Elevated inflammatory markers combined with positive pneumococcal urinary antigen are a good predictor of pneumococcal community-acquired pneumonia in children

Community-Acquired Pneumonia in Children

ABSTRACT

Community-acquired pneumonia (CAP) is the most common cause of childhood mortality globally. In the United States, CAP is a leading cause of pediatric hospitalization and antibiotic use and is associated with substantial morbidity. There has been a dramatic shift in microbiological etiologies for CAP in children over time as pneumococcal pneumonia has become less common and viral etiologies have become predominant. There is no commonly agreed on approach to the diagnosis of CAP in children. When indicated, antimicrobial treatment should consist of narrow-spectrum antibiotics. In this article, we will describe the current understanding of the microbiological etiologies, clinical presentation, diagnostic approach, risk factors, treatment, and future directions in the diagnosis and management of pediatric CAP.

Novel care pathway to optimise antimicrobial prescribing for uncomplicated community-acquired pneumonia: study protocol for a prospective before-after cohort study in the emergency department of a tertiary care Canadian children's hospital

INTRODUCTION

Evidence-based recommendations for paediatric community-acquired pneumonia (CAP) diagnosis and management are needed. Uncomplicated CAP is often caused by respiratory viruses, especially in younger children; these episodes self-resolve without antibiotic treatment. Unfortunately, there are no clinical criteria that reliably discriminate between viral and bacterial disease, and so the majority of children diagnosed with CAP are given antibiotics-even though these will often not help and may cause harm. We have developed a novel care pathway that incorporates point-of-care biomarkers, radiographic patterns, microbiological testing and targeted follow-up. The primary study objective is to determine if the care pathway will be associated with less antimicrobial prescribing.

METHODS AND ANALYSIS

A prospective, before-after, study. Previously well children aged≥6 months presenting to a paediatric emergency department (ED) that have at least one respiratory symptom/sign, receive chest radiography, and are diagnosed with CAP by the ED physician will be eligible. Those with medical comorbidities, recently diagnosed pulmonary infection, or ongoing fever after≥4 days of antimicrobial therapy will be excluded. In the control (before) phase, eligible participants will be managed as per the standard of care. In the intervention (after) phase, eligible participants will be managed as per the novel care pathway. The primary outcome will be the proportion of participants in each phase who receive antimicrobial treatment for CAP. The secondary outcomes include: clinical cure; re-presentation to the ED; hospitalisation; time to resolution of symptoms; drug adverse events; caregiver satisfaction; child absenteeism from daycare/school; and caregiver absenteeism from work.

ETHICS AND DISSEMINATION

All study documentation has been approved by the Hamilton Integrated Research Ethics Board and informed consent will be obtained from all participants. Data from this study will be presented at major conferences and published in peer-reviewed publications to facilitate collaborations with networks of clinicians experienced in the dissemination of clinical guidelines.

TRIAL REGISTRATION NUMBER

NCT05114161.

Rapid Diagnostic Tests to Guide Case Management of and Improve Antibiotic Stewardship for Pediatric Acute Respiratory Illnesses in Resource-Constrained Settings: a Prospective Cohort Study in Southwestern Uganda

