Procalcitonin in young febrile infants for the detection of serious bacterial infections

Approach to fever in children

BACKGROUND

Fever in children is one of the most common reasons for outpatient visits as well as in-patient evaluation, often causing anxiety among parents and caregivers. Fever can be a standalone feature or be associated with other localising symptoms and signs like rash, lymphadenopathy, or any other organ system involvement with or without a focus of infection. The etiologies of fever vary depending on the clinical setting and epidemiology. India being a tropical country, sees a distinct spectrum of tropical infections. Physicians need to stay updated on the prevalent diseases in their region and the unique factors that may influence the clinical presentations and course of fever in the cohort of children they manage. The challenge lies in balancing the benefit of early treatment for severe diseases versus the harms of unnecessary investigations and treatment for self-resolving illnesses.

OBJECTIVES

This review aims to provide a comprehensive overview of fever in children, covering its etiology, clinical features, and management strategies. This review offers an algorithmic approach to fever tailored to the Indian setting to guide physicians in identifying the disease based on clinical symptoms and signs, ordering essential laboratory investigations, and initiating appropriate management promptly.

CONTENT

The review categorises fever into various segments like fever with localising signs like rash, lymphadenopathy, fever due to infection localised to a particular organ system, and fever without a focus including fever of unknown origin. It delves into the diverse etiological factors contributing to fever in each of these categories, encompassing infectious and non-infectious origins. It gives pointers to identify the etiology from history, examination, and confirm them with judicious use of diagnostic investigations with emphasis on identifying the red flag signs that require immediate attention, especially in vulnerable groups like neonates and young infants.

Performance of Febrile Infant Algorithms by Duration of Fever

OBJECTIVES

To analyze the performance of commonly used blood tests in febrile infants ≤90 days of age to identify patients at low risk for invasive bacterial infection (bacterial pathogen in blood or cerebrospinal fluid) by duration of fever.

METHODS

We conducted a secondary analysis of a prospective single-center registry that includes all consecutive infants ≤90 days of age with fever without a source evaluated at 1 pediatric emergency department between 2008 and 2021. We defined 3 groups based on caregiver-reported hours of fever (<2, 2-12, and ≥12) and analyzed the performance of the biomarkers and Pediatric Emergency Care Applied Research Network, American Academy of Pediatrics, and Step-by-Step clinical decision rules.

RESULTS

We included 2411 infants; 76 (3.0%) were diagnosed with an invasive bacterial infection. The median duration of fever was 4 (interquartile range, 2-12) hours, with 633 (26.3%) patients with fever of <2 hours. The area under the curve was significantly lower in patients with <2 hours for absolute neutrophil count (0.562 vs 0.609 and 0.728) and C-reactive protein (0.568 vs 0.760 and 0.812), but not for procalcitonin (0.749 vs 0.780 and 0.773). Among well-appearing infants older than 21 days and negative urine dipstick with <2 hours of fever, procalcitonin ≥0.14 ng/mL showed a better sensitivity (100% with specificity 53.8%) than that of the combination of biomarkers of Step-by-Step (50.0% and 82.2%), and of the American Academy of Pediatrics and Pediatric Emergency Care Applied Research Network rules (83.3% and 58.3%), respectively.

CONCLUSIONS

The performance of blood biomarkers, except for procalcitonin, in febrile young infants is lower in fever of very short duration, decreasing the accuracy of the clinical decision rules.

Diagnostic test accuracy of procalcitonin and C-reactive protein for predicting invasive and serious bacterial infections in young febrile infants: a systematic review and meta-analysis

BACKGROUND

Febrile infants presenting in the first 90 days of life are at higher risk of invasive and serious bacterial infections than older children. Modern clinical practice guidelines, mostly using procalcitonin as a diagnostic biomarker, can identify infants who are at low risk and therefore suitable for tailored management. C-reactive protein, by comparison, is widely available, but whether C-reactive protein and procalcitonin have similar diagnostic accuracy is unclear. We aimed to compare the test accuracy of procalcitonin and C-reactive protein in the prediction of invasive or serious bacterial infections in febrile infants.

METHODS

For this systematic review and meta-analysis, we searched MEDLINE, EMBASE, Web of Science, and The Cochrane Library for diagnostic test accuracy studies up to June 19, 2023, using MeSH terms "procalcitonin", and "bacterial infection" or "fever" and keywords "invasive bacterial infection*" and "serious bacterial infection*", without language or date restrictions. Studies were selected by independent authors against eligibility criteria. Eligible studies included participants aged 90 days or younger presenting to hospital with a fever (≥38°C) or history of fever within the preceding 48 h. The primary index test was procalcitonin, and the secondary index test was C-reactive protein. Test kits had to be commercially available, and test samples had to be collected upon presentation to hospital. Invasive bacterial infection was defined as the presence of a bacterial pathogen in blood or cerebrospinal fluid, as detected by culture or quantitative PCR; authors' definitions of serious bacterial infection were used. Data were extracted from selected studies, and the detection of invasive or serious bacterial infections was analysed with two models for each biomarker. Diagnostic accuracy was determined against internationally recognised cutoff values (0·5 ng/mL for procalcitonin, 20 mg/L for C-reactive protein) and pooled to calculate partial area under the curve (pAUC) values for each biomarker. Optimum cutoff values were identified for each biomarker. This study is registered with PROSPERO, CRD42022293284.

FINDINGS

Of 734 studies derived from the literature search, 14 studies (n=7755) were included in the meta-analysis. For the detection of invasive bacterial infections, pAUC values were greater for procalcitonin (0·72, 95% CI 0·56-0·79) than C-reactive protein (0·28, 0·17-0·61; p=0·016). Optimal cutoffs for detecting invasive bacterial infections were 0·49 ng/mL for procalcitonin and 13·12 mg/L for C-reactive protein. For the detection of serious bacterial infections, procalcitonin and C-reactive protein had similar pAUC values (0·55, 0·44-0·69 vs 0·54, 0·40-0·61; p=0·92). For serious bacterial infections, the optimal cutoffs for procalcitonin and C-reactive protein were 0·17 ng/mL and 16·18 mg/L, respectively. Heterogeneity was low for studies investigating the test accuracy of procalcitonin in detecting invasive bacterial infection (I2=23·5%), high for studies investigating procalcitonin for serious bacterial infection (I2=75·5%), and moderate for studies investigating C-reactive protein for invasive bacterial infection (I2=49·5%) and serious bacterial infection (I2=28·3%). The absence of a single definition of serious bacterial infection across studies was the greatest source of interstudy variability and potential bias.

