novel point-of-care biomarker combination tests to differentiate acute bacterial from viral respiratory tract infections to guide antibiotic prescribing: a systematic review

BACKGROUND

Acute respiratory tract infections (RTIs) are the most common reason to seek medical care, with many patients receiving inappropriate antibiotics. Novel testing approaches to identify aetiology at the point-of-care are required to accurately guide antibiotic treatment.

OBJECTIVE

To assess the diagnostic accuracy of biomarker combinations to rapidly differentiate between acute bacterial or viral RTI aetiology.

DATA SOURCES

MEDLINE, Embase and Web of Science databases were searched to February 2021.

STUDY ELIGIBILITY CRITERIA

Diagnostic accuracy studies comparing accuracy of point-of-care and rapid diagnostic tests in primary or secondary care, consisting of biomarker combinations, to identify bacterial or viral aetiology of RTI.

METHODS

Risk of bias was assessed using the QUADAS-2 tool. Sensitivity and specificity of tests reported by more than one study were meta-analysed using a random effects model.

RESULTS

Twenty observational studies (3514 patients) were identified. Eighteen were judged at high risk of bias. For bacterial aetiologies, sensitivity ranged from 61% to 100% and specificity from 18% to 96%. For viral aetiologies, sensitivity ranged from 59% to 97% and specificity from 74% to 100%. Studies evaluating two commercial tests were meta-analysed. For ImmunoXpert, the summary sensitivity and specificity were 85% (95% CI 75%-91%, k = 4) and 86% (95% CI 73%-93%, k = 4) for bacterial infections, and 90% (95% CI 79%-96%, k = 3) and 92% (95% CI 83%-96%, k = 3) for viral infections, respectively. FebriDx had pooled sensitivity and specificity of 84% (95% CI 75%-90%, k = 4) and 93% (95% CI 90%-95%, k = 4) for bacterial infections, and 87% (95% CI 72%-95%; k = 4) and 82% (95% CI 66%-86%, k = 4) for viral infections, respectively.

CONCLUSION

Combinations of biomarkers show potential clinical utility in discriminating the aetiology of RTIs. However, the limitations in the evidence base, due to a high proportion of studies with high risk of bias, preclude firm conclusions. Future research should be in primary care and evaluate patient outcomes and cost-effectiveness with experimental study designs.

CLINICAL TRIAL

PROSPERO registration number: CRD42020178973.

Diagnostic Utility of a Ferritin-to-Procalcitonin Ratio to Differentiate Patients With COVID-19 From Those With Bacterial Pneumonia: A Multicenter Study

Background

There is an urgent need for accurate, rapid, inexpensive biomarkers that can differentiate coronavirus disease 2019 (COVID-19) from bacterial pneumonia. We assess the role of the ferritin-to-procalcitonin (F/P) ratio to classify pneumonia cases into those due to COVID-19 vs those due to bacterial pathogens.

Methods

This multicenter case–control study compared patients with COVID-19 with those with bacterial pneumonia, admitted between March 1 and May 31, 2020. Patients with COVID-19 and bacterial pneumonia co-infection were excluded. The F/P in patients with COVID-19 vs with bacterial pneumonia were compared. Receiver operating characteristic curve analysis determined the sensitivity and specificity of various cutoff F/P values for COVID-19 vs bacterial pneumonia.

Results

A total of 242 COVID-19 pneumonia cases and 34 bacterial pneumonia controls were included. Patients with COVID-19 pneumonia had a lower mean age (57.1 vs 64.4 years; P = .02) and a higher body mass index (30.74 vs 27.15 kg/m²; P = .02) compared with patients with bacterial pneumonia. Cases and controls had a similar proportion of women (47% vs 53%; P = .5), and COVID-19 patients had a higher prevalence of diabetes mellitus (32.6% vs 12%; P = .01). The median F/P was significantly higher in patients with COVID-19 (4037.5) compared with the F/P in bacterial pneumonia (802; P < .001). An F/P ≥877, used to diagnose COVID-19, resulted in a sensitivity of 85% and a specificity of 56%, with a positive predictive value of 93.2% and a likelihood ratio of 1.92. In multivariable analyses, an F/P ≥877 was associated with greater odds of identifying a COVID-19 case (odds ratio, 11.27; 95% CI, 4–31.2; P < .001).

Conclusions

An F/P ≥877 increases the likelihood of COVID-19 pneumonia compared with bacterial pneumonia.

Which Current and Novel Diagnostic Avenues for Bacterial Respiratory Diseases?

Bacterial acute pneumonia is responsible for an extremely large burden of death worldwide and diagnosis is paramount in the management of patients. While multidrug-resistant bacteria is one of the biggest health threats in the coming decades, clinicians urgently need access to novel diagnostic technologies. In this review, we will first present the already existing and largely used techniques that allow identifying pathogen-associated pneumonia. Then, we will discuss the latest and most promising technological advances that are based on connected technologies (artificial intelligence-based and Omics-based) or rapid tests, to improve the management of lung infections caused by pathogenic bacteria. We also aim to highlight the mutual benefits of fundamental and clinical studies for a better understanding of lung infections and their more efficient diagnostic management.

Diagnostic utility of a Ferritin-to-Procalcitonin Ratio to differentiate patients with COVID-19 from those with Bacterial Pneumonia: A multicenter study

IMPORTANCE

There is a need to develop tools to differentiate COVID-19 from bacterial pneumonia at the time of clinical presentation before diagnostic testing is available.

