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

Defining age-specific reference intervals for biomarkers distinguishing bacterial from viral infection in paediatrics

Differentiating bacterial from viral infections in children is a common clinical challenge. Novel host immune biomarkers have the potential to aid thediagnosis of infection aetiology and identify children who require antibiotics. Data on novel infection biomarkers gender and age-specific correlations, and reference intervals in healthy paediatrics is lacking. This study reports the plasma levels of three novel biomarkers that can aid in the differentiation of bacterial and viral infection in a healthy group of paediatrics. The levels of (Interferon-Gamma Inducible Protein 10 kDa (IP-10), Lipocalin-2 (LCN2) and TNF-Related Apoptosis-Inducing Ligand (TRAIL) were quantified in 199 plasma samples from healthy paediatrics aged 2 to 16 years old from across the UK. Reference intervals (2.5th and 97.5th) were determined, and biomarker levels were examined for sex and age associations. Reference intervals for IP-10, LCN2 and TRAIL for ages 2-16 years were 36.7-168.1 pg/ml, 14.2-123.3 ng/ml, 57.4-71.4 pg/ml respectively. No biomarker showed an association with sex and IP-10 did not show any association with age. TRAIL levels had a weak continuous negative correlation with age and LCN2 levels had a continuous positive correlation with age. Specific cut-offs for LCN2 in two age categories were identified, while TRAIL did not require age partitions. This study provides age-appropriate reference intervals for three biomarkers of infection in healthy children. These findings have the potential to improve the impact of future research on these biomarkers, the accuracy of clinical decision-making in children with infection, paediatric patient care and outcomes, and antimicrobial stewardship.

Recent updates of interferon-derived myxovirus resistance protein A as a biomarker for acute viral infection

BACKGROUND

Antibiotic resistance (AMR) remains a global public health threat with a high burden in sub-Saharan countries. The overuse of antimicrobials in the clinical setting is the main factor for the spread of antibiotic resistance. Diagnostic uncertainty in differentiating between bacterial and viral infections is the major contributor to antimicrobial overuse. The available biomarkers lack specificity in guiding clinicians to make antibiotic decisions and only estimate bacterial infection.

MAIN BODY

Myxovirus resistance (Mx) proteins are a type of interferon (IFN)-inducible protein that belongs to the dynamin superfamily of large guanine triphosphates (GTPases) involved in broad antiviral responses. Myxovirus resistance protein A (MxA) is a host-derived biomarker with antiviral properties against various viruses. It is induced by IFN I and IFN III as part of the innate immune response. Its basal level is < 15 ng/ml and elevated levels are detectable 1-2 h after IFN induction and remain detectable in serum up to 10 days after viral infection. Increased levels in the blood are associated with viral infection and remain low during bacterial infections. This biomarker showed promising performance in diagnosing undifferentiated febrile patients with respiratory tract infections. In this review, we discuss the role of Mx proteins, specifically MxA, in diagnosing acute viral infections, including how they are induced and their potential as diagnostic tools.

METHODS

A comprehensive electronic search was conducted in Scopus and Medline (using the PubMed interface) regarding myxovirus resistance protein A as a biomarker for acute viral infection. In the search strategy, English language was used without date restriction. Manual search was also performed when appropriate.

CONCLUSIONS

Elevated MxA combined with other biomarkers, such as CRP and PCT, is a promising tool for identifying patients with viral infections. Therefore, incorporating MxA in the existing point of care formats help to improve the antibiotic stewardship programs and future randomized controlled trials are recommended to evaluate its utility in medical practice.

Accuracy of the diagnosis of pneumonia in Canadian pediatric emergency departments: A prospective cohort study

BACKGROUND

The diagnosis of pediatric pneumonia and determination of the likely pathogen are complicated as the clinical picture overlaps with other respiratory illnesses, interpretation of radiographs is subjective, and laboratory results are rarely diagnostic. This study was designed to describe the relative rates of bacterial and viral pneumonia in the pediatric Emergency Department (ED), determine the accuracy of pediatric ED physicians' ability to diagnose pneumonia and distinguish bacterial from viral etiology, and to determine clinical and laboratory predictors of bacterial pneumonia.