INTERPRETATION

Within a large cohort of febrile infants, a procalcitonin cutoff of 0·5 ng/mL had a superior pAUC value to a C-reactive protein cutoff of 20 mg/L for identifying invasive bacterial infections. In settings without access to procalcitonin, C-reactive protein should therefore be used cautiously for the identification of invasive bacterial infections, and a cutoff value below 20 mg/L should be considered. C-reactive protein and procalcitonin showed similar test accuracy for the identification of serious bacterial infection with internationally recognised cutoff values. This might reflect the challenges involved in confirming serious bacterial infection and the absence of a universally accepted definition of serious bacterial infection.

FUNDING

None.

Leukopenia, neutropenia, and procalcitonin levels in young febrile infants with invasive bacterial infections

BACKGROUND AND OBJECTIVE

Serum procalcitonin (PCT) is a highly accurate biomarker for stratifying the risk of invasive bacterial infections (IBIs) in febrile infants ≤60 days old. However, PCT is unavailable in some settings. We explored the association of leukopenia and neutropenia with IBIs in non-critically ill febrile infants ≤60 days old, with and without PCT.

METHODS

We conducted a secondary analysis of a prospective observational cohort consisting of 7407 non-critically ill infants ≤60 days old with temperatures ≥38°C. We focused on the risk of IBIs in patients with leukopenia (white blood cell [WBC] count <5000 cells/μL) or neutropenia (absolute neutrophil count [ANC] <1000 cells/μL), categorized to extremes of lower values, and the impact of PCT on these associations. Multiple logistic regression was used to identify independent predictors of IBIs.

RESULTS

Final analysis included 6865 infants with complete data; 45% (3098) had PCT data available. Of the 6865, a total of 111 (1.6%) had bacteremia without bacterial meningitis, 18 (0.3%) had bacterial meningitis without bacteremia, and 19 (0.3%) had both bacteremia and bacterial meningitis. IBI was present in four of 20 (20%) infants with WBC counts ≤2500 cells/μL and four of 311 (1.3%) with ANC <1000 cells/μL. In multivariable logistic regression analysis not including PCT, a WBC count <2500 cells/μL was significantly associated with IBI (OR 13.48, 95% CI 2.92-45.35). However, no patients with leukopenia or neutropenia and PCT ≤0.5 ng/mL had IBIs.

CONCLUSIONS

Leukopenia ≤2500 cells/μL in febrile infants ≤60 days old is associated with IBIs. However, in the presence of normal PCT levels, no patients with leukopenia had IBIs. While this suggests leukopenia ≤2500 cells/μL is a risk factor for IBIs in non-critically ill young febrile infants only when PCT is unavailable or elevated, the overall low frequency of leukopenia in this cohort warrants caution in interpretation, with future validation required.

Impact on Emergency Department Interventions After Implementing a Guideline Based on the Pediatric Emergency Care Applied Research Network Prediction Rule for Identifying Low-Risk Febrile Infants 29 to 60 Days Old

BACKGROUND

The Pediatric Emergency Care Applied Research Network (PECARN) prediction rule identifies febrile infants at low risk for serious bacterial infection (SBI). However, its impact on avoidable interventions in the emergency department remains unknown.

OBJECTIVE

To study the impact on lumbar puncture (LP) performance, empiric antibiotic use, and admissions after implementing a febrile infant clinical practice guideline for infants aged 29 to 60 days based on the PECARN prediction rule in the pediatric emergency department.

METHODS

This single center preintervention to postintervention study included infants 29 to 60 days old who presented with a chief complaint of fever from November 2018 to November 2021 and were assessed for SBI via blood culture and either urinalysis or urine culture. A new clinical practice guideline based on the PECARN prediction rule was implemented on December 2019. Lumbar puncture attempts, antibiotic administration, and admissions were compared preimplementation and postimplementation and in subgroups of low- and high-risk patients.

RESULTS

Of 1597 (PRE: 785, POST: 812) infants presenting with fever, 1032 (PRE: 500, POST: 532) met inclusion criteria. Adoption of guideline recommendations (measured as procalcitonin order rate) was 89.7% in eligible infants postimplementation. Overall, there was a significant decrease in LPs (PRE: 30.6%, POST: 22.6%, P < 0.05) and no significant change in antibiotics or admissions. Among low-risk infants, there was a significant reduction in LPs (PRE: 17.2%, POST: 4.4%, P < 0.05) and antibiotics (PRE: 14.5%, POST: 4.1%; P < 0.05). There was no change in missed SBI (PRE: 3, POST: 2, P = 0.65). No cases of missed meningitis preimplementation or postimplementation were observed.

CONCLUSIONS

After implementation of a guideline based on the PECARN prediction rule, we observed a reduction of LPs and antibiotics in low-risk infants. Overall, a decrease in LPs was observed, whereas antibiotic use and admissions remained unchanged.

Predictors of bacteremia in febrile infants under 3 months old in the pediatric emergency department

INTRODUCTION

Fever may serve as the primary indicator of underlying infection in children admitted to the pediatric emergency department (PED), especially in high-risk young infants. This study aimed to identify early clinical factors that could help predict bacteremia in young febrile infants.

METHODS

The study included infants under 90 days of age who were admitted to the PED due to fever. Patients were divided into two groups based on the presence or absence of bacteremia and further divided into three age groups: (1) less than 30 days, (2) 30 to 59 days, and (3) 60 to 90 days. Several clinical and laboratory variables were analyzed, and logistic regression and receiver operating characteristic (ROC) analyses were used to identify potential risk factors associated with bacteremia in young febrile infants.

RESULTS

A total of 498 febrile infants were included, of whom 6.4% were diagnosed with bacteremia. The bacteremia group had a higher body temperature (BT) at triage, especially in neonates, higher pulse rates at triage, longer fever subsidence time, longer hospital stays, higher neutrophil counts, and higher C-reactive protein (CRP) levels than those of the non-bacteremia group. ROC analysis showed that the best cut-off values for predicting bacteremia in infants with pyrexia were a BT of 38.7 °C, neutrophil count of 57.9%, and CRP concentration of 53.8 mg/L.