Pediatric acute respiratory illness (ARI) is one of the most common reasons for evaluation at peripheral health centers in sub-Saharan Africa and is frequently managed based on clinical syndrome alone. Although most ARI episodes are likely caused by self-limited viral infections, the majority are treated with antibiotics. This overuse contributes to the development of antimicrobial resistance. To evaluate the preliminary feasibility and potential impact of adding pathogen-specific and clinical biomarker diagnostic testing to existing clinical management algorithms, we conducted a prospective, observational cohort study of 225 children presenting with malaria-negative, febrile ARI to the outpatient department of a semi-urban peripheral health facility in southwestern Uganda from October 2019 to January 2020. In addition to routine clinical evaluation, we performed influenza and Streptococcus pneumoniae antigen testing and measured levels of C-reactive protein, procalcitonin, and lactate in the clinic's laboratory, and conducted a follow-up assessment by phone 7 days later. Almost one-fifth of participants (40/225) tested positive for influenza. Clinical biomarker measurements were low with C-reactive protein of >40 mg/L in only 11% (13/222) of participants and procalcitonin >0.25 ng/mL in only 13% (16/125). All but two children received antibiotic treatment; only 3% (7/225) were admitted. At follow-up, 59% (118/201) of caregivers reported at least one persistent symptom, but fever had resolved for all children. Positive influenza testing was associated with persistent symptoms. In summary, we demonstrate that simple, rapid pathogen-specific testing and biomarker measurement are possible in resource-limited settings and could improve syndromic management and, in turn, antibiotic stewardship. IMPORTANCE Globally, respiratory illness is one of the most common reasons that children seek care. It is often treated inappropriately with antibiotics, which can drive the development of antibiotic resistance. In resource-rich settings, testing for specific pathogens or measurement of clinical biomarkers, such as procalcitonin and C-reactive protein, is often employed to help determine which children should receive antibiotics. However, there are limited data on the use of these tests in resource-constrained, outpatient contexts in sub-Saharan Africa. We enrolled children with respiratory illness presenting to a clinic in southwestern Uganda and performed testing for influenza, Streptococcus pneumoniae, C-reactive protein, and procalcitonin on-site. Almost all children received antibiotics. We demonstrate that employing clinical algorithms that include influenza and clinical biomarker testing could significantly decrease antibiotic prescriptions. Our study therefore provides preliminary data to support the feasibility and potential utility of diagnostics to improve management of respiratory illness in resource-constrained settings.

External validation of the RISC, RISC-Malawi, and PERCH clinical prediction rules to identify risk of death in children hospitalized with pneumonia

BACKGROUND

Existing scores to identify children at risk of hospitalized pneumonia-related mortality lack broad external validation. Our objective was to externally validate three such risk scores.

METHODS

We applied the Respiratory Index of Severity in Children (RISC) for HIV-negative children, the RISC-Malawi, and the Pneumonia Etiology Research for Child Health (PERCH) scores to hospitalized children in the Pneumonia REsearch Partnerships to Assess WHO REcommendations (PREPARE) data set. The PREPARE data set includes pooled data from 41 studies on pediatric pneumonia from across the world. We calculated test characteristics and the area under the curve (AUC) for each of these clinical prediction rules.

RESULTS

The RISC score for HIV-negative children was applied to 3574 children 0-24 months and demonstrated poor discriminatory ability (AUC = 0.66, 95% confidence interval (CI) = 0.58-0.73) in the identification of children at risk of hospitalized pneumonia-related mortality. The RISC-Malawi score had fair discriminatory value (AUC = 0.75, 95% CI = 0.74-0.77) among 17 864 children 2-59 months. The PERCH score was applied to 732 children 1-59 months and also demonstrated poor discriminatory value (AUC = 0.55, 95% CI = 0.37-0.73).

CONCLUSIONS

In a large external application of the RISC, RISC-Malawi, and PERCH scores, a substantial number of children were misclassified for their risk of hospitalized pneumonia-related mortality. Although pneumonia risk scores have performed well among the cohorts in which they were derived, their performance diminished when externally applied. A generalizable risk assessment tool with higher sensitivity and specificity to identify children at risk of hospitalized pneumonia-related mortality may be needed. Such a generalizable risk assessment tool would need context-specific validation prior to implementation in that setting.

Urinary Proadrenomedullin and Disease Severity in Children With Suspected Community-acquired Pneumonia

BACKGROUND

Plasma proadrenomedullin (proADM) is a promising biomarker to predict disease severity in community-acquired pneumonia (CAP). Urinary biomarkers offer advantages over blood, including ease of collection. We evaluated the association between urinary proADM and disease severity in pediatric CAP.

METHODS

We performed a prospective cohort study of children 3 months to 18 years with CAP. Urinary proADM/creatinine (Cr) was calculated. Disease severity was defined as: mild (discharged home), mild-moderate (hospitalized but not moderate-severe or severe), moderate-severe (eg, hospitalized with supplemental oxygen and complicated pneumonia) and severe (eg, vasopressors and invasive ventilation). Outcomes were examined using logistic regression within the cohort with suspected CAP and in a subset with radiographic CAP.