OBJECTIVE

To determine if the Ferritin-to-Procalcitonin ratio (F/P) can be used to differentiate COVID-19 from bacterial pneumonia.

DESIGN

This case-control study compared patients with either COVID-19 or bacterial pneumonia, admitted between March 1 and May 31, 2020. Patients with COVID-19 and bacterial pneumonia co-infection were excluded.

SETTING

A multicenter study conducted at three hospitals that included UCHealth and Phoebe Putney Memorial Hospital in the United States, and Yichang Central People's Hospital in China.

PARTICIPANTS

A total of 242 cases with COVID-19 infection and 34 controls with bacterial pneumonia.

MAIN OUTCOMES AND MEASURES

The F/P in patients with COVID-19 or with bacterial pneumonia were compared. Receiver operating characteristic analysis determined the sensitivity and specificity of various cut-off F/P values for the diagnosis of COVID-19 versus bacterial pneumonia.

RESULTS

Patients with COVID-19 pneumonia had a lower mean age (57.11 vs 64.4 years, p=0.02) and a higher BMI (30.74 vs 27.15 kg/m 2 , p=0.02) compared to patients with bacterial pneumonia. Cases and controls had a similar proportion of women (47% vs 53%, p=0.5) and COVID-19 patients had a higher prevalence of diabetes mellitus (32.6% vs 12%, p=0.01). The median F/P was significantly higher in patients with COVID-19 (4037.5) compared to the F/P in bacterial pneumonia (802, p<0.001). An F/P ≥ 877 used to diagnose COVID-19 resulted in a sensitivity of 85% and a specificity of 56%, with a positive predictive value of 93.2%, and a likelihood ratio of 1.92. In multivariable analyses, an F/P ≥ 877 was associated with greater odds of identifying a COVID-19 case (OR: 11.27, CI: 4-31.2, p<0.001).

CONCLUSIONS AND RELEVANCE

An F/P ≥ 877 increases the likelihood of COVID-19 pneumonia compared to bacterial pneumonia. Further research is needed to determine if obtaining ferritin and procalcitonin simultaneously at the time of clinical presentation has improved diagnostic value. Additional questions include whether an increased F/P and/or serial F/P associates with COVID-19 disease severity or outcomes.

Microbiome in Chronic Obstructive Pulmonary Disease: Role of Natural Products Against Microbial Pathogens

The "microbiome" is the operative term to refer to a collection of all taxa constituting microbial communities, such as bacteria, archaea, fungi and protists (originally microbiota). The microbiome consists of the indigenous microbial communities and of the host environment that they inhabit. Actually, it has been shown that there is a close relationship between the microbiome and human health and disease condition. Although, initially, the lung was considered sterile, actually, the existence of a healthy lung microbiome is usually accepted. Lung microbiome changes are reported in Chronic Obstructive Pulmonary Disease (COPD) and in its exacerbation. Viral and bacterial infections of the respiratory system are a major cause of COPD exacerbations (AECOPD) leading to increased local and systemic inflammation. Detection rates of virus in AECOPD are variable between 25-62% according to the detection method. The study of human airway and lung disease virome is quite recent and still very limited. The purpose of this review is to summarize recent findings on the lung microbiome composition with a special emphasis on virome in COPD and in AECOPD. Some drugs of natural origins active against resistant bacteria and virus are described.

Immunopathogenesis of COVID-19 and early immunomodulators

The novel coronavirus disease 2019 (COVID-19) is spreading globally. Although its etiologic agent is discovered as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), there are many unsolved issues in COVID-19 and other infectious diseases. The causes of different clinical phenotypes and incubation periods among individuals, species specificity, and cytokine storm with lymphopenia as well as the mechanism of damage to organ cells are unknown. It has been suggested that in viral pneumonia, virus itself is not a direct cause of acute lung injury; rather, aberrant immune reactions of the host to the insults from viral infection are responsible. According to its epidemiological and clinical characteristics, SARS-CoV-2 may be a virus with low virulence in nature that has adapted to the human species. Current immunological concepts have limited ability to explain such unsolved issues, and a presumed immunopathogenesis of COVID-19 is presented under the proteinhomeostasis-system hypothesis. Every disease, including COVID-19, has etiological substances controlled by the host immune system according to size and biochemical properties. Patients with severe pneumonia caused by SARS-CoV-2 show more severe hypercytokinemia with corresponding lymphocytopenia than patients with mild pneumonia; thus, early immunomodulator treatment, including corticosteroids, has been considered. However, current guidelines recommend their use only for patients with advanced pneumonia or acute respiratory distress syndrome. Since the immunopathogenesis of pneumonia may be the same for all patients regardless of age or severity and the critical immune-mediated lung injury may begin in the early stage of the disease, early immunomodulator treatment, including corticosteroids and intravenous immunoglobulin, can help reduce morbidity and possibly mortality rates of older patients with underlying conditions.

Laboratory characteristics of patients infected with the novel SARS-CoV-2 virus

A subgroup of COVID-19 patients develop very severe disease with requirement for ICU treatment, ventilation, and ECMO therapy. Laboratory tests indicate that the immune and clotting system show marked alterations with hyper-activation, hyper-inflammation, cytokine storm development. Furthermore, organ-specific biomarkers demonstrate the involvement of cardiac muscle, kidney, and liver dysfunction in many patients. In this article the use of laboratory biomarkers is discussed with regard to their use for diagnosis, disease progression, and risk assessment.