METHODS

Children 3 months to 16 years of age presenting to seven Canadian pediatric EDs before the COVID-19 pandemic with fever and cough who had a chest radiograph performed for possible pneumonia were enrolled and underwent standardized clinical investigations. An expert panel was convened and reached a Consensus Diagnosis of typical or atypical bacterial pneumonia, viral pneumonia or not pneumonia for each case.

RESULTS

The expert panel assessed 247 cases with the Consensus Diagnosis being typical bacterial pneumonia (N = 44(18%)), atypical bacterial pneumonia (N = 18(7%)), viral pneumonia (N = 46(19%)) and no pneumonia (N = 139(56%)). Treating ED physician diagnoses were typical bacterial pneumonia (N = 126(51%)), atypical bacterial pneumonia (N = 3(1%)), viral pneumonia (N = 10(4%)) and no pneumonia (N = 108(44%)) with low agreement between a diagnosis of bacterial pneumonia by the ED physician and the panel's Consensus Diagnosis (Kappa 0.15 (95% CI 0.08, 0.21)). Cut off values that predicted bacterial pneumonia as the Consensus Diagnosis were ESR ≥ 47 mm/hour, CRP ≥ 42 mg/L and procalcitonin ≥0.85 ng/m. Age greater than 5 years and cough for 5 or more days also predict bacterial pneumonia.

CONCLUSION

In this cohort, pediatric ED physicians over-diagnosed typical bacterial pneumonia and underdiagnosed viral and atypical bacterial pneumonia. Bacterial pneumonia is most likely in children over 5 years of age, with cough for 5 or more days and/or with elevated inflammatory markers.

The Association of the MeMed BV Test With Radiographic Pneumonia in Children

BACKGROUND

The MeMed BV Test produces a score that increases with increasing likelihood of bacterial infection. We evaluated its association with radiographic pneumonia in children.

METHODS

We performed a secondary analysis of a multicenter prospective study of febrile children 90 days to 18 years presenting to an emergency department. We evaluated the association of the MeMed BV test with radiographic pneumonia in adjusted logistic regression models.

RESULTS

Of 182 children, 74 (41%) had radiographic pneumonia. Among children with a high likelihood of having viral illness per the BV test, 26% had radiographic pneumonia; this increased to 64% among those with a BV test which indicated a high likelihood of bacterial infection. The sensitivity and specificity for radiographic pneumonia when using a BV test classification of moderate or high likelihood of bacterial infection were 60.8% and 62.0%, respectively. A BV test indicating the highest likelihood of bacterial infection had 23.61 higher adjusted odds (95% confidence interval 6.30-88.6) of radiographic pneumonia. The most common radiographic finding among children classified as having a high likelihood of viral infection by the BV test was interstitial opacities. The most common finding among children classified as having a high likelihood of bacterial infection were infiltrates. Except for antibiotic use, clinical outcomes occurred in similar proportions by BV category.

CONCLUSIONS

Children with moderate to high likelihoods of bacterial infection on the BV test had higher odds of radiographic pneumonia. Apart from antibiotic use, the test was not significantly associated with clinical outcomes in this study.

Overview of Pediatric Procalcitonin Testing Patterns in a Tertiary Care Children's Hospital

The use of procalcitonin (PCT) has grown over the past decade with increasing reliance on the test to rule out bacterial infection. We retrospectively reviewed the medical records of children <18 years old hospitalized at a tertiary care children's hospital from 2017 to 2019 who had PCT testing performed during their admission. Of 4135 PCT levels collected on 1530 children, 982 (23.7%) were diagnostically low and 1993 (48.1%) were diagnostically elevated. Pediatric intensive care, with 6% of total hospital patients, obtained 41.4% of tests. Thirty-one (2%) patients had an average of 27 PCT levels per patient, accounting for 20% of all tests. Many children had symptoms for which testing is not indicated (eg, skin complaints). The differences in PCT testing by service, inappropriate patterns of repeat testing, and testing performed in patients for whom it is not indicated may identify targets for diagnostic stewardship.