RESULTS

Of the 427 children included, higher proADM/Cr was associated with increased odds of severe disease compared with nonsevere disease [suspected CAP, odds ratio (OR) 1.02 (95% confidence interval (CI) 1.003, 1.04); radiographic CAP, OR 1.03 (95% CI 1.01, 1.06)] when adjusted for other covariates. ProADM/Cr had an area under the receiver operating characteristic curve of 0.56 (threshold 0.9 pmol/mg) to differentiate severe from nonsevere disease in suspected CAP and 0.65 in radiographic CAP (threshold 0.82 pmol/mg). Healthy controls had less proADM in their urine (median, 0.61 pmol/mg) compared with suspected (0.87 pmol/mg, P = 0.018) and radiographic (0.73 pmol/mg, P = 0.016) CAP.

CONCLUSIONS

Urinary proADM/Cr ratio measured at the time of emergency department visit was statistically associated with the development of severe outcomes in children with CAP, with stronger discriminatory performance in radiographic disease.

Diagnostic accuracy of procalcitonin for bacterial pneumonia in children - a systematic review and meta-analysis

Objective: The predictive role of procalcitonin for childhood bacterial pneumonia, a leading cause of death, is unclear. We aimed to evaluate the diagnostic accuracy of procalcitonin for childhood bacterial pneumonia.Methods: Major bibliographic databases were searched from inception through September 2019 using pre-defined index terms, including 'procalcitonin,' 'pneumonia' and 'children'. The study is reported according to Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies. Meta-analyses of the diagnostic accuracy and odds ratio of procalcitonin for bacterial pneumonia were conducted along with subgroup analyses for different cut-offs of procalcitonin. The Quality Assessment of Diagnostic Accuracy Studies 2 instrument was used to assess the methodologic quality of eligible studies.Results: Twenty-five studies (with 2,864 patients) showed that procalcitonin for bacterial pneumonia had an overall sensitivity of 0.64 (95% confidence interval: 0.53-0.74), specificity of 0.72 (95% confidence interval: 0.64-0.79), positive likelihood ratio of 2.3 (95% confidence interval: 1.8-3.0) and negative likelihood ratio of 0.50 (95% confidence interval: 0.38-0.66), and Area Under the Receiver Operating Characteristics of 0.74 (95% confidence interval: 0.70-0.78). Using a cut-off of 0.5 ng/ml, Procalcitonin had a sensitivity of 0.68 (95% confidence interval: 0.50-0.82), specificity of 0.60 (95% confidence interval: 0.47-0.72), and Area Under the Receiver Operating Characteristics of 0.68 (95% confidence interval: 0.64-0.72). Using a cut-off of 2 ng/ml, procalcitonin had a sensitivity of 0.59 (95% confidence interval: 0.40-0.76), specificity of 0.71 (95% confidence interval: 0.58-0.81), and AUROC curve of 0.71 (95% confidence interval: 0.67-0.75). Elevated procalcitonin was not associated with increased odds of bacterial pneumonia (odds ratio: 1.36, 95% confidence interval: 0.81-1.92, p = .18). Quality assessment found minimal concerns for bias or applicability.Conclusions: Given the moderate diagnostic accuracy of procalcitonin for bacterial pneumonia, we recommend that procalcitonin be used in conjunction with other findings for management and disposition of children with pneumonia.

Community-Acquired Pneumonia

Community-acquired pneumonia is an infection of the small airways and pulmonary parenchyma that develops in the outpatient setting. Despite the development of new antibiotics and vaccines, pneumonia is still a disease that occurs frequently in children under 5 years of age and is one of the main causes of mortality, especially in developing countries. The biggest challenge in treating pneumonia is to determine the agent, which depends on age, disease severity, immunological condition, geographic location, epidemiological situation, and immunizations. The classic clinical picture presents with fever, coughing, and difficulty in breathing. The physical examination shows tachypnea, reduced breath sounds, and fine crackles. Wheezing may be present in infants with viral pneumonia. The chest X-ray is considered an important tool to confirm the disease diagnosis and may guide specific treatment. Acute-phase reactants have a low sensitivity and specificity to distinguish between virus and bacteria. Microbiological identification does not have a clinical impact for most children with community-acquired pneumonia. Bronchoalveolar lavage may be considered for immunocompromised patients. Antibiotic treatment is empirical based on the best possible etiology, depending on the patient’s age and epidemiological timing. Amoxicillin is the treatment of choice for Streptococcus pneumoniae , and azithromycin is preferred for Mycoplasma pneumoniae.