CONCLUSIONS

A higher BT at triage, increased total neutrophil count, and elevated CRP levels may be useful for identifying bacteremia in young febrile infants admitted to the PED.

Current Status of Antibiotic Stewardship and the Role of Biomarkers in Antibiotic Stewardship Programs

The importance of antibiotic stewardship is increasingly emphasized in accordance with the increasing incidences of multidrug-resistant organisms and accompanying increases in disease burden. This review describes the obstacles in operating an antibiotic stewardship program (ASP), and whether the use of biomarkers within currently available resources can help. Surveys conducted around the world have shown that major obstacles to ASPs are shortages of time and personnel, lack of appropriate compensation for ASP operation, and lack of guidelines or appropriate manuals. Sufficient investment, such as the provision of full-time equivalent ASP practitioners, and adoption of computerized clinical decision systems are useful measures to improve ASP within an institution. However, these methods are not easy in terms of both time commitments and cost. Some biomarkers, such as C-reactive protein, procalcitonin, and presepsin are promising tools in ASP due to their utility in diagnosis and forecasting the prognosis of sepsis. Recent studies have demonstrated the usefulness of algorithmic approaches based on procalcitonin level to determine the initiation or discontinuation of antibiotics, which would be helpful in decreasing antibiotics use, resulting in more appropriate antibiotics use.

Boston Febrile Infant Algorithm 2.0: Improving Care of the Febrile Infant 1-2 Months of Age

Significant variation exists in the management of febrile infants, particularly those between 1 and 2 months of age. An established algorithm for well-appearing febrile infants 1-2 months of age guided clinical care for three decades in our emergency department. With mounting evidence for procalcitonin (PCT) to detect invasive bacterial infection (IBI), we revised our algorithm intending to decrease lumbar punctures (LPs) and antibiotic administration without increasing hospitalizations, revisits, or missed IBI.

METHODS

The algorithm's risk stratification was revised based on the expert review of evidence regarding test performance of PCT for IBI in febrile infants. With the revision, routine LP and empiric antibiotics were not recommended for low-risk infants. We used quality improvement strategies to disseminate the revised algorithm and reinforce uptake. The primary outcomes were the proportion of infants undergoing lumbar punctures or receiving antibiotics. Admission rates, 72-hour revisits requiring admission, and missed IBI were monitored as balancing measures.

RESULTS

We studied 616 infants including 326 (52.9%), after the implementation of the revised algorithm. LP was performed in 66.2% prerevision and 31.9% postrevision (34.3% absolute reduction, P < 0.001). Antibiotic administration decreased by 26.2% (pre 62.4% to post 36.2%, P < 0.001) and hospitalization rates decreased by 8.1% (P = 0.03). There have been no missed IBIs. Adherence to the pathway led to a sustained reduction in LPs and antibiotic administration for 24 months.

CONCLUSION

A revised pathway with the addition of PCT resulted in a safe, sustained reduction in LPs and reduced antibiotic administration in febrile infants 1-2 months of age.

Role of steroids in conservative treatment of parapharyngeal and retropharyngeal abscess in children

Purpose

To characterize the clinical features and outcomes of pediatric patients with retropharyngeal (RPA) or parapharyngeal abscesses (PPA) managed only with medical treatment and showing the importance of early symptoms and imaging studies in the diagnosis of deep neck space infections (DNIs) in children.

Methods

A retrospective analysis of all patients diagnosed with RPA and PPA between 2007 and 2017 was performed in Hospital Universitario Central de Asturias.

Results

30 children were identified, with 11 RPA and 19 PPA. 23 children (76.7%) were under 5 years old, and all were treated with intravenous amoxicillin/clavulanic acid and corticosteroids. Torticollis and fever were present in all patients. The mean length of hospital stay was 7.5 days. There were no complications associated.

Conclusion

DNIs can be treated in a conservative way, reserving the surgical drainage for cases with a complication associated (airway compromise, lack of response to antibiotic therapy, immunocompromised patients). Treatment with intravenous antibiotics and corticosteroids is a safe option, reducing the duration of symptoms and the length of hospital stay.

Machine Learning Approach to Predicting Absence of Serious Bacterial Infection at PICU Admission

BACKGROUND AND OBJECTIVES

Serious bacterial infection (SBI) is common in the PICU. Antibiotics can mitigate associated morbidity and mortality but have associated adverse effects. Our objective is to develop machine learning models able to identify SBI-negative children and reduce unnecessary antibiotics.

METHODS

We developed models to predict SBI-negative status at PICU admission using vital sign, laboratory, and demographic variables. Children 3-months to 18-years-old admitted to our PICU, between 2011 and 2020, were included if evaluated for infection within 24-hours, stratified by documented antibiotic exposure in the 48-hours prior. Area under the receiver operating characteristic curve (AUROC) was the primary model accuracy measure; secondarily, we calculated the number of SBI-negative children subsequently provided antibiotics in the PICU identified as low-risk by each model.

RESULTS

A total of 15 074 children met inclusion criteria; 4788 (32%) received antibiotics before PICU admission. Of these antibiotic-exposed patients, 2325 of 4788 (49%) had an SBI. Of the 10 286 antibiotic-unexposed patients, 2356 of 10 286 (23%) had an SBI. In antibiotic-exposed children, a radial support vector machine model had the highest AUROC (0.80) for evaluating SBI, identifying 48 of 442 (11%) SBI-negative children provided antibiotics in the PICU who could have been spared a median 3.7 (interquartile range 0.9-9.0) antibiotic-days per patient. In antibiotic-unexposed children, a random forest model performed best, but was less accurate overall (AUROC 0.76), identifying 33 of 469 (7%) SBI-negative children provided antibiotics in the PICU who could have been spared 1.1 (interquartile range 0.9-3.7) antibiotic-days per patient.

CONCLUSIONS

Among children who received antibiotics before PICU admission, machine learning models can identify children at low risk of SBI and potentially reduce antibiotic exposure.