Evaluation of FebriDx® for the management of children with acute febrile respiratory infection

INTRODUCTION

Acute respiratory infections (ARI) are a common cause of inappropriate antibiotic prescription (ATB) in pediatrics. FebriDx® is a rapid diagnostic test that differentiates between viral and bacterial infections. The objective is to analyse the impact of FebriDx® on ATB prescription when managing febrile ARI.

METHODS

Prospective study carried out in patients aged 1-<18 years with febrile ARI in the emergency department. FebriDx® was performed and the impact on management was evaluated at follow-up.

RESULTS

A total of 216 patients were included. Clinical assessment and FebriDx® result coincided coincided in 174 (80.5%) cases. A modification of the initial therapeutic plan was made in 22 (52.4%) of the 42 discordant ones (10.2% of the overall patients). In pneumonia the impact was 34.5%; in all cases it involved not prescribing ATB.

CONCLUSIONS

FebriDx® could be a useful tool in the management of pediatric patients with febrile ARI to optimize ATB prescription.

Procalcitonin and Presepsin as Markers of Infectious Respiratory Diseases in Children: A Scoping Review of the Literature

INTRODUCTION

Procalcitonin and presepsin have been suggested to be able to discriminate bacterial and viral infections, also in children. This scoping review aims to better explore the available evidence around the potential role of these biomarkers in the subgroup of children with respiratory infectious diseases.

METHODS

We performed a systematic scoping review of studies published until March 2023 in the following bibliographic databases: PubMed, EMBASE, Cochrane and SCOPUS.

RESULTS

In children with bacterial infection, procalcitonin values ranged from 0.5 ng/mL to 8.31 ng/dL, while in those hospitalized in an intensive care unit ranged from 0.6 ng/dL to 452.8 ng/dL with PCR from 2 ng/dL to 51.7 ng/dL. In children with viral infections, procalcitonin value values ranged from 0.2 ng/dL to 0.84 ng/dL, while in those hospitalized in an intensive care unit ranged from 0.61 ng/dL to 46.6 ng/dL. No studies on presepsin in children with respiratory infections were retrieved.

CONCLUSIONS

Although the available literature is highly heterogeneous, evidence does not suggest a role of procalcitonin in accurately differentiating bacterial and viral infections in children with respiratory infections. In future, new approaches based on multiple markers may better help determine which febrile children require antibiotics.

Multiplex PCR and Antibiotic Use in Children with Community-Acquired Pneumonia

Antibiotics are frequently prescribed to children with pneumonia, although viruses are responsible for most cases. We aimed to evaluate the impact of multiplex polymerase chain reaction (mPCR) on antibiotic use. We conducted a prospective study of children under 14 years of age admitted for suspected viral pneumonia, from October 2019 to June 2022 (except March-November 2020). A mPCR respiratory panel (FilmArray® 2plus, bioMérieux, Marcy-l'Étoile, France) was performed within 72 h of admission. Patients with positive reverse transcription PCR for respiratory syncytial virus, influenza, or SARS-CoV-2 were excluded. We compared the patients with historical controls (2017-2018) who had suspected viral pneumonia but did not undergo an aetiological study. We included 64 patients and 50 controls, with a median age of 26 months. The respiratory panel detected viral pathogens in 55 patients (88%), including 17 (31%) with co-infections. Rhinovirus/enterovirus (n = 26) and human metapneumovirus (n = 22) were the most common pathogens, followed by adenovirus and parainfluenza (n = 10). There were no statistically significant differences in the total antibiotic consumption (83% of cases and 86% of controls) or antibiotics given for ≥72 h (58% vs. 66%). Antibiotics were prescribed in 41% of the cases and 72% of the controls at discharge (p = 0.001). Ampicillin was the most commonly prescribed antibiotic among the patients (44% vs. 18% for controls, p = 0.004), while azithromycin was the most commonly prescribed among the controls (19% vs. 48% for patients and controls, respectively; p = 0.001). Our findings underscore the need for additional interventions alongside molecular diagnosis to reduce antibiotic usage in paediatric community-acquired pneumonia.