[Place of biomarkers in the management of pulmonary infections]

INTRODUCTION

The management of acute lower respiratory tract infections and, in particular, the decision whether or not to commence antibiotic therapy, still remains difficult in the absence of reliable clinical or radiological criteria allowing confident distinction between bacterial and viral infections. Numerous biomarkers have been developed to help the clinician in his/her diagnostic and therapeutic approach, but the role and significance of each has not been clearly defined.

BACKGROUND

Though procalcitonin (PCT) or C-reactive protein (CRP) seem equal in helping the clinician to decide whether to commence antibiotic therapy or not during the course of an exacerbation of asthma or chronic obstructive pulmonary disease (COPD), PCT is currently the most useful biomarker to distinguish sepsis from other causes of inflammation and to determine the bacterial or viral origin of a pneumonia.

OUTLOOK

The ability of PCT to reduce the global exposure to antibiotics remains uncertain and the results of randomised trials are contradictory.

CONCLUSIONS

Prescription algorithms involving PCT may be used without increased risk for patients even though clinical signs of severity remain important. Changes in PCT also have a prognostic value in identifying those patients with unfavourable outcome.

Use of procalcitonin in the diagnosis of tuberculosis in infants and preschool children

Normal procalcitonin (PCT) levels have been reported in adult pulmonary tuberculosis (TB) but have not been previously investigated in children. We aimed to assess PCT levels at diagnosis of TB in young children in a low-burden setting. In a cross-sectional observational study in a referral pediatric center in Barcelona (Spain), we assessed the value of PCT and other inflammatory markers (leucocyte counts, C-reactive protein, and erythrocyte sedimentation rate) in the diagnosis of TB in pre-school children (< 6 years at diagnosis, n = 45), as compared with two control groups (pneumococcal pneumonia, n = 25; and healthy controls, n = 49). Normal PCT levels were observed at diagnosis of TB in most cases, while C-reactive protein values and leucocyte counts were slightly elevated when compared to healthy controls. All three inflammatory biomarkers were significantly higher in children with pneumococcal pneumonia.

CONCLUSIONS

In our study, PCT was not a useful diagnostic test for TB in young children. In a low-burden TB setting, PCT may be of some value in distinguishing pulmonary TB from pneumococcal pneumonia. What is Known: • Diagnosis of pediatric tuberculosis on clinical evidence is difficult, particularly in infants and small children. • Studies in adults with tuberculosis have mostly reported normal procalcitonin levels at diagnosis. What is New: • In pre-scholars with tuberculosis, erythrocyte sedimentation rate and white blood cell counts were higher than in healthy controls, but procalcitonin was not. • Procalcitonin may be useful in the differential diagnosis of intrathoracic tuberculosis and pneumococcal pneumonia.

Procalcitonin: The marker of pediatric bacterial infection

Timely recognition of systemic bacterial infections in pediatric care setting is the basis for effective treatment and control. This review provides an overview of procalcitonin (PCT) as an early marker for the detection of severe, invasive bacterial infection in children. Almost all articles on biochemical property and clinical studies in PubMed and Scopus databases regarding their use in pediatric infections and the use of PCT as a marker of bacterial infections were examined. Various methods and analyzers are currently available for the evaluation of PCT. Employment of PCT in the identification of neonatal bacterial infection is a complex process in some conditions. Age specific cut-off, underlying syndrome, and maternal antibiotics usage should be considered when PCT is to be applied in neonates. PCT might be false-negative in these conditions. However, if used appropriately, it can lead to a higher specificity than other immunologic markers. Due to its correlation with the severity of infection, PCT can consequently be used as a prognostic indicator especially for sepsis and urinary tract infection. It is, therefore, a practical supplementary means for the identification of bacterial infections in pediatric health settings.