Copeptin Release in Arterial Hypotension and Its Association with Severity of Disease in Critically Ill Children

Low copeptin levels may indicate inadequate arginine-vasopressin release promoting arterial hypotension, whereas high copeptin concentrations may reflect disease severity. This single-center prospective non-randomized clinical trial analyzed the course of blood copeptin in critically ill normo- and hypotensive children and its association with disease severity. In 164 patients (median age 0.5 years (interquartile range 0.1, 2.9)), the mean copeptin concentration at baseline was 43.5 pmol/L. Though not significantly different after 61 h (primary outcome, mean individual change: −12%, p = 0.36, paired t-test), we detected 1.47-fold higher copeptin concentrations during arterial hypotension when compared to normotension (mixed-effect ANOVA, p = 0.01). In total, 8 out of 34 patients (23.5%) with low copeptin concentrations <10 pmol/L were hypotensive. Copeptin was highest in the adjusted mixed-effect regression analysis within the first day (+20% at 14 h) and decreased significantly at 108 h (−27%) compared to baseline (p = 0.002). Moreover, we found a significant association with vasopressor-inotrope treatment intensity, infancy (1−12 months) and cardiopulmonary bypass (all p ≤ 0.001). In conclusion, high copeptin values were associated with arterial hypotension and severity of disease in critically ill children. This study does not support the hypothesis that low copeptin values might be indicative of arginine-vasopressin deficiency.

Procalcitonin at 12-36 hours of fever for prediction of invasive bacterial infections in hospitalized febrile neonates

AIM

We aimed to investigate the performance of procalcitonin (PCT) assay between 12 and 36 h after onset of fever (PCT H12-H36) to predict invasive bacterial infection (IBI) (ie, meningitis and/or bacteremia) in febrile neonates.

METHODS

We retrospectively included all febrile neonates hospitalized in the general pediatric department in a teaching hospital from January 2013 to December 2019. PCT assay ≤ 0.6 ng/ml was defined as negative. The primary outcome was to study the performance of PCT H12-H36 to predict IBI.

RESULTS

Out of 385 included neonates, IBI was ascertainable for 357 neonates (92.7%). We found 16 IBI: 3 meningitis and 13 bacteremia. Sensitivity and specificity of PCT H12-H36 in the identification of IBI were, respectively, 100% [95% CI 82.9-100%] and 71.8% [95% CI 66.8-76.6%], with positive and negative predictive values of 14.3% [95% CI 8.4-22.2%] and 100% [95% CI 98.8-100%] respectively. Of the 259 neonates who had a PCT assay within the first 12 h of fever (< H12) and a PCT assay after H12-H36, 8 had IBI. Two of these 8 neonates had a negative < H12 PCT but a positive H12-H36 PCT.

CONCLUSIONS

PCT H12-H36 did not miss any IBI whereas < H12 PCT could missed IBI diagnoses. PCT H12-H36 might be included in clinical decision rule to help physicians to stop early antibiotics in febrile neonates.

Trends in ED Resource Use for Infants 0 to 60 Days Evaluated for Serious Bacterial Infection

OBJECTIVES

We examined trends in resource use for infants undergoing emergency department evaluation for serious bacterial infection, including lumbar puncture (LP), antibiotic administration, hospitalization, and procalcitonin testing, as well as the association between procalcitonin testing and LP, administration of parenteral antibiotics, and hospitalization.

METHODS

We performed a cross-sectional study of infants aged 0 to 60 days who underwent emergency department evaluation for serious bacterial infection with blood and urine cultures from 2010 to 2019 in 27 hospitals in the Pediatric Health Information System. We examined temporal trends in LP, antibiotic administration, hospitalization, and procalcitonin testing from 2010 to 2019. We also estimated multivariable logistic regression models for 2017-2019, adjusted for demographic factors and stratified by age (<28 and 29-60 days), with LP, antibiotic administration, and hospitalization as dependent variables and hospital-level procalcitonin testing as the independent variable.

RESULTS

We studied 106 547 index visits. From 2010 to 2019, rates of LP, antibiotic administration, and hospitalization decreased more for infants aged 29 to 60 days compared with infants aged 0 to 28 days (annual decrease in odds of LP, antibiotics administration, and hospitalization: 0 to 28 days: 5%, 5%, and 3%, respectively; 29-60 days: 15%, 12%, and 7%, respectively). Procalcitonin testing increased significantly each calendar year (odds ratio per calendar year 2.19; 95% confidence interval 1.82-2.62), with the majority (91.1%) performed during 2017-2019. From 2017 to 2019, there was no association between hospital-level procalcitonin testing and any outcome studied (all P values > .05).

CONCLUSIONS

Rates of LP, antibiotic administration, and hospitalization decreased significantly for infants 29 to 60 days during 2010-2019. Although procalcitonin testing increased during 2017-2019, we found no association with hospital-level procalcitonin testing and patterns of resource use.

Novel Biomarkers Differentiating Viral from Bacterial Infection in Febrile Children: Future Perspectives for Management in Clinical Praxis

Differentiating viral from bacterial infections in febrile children is challenging and often leads to an unnecessary use of antibiotics. There is a great need for more accurate diagnostic tools. New molecular methods have improved the particular diagnostics of viral respiratory tract infections, but defining etiology can still be challenging, as certain viruses are frequently detected in asymptomatic children. For the detection of bacterial infections, time consuming cultures with limited sensitivity are still the gold standard. As a response to infection, the immune system elicits a cascade of events, which aims to eliminate the invading pathogen. Recent studies have focused on these host–pathogen interactions to identify pathogen-specific biomarkers (gene expression profiles), or “pathogen signatures”, as potential future diagnostic tools. Other studies have assessed combinations of traditional bacterial and viral biomarkers (C-reactive protein, interleukins, myxovirus resistance protein A, procalcitonin, tumor necrosis factor-related apoptosis-inducing ligand) to establish etiology. In this review we discuss the performance of such novel diagnostics and their potential role in clinical praxis. In conclusion, there are several promising novel biomarkers in the pipeline, but well-designed randomized controlled trials are needed to evaluate the safety of using these novel biomarkers to guide clinical decisions.

Seeking diagnostic and prognostic biomarkers for childhood bacterial pneumonia in sub-Saharan Africa: study protocol for an observational study

INTRODUCTION

Clinically diagnosed pneumonia in children is a leading cause of paediatric hospitalisation and mortality. The aetiology is usually bacterial or viral, but malaria can cause a syndrome indistinguishable from clinical pneumonia. There is no method with high sensitivity to detect a bacterial infection in these patients and, as result, antibiotics are frequently overprescribed. Conversely, unrecognised concomitant bacterial infection in patients with malarial infections occur with omission of antibiotic therapy from patients with bacterial infections. Previously, we identified two combinations of blood proteins with 96% sensitivity and 86% specificity for detecting bacterial disease. The current project aimed to validate and improve these combinations by evaluating additional biomarkers in paediatric patients with clinical pneumonia. Our goal was to describe combinations of a limited number of proteins with high sensitivity and specificity for bacterial infection to be incorporated in future point-of-care tests. Furthermore, we seek to explore signatures to prognosticate clinical pneumonia.