The Diagnostic Association of Radiological and Clinicopathological Parameters in Community-Acquired Pneumonia in Children: A Cross-Sectional Study

Background Globally, pneumonia is one of the significant causes of death in children under the age of five years. Assessment of disease severity is essential for clinical decision-making. Clinicians in resource-limited settings use the WHO Integrated Management of Childhood Illness (IMNCI) guidelines to diagnose and treat pneumonia. Chest X-rays and blood biomarkers are frequently performed in children presenting with pneumonia, but their role in clinical decision-making is limited. Objective To evaluate the association of chest X-ray results, clinical parameters, and blood inflammatory biomarkers with the severity of community-acquired pneumonia (CAP) in children to decide which tests are helpful in accurately classifying the severity of pneumonia. Methods This cross-sectional, analytical study was conducted at the Combined Military Hospital, Lahore, among 421 children aged two months to five years who were admitted with complaints of cough and difficulty breathing and were COVID-19 negative. Data was collected through a structured questionnaire, including demographic information and clinical categorization of pneumonia severity using WHO criteria, SpO2 levels, chest X-rays, complete blood count (CBC), and C-reactive protein (CRP) levels obtained within 24 hours of admission. Statistical evaluation of 323 children was done using SPSS version 26, and analysis of variance (ANOVA), chi-square test, and Fisher's exact test were applied to determine statistical significance. p-Value <0.05 was considered significant. Results The median age of the study population was eight months (IQR: 3-20 months); 113 (33.1%) were girls and 127 (37.2%) were underweight children. Eighteen (5.3%) patients had no pneumonia, 245 (71.8%) patients had non-severe pneumonia, and 78 (22.9%) patients had severe pneumonia. The clinical features of severe pneumonia were more common in children with radiologic findings of alveolar CAP than non-alveolar CAP (36.2% and 20%, respectively, p: 0.05). A higher percentage of patients with alveolar CAP had CRP >6 mg/dL than non-alveolar CAP (69.9% and 35%, respectively, p < 0.001). Patients with undernutrition (WAZ <-2 SD), hypoxemia (SpO2 <95%), and having CRP >6 mg/dL were associated with clinical features of severe pneumonia (46.1% vs. 33.8%, 100% vs 47.3%, and 67.9% vs 48.5%, respectively, p < 0.05). A significantly greater frequency of a bilateral multifocal distribution (p = 0.020), and the involvement of the right paracardiac region (p = 0.043) and the left lower lobe (p = 0.007) in those with severe pneumonia was observed. Conclusion Clinical diagnosis of pneumonia, along with the assessment of risk factors, including undernutrition and hypoxemia, should be adequate to diagnose pneumonia in children. Chest X-rays and CRP levels can be helpful in hospitalized children for whom physicians have difficulty deciding about antibiotic prescriptions, but their role in routinely classifying the severity of pneumonia in children is limited.

Circulating markers of neutrophil activation and lung injury in pediatric pneumonia in low-resource settings