Impact of PCV13 on community-acquired pneumonia by C-reactive protein and procalcitonin levels in children

BACKGROUND

Many countries have observed an early and strong impact of implementation of the 13-valent pneumococcal conjugate vaccine (PCV13) on community-acquired pneumonia (CAP). High levels of C-reactive protein (CRP) and procalcitonin (PCT) are considered biomarkers of bacterial infection (particularly infection due to pneumococcus); therefore, PCV13 implementation should have different effectiveness on CAP depending on the levels of these two biomarkers. To demonstrate this assumption, we analyzed the evolution of number of CAP cases seen in pediatric emergency departments in France after PCV13 implementation (in 2010) by levels of these two biomarkers.

METHODS

From June 2009 to May 2015, 8 pediatric emergency units prospectively enrolled all children (1month to 15years) with radiologically confirmed CAP.

RESULTS

A cohort of 9586 children with CAP was enrolled (median age 3years). CAP with pleural effusion (PE-CAP) and proven pneumococcal pneumonia (PP-CAP) accounted for 5.5% and 2.0% of cases. During the study period, the number of cases of overall CAP decreased by 25.4%, hospitalized CAP by 30.5%, PE-CAP by 63.4%, CAP with CRP level≥100mg/L by 50.9%, CAP with PCT level≥4ng/L by 60.4% and PP-CAP by 86.4%. We found no change in number of cases of CAP with low levels of CRP (<20 or <40mg/L) or PCT (<0.5ng/mL). The number of cases of CAP overall increased (20.0%) in the last year of the study as compared with the preceeding year but not cases with CRP level≥100mg/L and/or PCT level≥4ng/mL.

CONCLUSION

PCV13 implementation has had a strong impact on number of CAP cases with high levels of CRP and/or PCT in children but no impact on that with low levels of these two biomarkers. Five years after PCV13 implementation, a sustained reduction in CAP cases is observed.

New diagnostic biomarker in acute diarrhea due to bacterial infection in children

BACKGROUND AND OBJECTIVES

Diarrhea is a major cause of morbidity and mortality in children, and diarrhea may be due to infection that is bacterial or non-bacterial. Differentiation between diarrhea from a bacterial or non-bacterial infection is not a simple task, and no single method is present to differentiate between these causes of diarrhea.To evaluate the diagnostic accuracy of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and procalcitonin (PCT) in the diagnosis of acute diarrhea due to bacterial infection.

PATIENTS AND METHODS

Case control study of forty children with bacterial infection diarrhea diagnosed by stool culture and CRP, 40 children with acute non-bacterial infection diarrhea and 30 age- and sex-matched healthy controls. Stool cultures, serum CRP, PCT and serum sTREM-1 were measured in all children on admission.

RESULTS

Children with acute bacterial infection diarrhea had a significant increase in the serum sTREM-1 and PCT levels on admission compared to patients with nonbacterial infection diarrhea and controls (26.3667 ± 16.8184 ng/ml vs 7.2267 ± 6.4174 ng/ml vs 6.7367 ± 5.6479 ng/ml and 39.9933 ± 22.5260 ng/ml vs 1.8533 ± 1.7123 vs 0.2840 ± 0.1208 ng/ml, respectively; P < 0.05). sTREM-1 demonstrated significantly higher sensitivity (93.7%) and specificity (94.3%) in the prediction of bacterial infection as a cause of acute diarrhea in children with an area under the receiver operator characteristic (ROC) curve (95% CI) of 0.94 (0.84-0.99) at a cutoff value of 12.4 ng/ml.

CONCLUSIONS

Both serum PCT and sTREM-1 are valuable in the early diagnosis of acute bacterial infection-induced diarrhea in children, and there was markedly higher diagnostic discriminatory power for sTREM-1.

Clinical features and inflammatory markers in pediatric pneumonia: a prospective study