METHODS AND ANALYSIS

Patients (n=900) aged 2-59 months presenting with clinical pneumonia at two Gambian hospitals will be enrolled and classified according to criteria for definitive bacterial aetiology (based on microbiological tests and chest radiographs). We will measure proteins at admission using Luminex-based immunoassays in 90 children with definitive and 160 with probable bacterial aetiology, and 160 children classified according to the prognosis of their disease. Previously identified diagnostic signatures will be assessed through accuracy measures. Moreover, we will seek new diagnostic and prognostic signatures through machine learning methods, including support vector machine, penalised regression and classification trees.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the Gambia Government/Medical Research Council Unit The Gambia Joint Ethics Committee (protocol 1616) and the institutional review board of Boston University Medical Centre (STUDY00000958). Study results will be disseminated to the staff of the study hospitals, in scientific seminars and meetings, and in publications.

TRIAL REGISTRATION NUMBER

H-38462.

Radiographic Pneumonia in Febrile Infants 60 Days and Younger

OBJECTIVE

Few prospective studies have assessed the occurrence of radiographic pneumonia in young febrile infants. We analyzed factors associated with radiographic pneumonias in febrile infants 60 days or younger evaluated in pediatric emergency departments.

STUDY DESIGN

We conducted a planned secondary analysis of a prospective cohort study within 26 emergency departments in a pediatric research network from 2008 to 2013. Febrile (≥38°C) infants 60 days or younger who received chest radiographs were included. Chest radiograph reports were categorized as "no," "possible," or "definite" pneumonia. We compared demographics, Yale Observation Scale scores (>10 implying ill appearance), laboratory markers, blood cultures, and viral testing among groups.

RESULTS

Of 4778 infants, 1724 (36.1%) had chest radiographs performed; 2.7% (n = 46) had definite pneumonias, and 3.9% (n = 67) had possible pneumonias. Patients with definite (13/46 [28.3%]) or possible (15/67 [22.7%]) pneumonias more frequently had Yale Observation Scale score >10 compared with those without pneumonias (210/1611 [13.2%], P = 0.002) in univariable and multivariable analyses. Median white blood cell count (WBC), absolute neutrophil count (ANC), and procalcitonin (PCT) were higher in the definite (WBC, 11.5 [interquartile range, 9.8-15.5]; ANC, 5.0 [3.2-7.6]; PCT, 0.4 [0.2-2.1]) versus no pneumonia (WBC, 10.0 [7.6-13.3]; ANC, 3.4 [2.1-5.4]; PCT, 0.2 [0.2-0.3]; WBC, P = 0.006; ANC, P = 0.002; PCT, P = 0.046) groups, but of unclear clinical significance. There were no cases of bacteremia in the definite pneumonia group. Viral infections were more frequent in groups with definite (25/38 [65.8%]) and possible (28/55 [50.9%]) pneumonias than no pneumonias (534/1185 [45.1%], P = 0.02).

CONCLUSIONS

Radiographic pneumonias were uncommon, often had viruses detected, and were associated with ill appearance, but few other predictors, in febrile infants 60 days or younger.

Hypothermia: A Sign of Sepsis in Young Infants in the Emergency Department?

OBJECTIVES

Diagnosis of sepsis in young infants can be challenging due to the nonspecific signs, which can include hypothermia. Whether the presence of hypothermia in young infants should prompt evaluation for serious infection is unclear. The objectives were to measure the prevalence of serious infection among infants ≤60 days of age with hypothermia in the emergency department (ED) and determine other clinical features of hypothermic infants who have serious infection.

METHODS

This is a retrospective analysis of all infants ≤60 days seen in a children's hospital ED from April 2014 to February 2017. Primary outcome was presence of serious infection, defined as urinary tract infection, bacteremia, meningitis, pneumonia, or herpes virus infection. Hypothermia was defined as a rectal temperature of 36.0°C or less.

RESULTS

Of 4797 infants ≤60 days of age seen in the ED, 116 had hypothermia. The prevalence of serious infection was 2.6% (3/116) in hypothermic infants compared with 15.2% (61/401) in febrile infants (P < 0.01). Hypothermic infants with serious infections were more likely to have a history of prematurity, apnea, poor feeding, lethargy, ill-appearance, and respiratory signs than hypothermic infants without serious infection. All 3 hypothermic infants with serious infection had other concerning features.

CONCLUSIONS

The prevalence of serious infection in hypothermic young infants in the ED is low. Serious infection is unlikely in infants with isolated hypothermia.

Use of Procalcitonin in a Febrile Infant Clinical Pathway and Impact on Infants Aged 29 to 60 Days

OBJECTIVES

Recent evidence suggests that measuring the procalcitonin level may improve identification of low-risk febrile infants who may not need intervention. We describe outcomes after the implementation of a febrile infant clinical pathway recommending measurement of the procalcitonin level for risk stratification.

METHODS

In this single-center retrospective pre-post intervention study of febrile infants aged 29 to 60 days, we used interrupted time series analyses to evaluate outcomes of lumbar puncture (LP), antibiotic administration, hospital admission, and emergency department (ED) length of stay (LOS). A multivariable logistic regression was used to evaluate the odds of LP.

RESULTS

Data were analyzed between January 2017 and December 2019 and included 740 participants. Procalcitonin use increased post-pathway implementation (PI). The proportion of low-risk infants receiving an LP decreased significantly post-PI (P = .001). In the adjusted interrupted time series analysis, there was no immediate level change (shift) post-PI for LP (0.98 [95% confidence interval (CI): 0.49-1.97]), antibiotics (1.17 [95% CI: 0.56-2.43]), admission (1.07 [95% CI: 0.59-1.96]), or ED LOS (1.08 [95% CI: 0.92-1.28]), and there was no slope change post-PI versus pre-PI for any measure (LP: 1.01 [95% CI: 0.94-1.08]; antibiotics: 1.00 [95% CI: 0.93-1.08]; admission: 1.03 [95% CI: 0.97-1.09]; ED LOS: 1.01 [95% CI: 0.99-1.02]). More patients were considered high risk, and fewer had incomplete laboratory test results post-PI (P < .001). There were no missed serious bacterial infections. A normal procalcitonin level significantly decreased the odds of LP (P < .001).