Diagnostic biomarkers for childhood pneumonia could guide management and improve antibiotic stewardship in low-resource settings where chest x-ray (CXR) is not always available. In this cross-sectional study, we measured chitinase 3-like protein 1 (CHI3L1), surfactant protein D (SP-D), lipocalin-2 (LCN2), and tissue inhibitor of metalloproteinases-1 (TIMP-1) in Ugandan children under the age of five hospitalized with acute lower respiratory tract infection. We determined the association between biomarker levels and primary end-point pneumonia, indicated by CXR consolidation. We included 89 children (median age 11 months, 39% female). Primary endpoint pneumonia was present in 22 (25%). Clinical signs were similar in children with and without CXR consolidation. Broad-spectrum antibiotics (ceftriaxone) were administered in 83 (93%). Levels of CHI3L1, SP-D, LCN2 and TIMP-1 were higher in patients with primary end-point pneumonia compared to patients with normal CXR or other infiltrates. All markers were moderately accurate predictors of primary end-point pneumonia, with area under receiver operator characteristic curves of 0.66-0.70 (p<0.05 for all markers). The probability of CXR consolidation increased monotonically with the number of markers above cut-off. Among 28 patients (31%) in whom all four markers were below the cut-off, the likelihood ratio of CXR consolidation was 0.11 (95%CI 0.015 to 0.73). CHI3L1, SP-D, LCN2 and TIMP-1 were associated with CXR consolidation in children with clinical pneumonia in a low-resource setting. Combinations of quantitative biomarkers may be useful to safely withhold antibiotics in children with a low probability of bacterial infection.

Hemoglobin and Its Z Score Reference Intervals in Febrile Children: A Cohort Study of 98,572 Febrile Children

OBJECTIVES

Febrile disease and age of children were associated with a variation in hemoglobin (Hb) level. Both CRP and Hb serve as laboratory markers that offer valuable insights into a patient's health, particularly in relation to inflammation and specific medical conditions. Although a direct correlation between CRP and Hb levels is not established, the relationship between these markers has garnered academic attention and investigation. This study aimed to determine updated reference ranges for Hb levels for age and investigated its correlation with CRP in febrile children under the age of 18.

METHODS

This is a cohort study of in Chang Gung Memorial Hospitals conducted from January 2010 to December 2019. Blood samples were collected from 98,572 febrile children who were or had been admitted in the pediatric emergency department. The parameters of individuals were presented as the mean ± standard deviation or 2.5th and 97.5th percentiles. We also determined the variation of Hb and Z score of Hb between CRP levels in febrile children.

RESULT

We observed that the Hb levels were the highest immediately after birth and subsequently underwent a rapid decline, reaching their lowest point at around 1-2 months of age, and followed by a steady increment in Hb levels throughout childhood and adolescence. In addition, there was a significant and wide variation in Hb levels during the infant period. It revealed a significant association between higher CRP levels and lower Hb levels or a more negative Z score of Hb across all age subgroups. Moreover, in patients with bacteremia, CRP levels were higher, Hb concentrations were lower, and Z scores of Hb were also lower compared to the non-bacteremia group. Furthermore, the bacteremia group exhibited a more substantial negative correlation between CRP levels and a Z score of Hb (r = -0.41, p < 0.001) compared to the non-bacteremia group (r = -0.115, p < 0.049).

CONCLUSION

The study findings revealed that the Hb references varied depending on the age of the children and their CRP levels. In addition, we established new reference values for Hb and its Z scores and explore their relationship with CRP. It provides valuable insights into the Hb status and its potential association with inflammation in febrile pediatric patients.

Salivary Biomarkers to Differentiate between Streptococcus pneumoniae and Influenza A Virus-Related Pneumonia in Children

Community-acquired pneumonia (CAP) is common among children and can be fatal in certain conditions. In children, CAP can be caused by viral or bacterial infections. Identification of pathogens can help select appropriate therapeutic strategies. Salivary analysis may be a potential diagnostic tool because it is noninvasive, patient-friendly, and easy to perform in children. A prospective study was conducted in children with pneumonia admitted to a hospital. Salivary samples from patients with definite Streptococcus pneumoniae and influenza A strains were used for gel-free (isobaric tag for relative and absolute quantitation (iTRAQ)) proteomics. No statistically significant difference was detected in salivary CRP levels between Streptococcus pneumoniae and influenza A pneumonia in children. Several potential salivary biomarkers were identified using gel-free iTRAQ proteomics to differentiate pneumonia from Streptococcus pneumoniae or influenza A virus infections in pediatric patients. ELISA validated that Streptococcus pneumoniae group has a higher abundance of salivary alpha 1-antichymotrypsin than those in the influenza A group. Whether these salivary biomarkers can be used to distinguish other bacteria from viral pneumonia requires further verification.