In this prospective, observational study on previously healthy children <18 years, we aimed to study the diagnostic ability of clinical features and inflammatory markers to (i) predict pathologic chest radiography in suspected pneumonia and (ii) differentiate etiology in radiological proven pneumonia. In 394 cases of suspected pneumonia, 265 (67%) had radiographs consistent with pneumonia; 34/265 had proof of bacterial etiology. Of the cases, 86.5% had received pneumococcal conjugate vaccine. In suspected pneumonia, positive chest radiography was significantly associated with increasing C-reactive protein (CRP) values, higher age, and SpO₂ ≤92% in multivariate logistic regression, OR 1.06 (95% CI 1.03 to 1.09), OR 1.09 (95% CI 1.00 to1.18), and OR 2.71 (95% CI 1.42 to 5.18), respectively. In proven pneumonia, bacterial pneumonia was significantly differentiated from viral/atypical pneumonia by increasing CRP values and SpO₂ >92% in multivariate logistic regression, OR 1.09 (95% CI 1.05 to 1.14) and OR 0.23 (95% CI 0.06 to 0.82), respectively. Combining high CRP values (>80 mg/L) and elevated white blood cell (WBC) count provided specificity >85%, positive likelihood ratios >3, but sensitivity <46% for both radiographic proven and bacterial pneumonia.

CONCLUSION

With relatively high specificity and likelihood ratio CRP, WBC count and hypoxemia may be beneficial in ruling in a positive chest radiograph in suspected pneumonia and bacterial etiology in proven pneumonia, but with low sensitivity, the clinical utility is limited. What is Known: • Pneumonia is recommended to be a clinical diagnosis, and neither clinical features nor inflammatory markers can reliably distinguish etiology. • The etiology of pneumonia has changed after routine pneumococcal conjugate vaccine. What is New: • High CRP and WBC counts were associated with infiltrates in children with suspected pneumonia and with bacterial infection in proven pneumonia. • In the post-pneumococcal vaccination era, viral etiology is expected, and in cases of pneumonia with low CRP and WBC counts, a watch-and-wait strategy for antibiotic treatment may be applied.

A three-step diagnosis of pediatric pneumonia at the emergency department using clinical predictors, C-reactive protein, and pneumococcal PCR

Recommendations for the management of community-acquired pneumonia (CAP) advocate that, in the absence of the clinical and laboratory findings typical of bacterial CAP, antibiotics are not required. However, the true value of the clinical and laboratory predictors of pediatric CAP still needs to be assessed. This prospective cohort study in three emergency departments enrolled 142 children with radiological pneumonia. Pneumonia with lung consolidation was the primary endpoint; complicated pneumonia (bacteremia, empyema, or pleural effusion) was the secondary endpoint. We showed that three clinical signs (unilateral hypoventilation, grunting, and absence of wheezing), elevated procalcitonin (PCT), C-reactive protein (CRP), negative nasopharyngeal viral PCR, or positive blood pneumococcal PCR (P-PCR) were significantly associated with both pneumonia with consolidation and complicated pneumonia. Children with negative clinical signs and low CRP values had a low probability of having pneumonia with consolidation (13%) or complicated pneumonia (6%). Associating the three clinical signs, CRP >80 mg/L and a positive P-PCR ruled in the diagnosis of complicated pneumonia with a positive predictive value of 75%.

CONCLUSION

A model incorporating clinical signs and laboratory markers can effectively assess the risk of having pneumonia. Children with negative clinical signs and low CRP are at a low risk of having pneumonia. For children with positive clinical signs and high CRP, a positive blood pneumococcal PCR can more accurately confirm the diagnosis of pneumonia. What is Known: • Distinguishing between bacterial and viral pneumonia in children is challenging. • Reducing the inappropriate use of antibiotics is a priority. What is New: • Children with negative clinical signs and low C-reactive protein (CRP) values have a low probability of having pneumonia. • Children with high CRP values can be tested using a pneumococcal PCR to rule in the diagnosis of pneumonia with a high positive predictive value.

Sensitivity and Specificity of Soluble Triggering Receptor Expressed on Myeloid Cells-1, Midregional Proatrial Natriuretic Peptide and Midregional Proadrenomedullin for Distinguishing Etiology and to Assess Severity in Community-Acquired Pneumonia

Study Design

This study aimed to evaluate the diagnostic accuracy of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), midregional proatrial natriuretic peptide (MR-proANP) and midregional proadrenomedullin (MR-proADM) to distinguish bacterial from viral community-acquired pneumonia (CAP) and to identify severe cases in children hospitalized for radiologically confirmed CAP. Index test results were compared with those derived from routine diagnostic tests, i.e., white blood cell (WBC) counts, neutrophil percentages, and serum C-reactive protein (CRP) and procalcitonin (PCT) levels.