CONCLUSIONS

Clinicians quickly adopted procalcitonin testing. Resource use for low-risk infants decreased; however, there was no change to resource use for the overall population because more infants underwent laboratory evaluation and were classified as high risk post-PI.

Accuracy of PECARN rule for predicting serious bacterial infection in infants with fever without a source

OBJECTIVE

To validate the Febrile Infant Working Group of the Pediatric Emergency Care Applied Research Network (PECARN) clinical prediction rule on an independent cohort of infants with fever without a source (FWS).

DESIGN

Secondary analysis of a prospective registry.

SETTING

Paediatric emergency department of a tertiary teaching hospital.

PATIENTS

Infants ≤60 days old with FWS between 2007 and 2018.

MAIN OUTCOME MEASURES

Prevalence of serious bacterial infection (SBI) and invasive bacterial infection (IBI) in low-risk infants according to the PECARN rule.

RESULTS

Among the 1247 infants included, 256 were diagnosed with an SBI (20.5%), including 38 IBIs (3.1%). Overall, 576 infants (46.0%; 95% CI 43.4% to 49.0%) would have been classified as low risk of SBI by the PECARN rule. Of them, 26 had an SBI (4.5%), including 5 with an IBI (2 (0.8%) diagnosed with bacterial meningitis). Sensitivity and specificity of the PECARN rule were 89.8% (95% CI 85.5% to 93.0%) and 55.5% (95% CI 52.4% to 58.6%) for SBI, with an area under the curve of 0.726 (95% CI 0.702 to 0.750). Its sensitivity to identify SBIs was 88.6% (95% CI 82.0% to 92.9%) among infants with a <6-hour history of fever (54.9% of the infants included).

CONCLUSIONS

The PECARN clinical rule for identifying SBI performed less well in our population than in the original study. This clinical rule should be applied cautiously in young infants with a short history of fever.

Machine Learning To Predict Serious Bacterial Infections in Young Febrile Infants

BACKGROUND

Recent decision rules for the management of febrile infants support the identification of infants at higher risk of serious bacterial infections (SBIs) without the performance of routine lumbar puncture. We derive and validate a model to identify febrile infants ≤60 days of age at low risk for SBIs using supervised machine learning approaches.

METHODS

We conducted a secondary analysis of a multicenter prospective study performed between December 2008 and May 2013 of febrile infants. Our outcome was SBI, (culture-positive urinary tract infection, bacteremia, and/or bacterial meningitis). We developed and validated 4 supervised learning models: logistic regression, random forest, support vector machine, and a single-hidden layer neural network.

RESULTS

A total of 1470 patients were included (1014 >28 days old). One hundred thirty-eight (9.3%) had SBIs (122 urinary tract infections, 20 bacteremia, and 8 meningitis; 11 with concurrent SBIs). Using 4 features (urinalysis, white blood cell count, absolute neutrophil count, and procalcitonin), we demonstrated with the random forest model the highest specificity (74.9, 95% confidence interval: 71.5%-78.2%) with a sensitivity of 98.6% (95% confidence interval: 92.2%-100.0%) in the validation cohort. One patient with bacteremia was misclassified. Among 1240 patients who received a lumbar puncture, this model could have prevented 849 (68.5%) such procedures.

CONCLUSIONS

We derived and internally validated a supervised learning model for the risk-stratification of febrile infants. Although computationally complex, lacking parameter cutoffs, and in need of external validation, this strategy may allow for reductions in unnecessary procedures, hospitalizations, and antibiotics while maintaining excellent sensitivity.

Utility of Procalcitonin as a Biomarker for Sepsis in Children

Sepsis is a complex process defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. It is associated with significant morbidity and mortality rates in both adults and children, and emphasis has been placed on its early recognition and prompt provision of antimicrobials. Owing to limitations of current diagnostic tests (i.e., poor sensitivity and delayed results), significant research has been conducted to identify sepsis biomarkers. Ideally, a biomarker could reliably and rapidly distinguish bacterial infection from other, noninfectious causes of systemic inflammatory illness. In doing so, a sepsis biomarker could be used for earlier identification of sepsis, risk stratification/prognostication, and/or guidance of antibiotic decision-making. In this minireview, we review one of the most common clinically used sepsis biomarkers, procalcitonin, and its roles in sepsis management in these three areas. We highlight key findings in the adult literature but focus the bulk of this review on pediatric sepsis. The challenges and limitations of procalcitonin measurement in sepsis are also discussed.

Reporting and Categorization of Blood Culture Contaminants in Infants and Young Children: A Scoping Review

BACKGROUND

Blood cultures are obtained routinely for infants and young children for the evaluation for serious bacterial infection. Isolation of organisms that represent possible contaminants poses a management challenge. The prevalence of bacteremia reported in this population is potentially biased by inconsistent contaminant categorization reported in the literature. Our aim was to systematically review the definition and reporting of contaminants within the literature regarding infant bacteremia.

METHODS

A search of studies published between 1986 and mid-September 2016 was conducted using Medline/PubMed. Included studies examined children aged 0 to 36 months for whom blood culture was performed as part of a serious bacterial infection evaluation. Studies that involved children in an intensive care unit, prematurely born children, and immunocompromised children or those with an indwelling catheter/device were excluded. Data extracted included contaminant designation methodology, organisms classified as contaminants and pathogens, and contamination and bacteremia rates.

DISCUSSION

Our search yielded 1335 articles, and 69 of them met our inclusion criteria. The methodology used to define contaminants was described in 37 (54%) study reports, and 16 (23%) reported contamination rates, which ranged from 0.5% to 22.8%. Studies defined contaminants according to organism species (n = 22), according to the patient's clinical management (n = 4), and using multifactorial approaches (n = 11). Many common organisms, particularly Gram-positive cocci, were inconsistently categorized as pathogens or contaminants.