A retrospective observational study of biomarker levels and severity assessment in pediatric community-acquired pneumonia

METHODS

A retrospective chart review was conducted on children (aged 60 days to 18 years) diagnosed with CAP, and admitted to a regional, tertiary hospital (Charleston, WV, USA) for 3 years (2015-2018). Patients were stratified into 2 severity cohorts, mild (no ICU care), and moderate/severe (required ICU care). Biomarker values were then compared between the severity cohorts and area under the curve (AUC), and cut-off values and performance characteristics were calculated.

RESULTS

A total of 108 patients met inclusion criteria with 46% having moderate/severe CAP. Elevated levels of CRP (51.7 mg/L in mild vs. 104.8 mg/L in moderate/severe, P = .003, PCT (0.29 ng/ml in mild vs. 4.02 ng/mL in moderate/severe, P = .001) and band counts (8% in mild vs. 15% moderate/severe, P = .009) were associated with increased pneumonia severity. In predicting moderate/severe CAP, PCT had the highest AUC of 0.77 (P = .001) followed by bands AUC of 0.69 (P = .009) and CRP AUC of 0.67 (P = .003). Cut-off for PCT of 0.55 ng/mL had a sensitivity of 83% and a specificity of 65%. Cut-off level of 53.1 mg/L for CRP had a sensitivity of 79% and specificity of 52%. Cut off level of 12.5% bands had a sensitivity of 61% and specificity of 71%. In a multivariable model controlled for patient demographics and other biomarker levels, only PCT levels significantly predicted moderate/severe CAP (adjusted odds ratio: 1.40 [95% CI, 1.14-1.73], P = .002).

CONCLUSION

Biomarkers, in particular PCT, obtained early in hospitalization may perform as possible predictors for CAP severity in children and be beneficial in guiding CAP management. However, biomarkers in pneumonia should not drive severity assessment or patient management independent of clinical presentation.

Prognostic value of blood urea nitrogen-to-serum albumin ratio for mortality of pneumonia in patients receiving glucocorticoids: Secondary analysis based on a retrospective cohort study

INTRODUCTION

Previous studies have revealed that blood urea nitrogen-to-serum albumin ratio (BUN/ALB) is one of major risk factors of mortality in pneumonia. However, there are fewer scientific research about the correlation between BUN/ALB ratio and outcome of pneumonia in patients receiving glucocorticoids. This study was undertaken to explore the prognostic value of BUN/ALB ratio for mortality of pneumonia in patients receiving glucocorticoids.

METHODS

The present study was a retrospective cohort study. 1397 subjects receiving glucocorticoids alone or glucocorticoids and other immunosuppressants from six secondary and tertiary academic hospitals in China were analyzed. The endpoint of the study was 30-day mortality. It was noted that the entire study was completed by Li et al. and uploaded the data to the DATADRYAD website. The author only used this data for secondary analysis.

RESULTS

After adjusting potential confounders (age, sex, WBC, persistent lymphocytopenia, PLT, ALT, AST, Cr, high-dose steroid use, and COPD), non-linear relationship was detected between BUN/ALB ratio and 30-day mortality, whose point was 0.753. The effect sizes and the confidence intervals on the left and right sides of inflection point were 23.110 (7.157, 74.623) and 0.410 (0.074, 2.283), respectively. Subgroup analysis revealed the positive association was stronger among subjects with connective tissue disease.

CONCLUSIONS

The relationship between BUN/ALB ratio and 30-day mortality of pneumonia in patients receiving glucocorticoids is non-linear. BUN/ALB ratio is positively related with 30-day mortality when BUN/ALB ratio is less than 0.753.