Methods

This prospective, multicenter study was carried out in the most important children’s hospitals (n = 11) in Italy and 433 otherwise healthy children hospitalized for radiologically confirmed CAP were enrolled. Among cases for whom etiology could be determined, CAP was ascribed to bacteria in 235 (54.3%) children and to one or more viruses in 111 (25.6%) children. A total of 312 (72.2%) children had severe disease.

Results

CRP and PCT had the best performances for both bacterial and viral CAP identification. The cut-off values with the highest combined sensitivity and specificity for the identification of bacterial and viral infections using CRP were ≥7.98 mg/L and ≤7.5 mg/L, respectively. When PCT was considered, the cut-off values with the highest combined sensitivity and specificity were ≥0.188 ng/mL for bacterial CAP and ≤0.07 ng/mL for viral CAP. For the identification of severe cases, the best results were obtained with evaluations of PCT and MR-proANP. However, in both cases, the biomarker cut-off with the highest combined sensitivity and specificity (≥0.093 ng/mL for PCT and ≥33.8 pmol/L for proANP) had a relatively good sensitivity (higher than 70%) but a limited specificity (of approximately 55%).

Conclusions

This study indicates that in children with CAP, sTREM-1, MR-proANP, and MR-proADM blood levels have poor abilities to differentiate bacterial from viral diseases or to identify severe cases, highlighting that PCT maintains the main role at this regard.

Improving diagnosis of pneumococcal disease by multiparameter testing and micro/nanotechnologies

The diagnosis and management of pneumococcal disease remains challenging, in particular in children who often are asymptomatic carriers, and in low-income countries with a high morbidity and mortality from febrile illnesses where the broad range of bacterial, viral and parasitic cases are in contrast to limited, diagnostic resources. Integration of multiple markers into a single, rapid test is desirable in such situations. Likewise, the development of multiparameter tests for relevant arrays of pathogens is important to avoid overtreatment of febrile syndromes with antibiotics. Miniaturization of tests through use of micro- and nanotechnologies combines several advantages: miniaturization reduces sample requirements, reduces the use of consumables and reagents leading to a reduction in costs, facilitates parallelization, enables point-of-care use of diagnostic equipment and even reduces the amount of potentially infectious disposables, characteristics that are highly desirable in most healthcare settings. This critical review emphasizes our vision on the importance of multiparametric testing for diagnosing pneumococcal infections in patients with fever and examines recent relevant developments in micro/nanotechnologies to achieve this goal.

Procalcitonin and community-acquired pneumonia (CAP) in children

The role of procalcitonin (PCT) as a biomarker for sepsis in adults is well documented, while its role in infections affecting neonatal children remains controversial. Among these infections, Community-Acquired pneumonia (CAP) has been studied extensively, because it's the second cause of death in children in developing countries, and one of the most frequent causes of hospitalization in industrialized countries. The PubMed database and the Cochrane Library were used to search for the following keywords: CAP, procalcitonin, and children. Thirteen articles were studied to determine the role of PCT in CAP management, specifically its usefulness for distinguishing pneumococcal infections from viral and unknown infections, for predicting severity and the correct antibiotic treatment. This paper focuses on the studies performed to identify the best inflammatory biomarker for CAP management. Although there is an increase in studies confirming the usefulness of PCT in CAP management in children, further studies are needed to have better understanding of its role for pediatric CAP management.

Determining the microbiological cause of a chest infection

Over recent years non-culture techniques such as specific viral and bacterial nucleic acid amplification, serology and antigen detection have considerably developed and been applied within research studies to clinical samples, significantly increasing pathogen detection in pneumonia. There are promising signs of improved diagnostic yields for pneumococcal pneumonia when using molecular techniques to detect pneumococcal gene sequences in blood or by combining serum biomarkers with rapid pneumococcal urinary antigen testing. Pathogens have traditionally been difficult to detect in pneumonia and treatment is usually successful with empiric antibiotics. However, directed antibiotic treatment has significant benefits in terms of antibiotic stewardship and these new technologies make this goal a possibility, though not yet a reality.