CONCLUSIONS

Reporting and categorization of blood culture contamination are inconsistent within the pediatric bacteremia literature, which limits our ability to estimate the prevalence of bacteremia. Although contaminants are characterized most frequently according to organism, we found inconsistency regarding the classification of certain common organisms. A standardized approach to contaminant reporting is needed.

Predictive value of C-reactive protein for the diagnosis of meningitis in febrile infants under 3 months of age in the emergency department

Background

Fever is a common cause of pediatric consultation in the emergency department. However, identifying the source of infection in many febrile infants is challenging because of insufficient presentation of signs and symptoms. Meningitis is a critical cause of fever in infants, and its diagnosis is confirmed invasively by lumbar puncture. This study aimed to evaluate potential laboratory markers for meningitis in febrile infants.

Methods

We retrospectively analyzed infants aged <3 months who visited the emergency department of our hospital between May 2012 and May 2017 because of fever of unknown etiology. Clinical information and laboratory data were evaluated. Receiver operating characteristic (ROC) curves were constructed.

Results

In total, 145 febrile infants aged <3 months who underwent lumbar punctures were evaluated retrospectively. The mean C-reactive protein (CRP) level was significantly higher in the meningitis group than in the non-meningitis group, whereas the mean white blood cell count or absolute neutrophil count (ANC) did not significantly differ between groups. The area under the ROC curve (AUC) for CRP was 0.779 (95% confidence interval [CI], 0.701–0.858). The AUC for the leukocyte count was 0.455 (95% CI, 0.360–0.550) and that for ANC was 0.453 (95% CI, 0.359–0.547). The CRP cut-off value of 10 mg/L was optimal for identifying possible meningitis.

Conclusion

CRP has an intrinsic predictive value for meningitis in febrile infants aged <3 months. Despite its invasiveness, a lumbar puncture may be recommended to diagnose meningitis in young, febrile infants with a CRP level >10 mg/L.

Role of Viral Molecular Panels in Diagnosing the Etiology of Fever in Infants Younger Than 3 Months

As infants with proven viral infection present lower risk of bacterial infection, we evaluated how molecular methods detecting viruses on respiratory secretions could contribute to etiological diagnostic of these febrile episodes. From November 2010 to May 2011, we enrolled all febrile infants <90 days presenting to emergency room. Standard workup included viral rapid antigenic test and viral culture on nasopharyngeal aspirate. Samples negative by rapid testing were tested by molecular methods. From 208 febrile episodes (198 infants) with standard techniques, rate of documented microbiological etiology was 13% at emergency department, 47% during hospitalization, and 64% with viral cultures. Molecular methods increased microbiologically documented etiology rate by 12%, to 76%. Contribution of molecular methods was the highest in infants without clinical source of infection, increasing documentation by 18%, from 50% to 68%. Making viral molecular results rapidly available could help identifying a higher proportion of infants at low risk of serious bacterial infection.

The Negative Predictive Ability of Immature Neutrophils for Bacteremia in Children With Community-Acquired Infections

Background: Bacteremia is a serious condition. We aimed to assess the role of immature neutrophils in peripheral blood smears for prediction of bacteremia in children. Methods: In this cross-sectional study conducted in Salvador, Brazil, blood cultures collected from patients aged ≤18 years were identified. White Blood Cell count (WBC) was performed upon admission. Medical charts were reviewed and cases from the community were included. Results: Out of 833 potentially eligible patients, 263 (31.6%) were excluded. Therefore, the study group comprised 570 patients being blood collected for culture upon admission from all of them and WBC performed upon admission from 566. The median age was 2 years (IQR: 9.4 mo-5 y) and 300 (52.6%) were male. Acute respiratory infection was the most frequent diagnosis (n = 388; 68.1%), being 250 (43.9%) lower (LRTI) and 138 (24.2%) upper respiratory tract infections. Blood culture was positive in 9 (1.6%; 95% CI: 0.8-2.9%) cases, out of which 7 (2.8%) had LRTI. Streptococcus pneumoniae (n = 3), Haemophilus (n = 2), Neisseria meningitidis, viridans streptococci, Streptococcus agalactiae, and Acinetobacter baumanii (n = 1 each) were isolated. The total WBC/mm3 did not differ when children with positive or negative blood culture were compared (12,100 [IQR: 6,950-15,250] vs. 11,000 [IQR: 7,900-14,900]; P = 0.9). However, presence of any immature neutrophil was significantly more frequent among patients with bacteremia in comparison with patients without bacteremia (100% [9/9] vs. 40% [223/557]; P < 0.001). The absolute number of immature neutrophils was significantly lower among children without bacteremia (0 [IQR: 0-259] vs. 325 [IQR: 275-1,106]; P < 0.001). Overall, the area under the ROC curve of the number of immature neutrophils in regard to bacteremia was 0.82 (95% CI: 0.76-0.88; P = 0.001). Among 413 patients with absolute number of immature neutrophils <242/mm³, none had bacteremia; among 153 patients with absolute number of immature neutrophils ≥242/mm³, 9 (5.9%) had bacteremia. Absolute number of immature neutrophils ≥242/mm3 showed: sensitivity 100% (95% CI: 71.7-100%), specificity 74.1% (95% CI: 70.4-77.7%), negative predictive value 100% (95% CI: 99.3-100.0%), and positive predictive value 5.9% (95% CI: 2.9-10.5%). When only children with LRTI were analyzed, the results were similar. Conclusion: The absolute number of immature neutrophils in peripheral blood smear is a potential tool to rule out bacteremia among children with community-acquired infections.

Agreement Between Two Procalcitonin Assays in Hospitalized Children

INTRODUCTION

Agreement between available procalcitonin (PCT) assays is unclear. We sought to compare concordance between Roche and bioMérieux PCT assays using pediatric samples.

METHODS

We evaluated 213 plasma samples from 208 children. We tested each sample on both the Roche and bioMérieux PCT platforms.

RESULTS

At ranges < 2 μg/L, the Roche platform had a mean negative bias of 0.13 μg/L versus the bioMérieux platform. This bias resulted in PCT levels that crossed accepted cut points in 12.7% of patients.

CONCLUSIONS

PCT levels measured on either platform are similar, especially at PCT ranges used for antibiotic decision-making algorithms.

FUNDING

This work was supported by an investigator-initiated research agreement through bioMérieux and by the National Institute of Allergy and Infectious Diseases Childhood Infection Research Program (ChIRP), National Institute of Health and the National Center for Advancing Translational Sciences of the National Institute of Health.