Biomarkers for community-acquired pneumonia in the emergency department

Community-acquired pneumonia is one of the most common reasons for emergency department (ED) visits in children and adults. Despite its prevalence, there are many challenges to proper diagnosis and management of pneumonia. There is no accurate and timely etiologic gold standard to differentiate bacterial from viral disease, and there are limitations with precise risk stratification of patients to ensure appropriate site-of-care decisions. Clinical factors obtained by history and physical examination have limited the ability to diagnose pneumonia etiology and severity. Biomarkers offer information about the host response to infection and pathogen activity within the host that can serve to augment clinical features in decision-making. As science and technology progress, novel biomarkers offer great potential in aiding critical decisions for patients with pneumonia. This review summarizes existing knowledge about biomarkers of host response and pathogen activity, in addition to briefly reviewing emerging biomarkers using novel technologies.

Nasopharyngeal microbiota in healthy children and pneumonia patients

Our study is the first to compare the nasopharyngeal microbiota of pediatric pneumonia patients and control children by 454 pyrosequencing. A distinct microbiota was associated with different pneumonia etiologies. Viral pneumonia was associated with a high abundance of the operational taxonomic unit (OTU) corresponding to Moraxella lacunata. Patients with nonviral pneumonia showed high abundances of OTUs of three typical bacterial pathogens, Streptococcus pneumoniae complex, Haemophilus influenzae complex, and Moraxella catarrhalis. Patients classified as having no definitive etiology harbored microbiota particularly enriched in the H. influenzae complex. We did not observe a commensal taxon specifically associated with health. The microbiota of the healthy nasopharynx was more diverse and contained a wider range of less abundant taxa.

Diagnostic and prognostic value of procalcitonin and C-reactive protein in malnourished children

BACKGROUND

Early recognition of bacterial infections is crucial for their proper management, but is particularly difficult in children with severe acute malnutrition (SAM). The objectives of this study were to evaluate the accuracy of C-reactive protein (CRP) and procalcitonin (PCT) for diagnosing bacterial infections and assessing the prognosis of hospitalized children with SAM, and to determine the reliability of CRP and PCT rapid tests suitable for remote settings.

METHODS

From November 2007 to July 2008, we prospectively recruited 311 children aged 6 to 59 months hospitalized with SAM plus a medical complication in Maradi, Niger. Blood, urine, and stool cultures and chest radiography were performed systematically on admission. CRP and PCT were measured by rapid tests and by reference quantitative methods using frozen serum sent to a reference laboratory.

RESULTS

Median CRP and PCT levels were higher in children with bacteremia or pneumonia than in those with no proven bacterial infection (P < .002). However, both markers performed poorly in identifying invasive bacterial infection, with areas under the curve of 0.64 and 0.67 before and after excluding children with malaria, respectively. At a threshold of 40 mg/L, CRP was the best predictor of death (81% sensitivity, 58% specificity). Rapid test results were consistent with those from reference methods.

CONCLUSIONS

CRP and PCT are not sufficiently accurate for diagnosing invasive bacterial infections in this population of hospitalized children with complicated SAM. However, a rapid CRP test could be useful in these settings to identify children most at risk for dying.

Diagnosis of pneumococcal pneumonia: current pitfalls and the way forward

Streptococcus pneumoniae is the most common cause of community-acquired pneumonia. However, it can also asymptomatically colonize the upper respiratory tract. Because of the need to distinguish between S. pneumoniae that is simply colonizing the upper respiratory tract and S. pneumoniae that is causing pneumonia, accurate diagnosis of pneumococcal pneumonia is a challenging issue that still needs to be solved. Sputum Gram stains and culture are the first diagnostic step for identifying pneumococcal pneumonia and provide information on antibiotic susceptibility. However, these conventional methods are relatively slow and insensitive and show limited specificity. In the past decade, new diagnostic tools have been developed, particularly antigen (teichoic acid and capsular polysaccharides) and nucleic acid (ply, lytA, and Spn9802) detection assays. Use of the pneumococcal antigen detection methods along with biomarkers (C-reactive protein and procalcitonin) may enhance the specificity of diagnosis for pneumococcal pneumonia. This article provides an overview of current methods of diagnosing pneumococcal pneumonia and discusses new and future test methods that may provide the way forward for improving its diagnosis.