Fever Characteristics and Risk of Serious Bacterial Infection in Febrile Infants

BACKGROUND

Fever is a common complaint in the pediatric emergency department (ED), but the vast majority of children evaluated with fever do not have a serious bacterial infection (SBI). However, in the neonate, a missed SBI can have devastating consequences.

OBJECTIVES

To determine the association between various fever characteristics and the risk of SBI in febrile infants.

METHODS

This is a secondary analysis of the Pediatric Emergency Care Applied Research Network study on febrile infants. Infants with a fever were prospectively enrolled at 26 enrolling EDs between 2008 and 2013. We analyzed association of height of fever, location of where temperature was taken (enrolling ED vs. non-health care location), and duration of fever with SBI.

RESULTS

We included 4821 patients who had at least a blood culture completed. Height of fever was significantly associated with risk of SBI, with an odds ratio of 1.5 (95% confidence interval 1.2-1.8). Duration of fever was not associated with risk of SBI, and a fever taken in the enrolling ED vs. at a non-health care facility was minimally associated with risk of SBI (odds ratio 1.3, 95% confidence interval 1.0-1.5).

CONCLUSION

In all analyses, height of fever was associated with all three major types of SBI in febrile infants. Duration and location of fever were less reliably associated with risk of SBI, but there was a small association of risk of SBI and a fever taken at the enrolling ED vs. at a non-health care location.

The clinical value of plasma hepcidin levels in predicting bacterial infections in febrile children

BACKGROUND

Febrile children are often evaluated for the risk of bacterial infections in the pediatric emergency department (PER). Hepcidin is an acute phase inflammatory protein. In this study, we examined the plasma hepcidin levels in febrile children.

METHODS

This study was conducted at a pediatric emergency department with 123 febrile children. We measured plasma hepcidin levels using an enzyme-linked immunosorbent assay. We further evaluated clinical characteristics and routine blood tests along with the hepcidin levels.

RESULTS

We observed significantly higher plasma hepcidin levels in bacterial enteritis (p = 0.026) and combined with urinary tract infection (p = 0.007). Furthermore, hepcidin levels had a significantly positive correlation with CRP level and length of hospital stay (R = 0.296, p = 0.001 and R = 0.213, p = 0.018). Hepcidin levels greater than 65 ng/mL also more accurately predicted bacterial infections than values below 65 ng/mL (11.7% vs. 2.1%, Odds ratio 8.4, 95% confident interval 1.7-40.9, p = 0.002).

CONCLUSION

This study provides evidence that febrile children with bacterial infection have higher plasma hepcidin levels, and the values correlated with CRP level and length of hospital stay. Therefore, hepcidin values can potentially be adopted as a biomarker for identifying febrile children with bacterial infection, particularly bacterial enteritis and urinary tract infection.

A Clinical Prediction Rule to Identify Febrile Infants 60 Days and Younger at Low Risk for Serious Bacterial Infections

IMPORTANCE

In young febrile infants, serious bacterial infections (SBIs), including urinary tract infections, bacteremia, and meningitis, may lead to dangerous complications. However, lumbar punctures and hospitalizations involve risks and costs. Clinical prediction rules using biomarkers beyond the white blood cell count (WBC) may accurately identify febrile infants at low risk for SBIs.

OBJECTIVE

To derive and validate a prediction rule to identify febrile infants 60 days and younger at low risk for SBIs.

DESIGN, SETTING, AND PARTICIPANTS

Prospective, observational study between March 2011 and May 2013 at 26 emergency departments. Convenience sample of previously healthy febrile infants 60 days and younger who were evaluated for SBIs. Data were analyzed between April 2014 and April 2018.

EXPOSURES

Clinical and laboratory data (blood and urine) including patient demographics, fever height and duration, clinical appearance, WBC, absolute neutrophil count (ANC), serum procalcitonin, and urinalysis. We derived and validated a prediction rule based on these variables using binary recursive partitioning analysis.

MAIN OUTCOMES AND MEASURES

Serious bacterial infection, defined as urinary tract infection, bacteremia, or bacterial meningitis.

RESULTS

We derived the prediction rule on a random sample of 908 infants and validated it on 913 infants (mean age was 36 days, 765 were girls [42%], 781 were white and non-Hispanic [43%], 366 were black [20%], and 535 were Hispanic [29%]). Serious bacterial infections were present in 170 of 1821 infants (9.3%), including 26 (1.4%) with bacteremia, 151 (8.3%) with urinary tract infections, and 10 (0.5%) with bacterial meningitis; 16 (0.9%) had concurrent SBIs. The prediction rule identified infants at low risk of SBI using a negative urinalysis result, an ANC of 4090/µL or less (to convert to ×109 per liter, multiply by 0.001), and serum procalcitonin of 1.71 ng/mL or less. In the validation cohort, the rule sensitivity was 97.7% (95% CI, 91.3-99.6), specificity was 60.0% (95% CI, 56.6-63.3), negative predictive value was 99.6% (95% CI, 98.4-99.9), and negative likelihood ratio was 0.04 (95% CI, 0.01-0.15). One infant with bacteremia and 2 infants with urinary tract infections were misclassified. No patients with bacterial meningitis were missed by the rule. The rule performance was nearly identical when the outcome was restricted to bacteremia and/or bacterial meningitis, missing the same infant with bacteremia.

CONCLUSIONS AND RELEVANCE

We derived and validated an accurate prediction rule to identify febrile infants 60 days and younger at low risk for SBIs using the urinalysis, ANC, and procalcitonin levels. Once further validated on an independent cohort, clinical application of the rule has the potential to decrease unnecessary lumbar punctures, antibiotic administration, and hospitalizations.

The Use of Procalcitonin for Prediction of Pulmonary Bacterial Coinfection in Children With Respiratory Failure Associated With Viral Bronchiolitis

Objectives. Viral bronchiolitis is a frequent cause of pediatric hospitalization and respiratory failure. Procalcitonin (PCT) is a biomarker used to identify serious bacterial infection and can distinguish bacterial and viral infections. Concomitant bacterial pneumonia is not rare in viral bronchiolitis and can lead to a worse clinical course. This study examined the use of PCT in pediatric patients with respiratory failure attributed to viral bronchiolitis to predict concomitant bacterial pneumonia. Methods. This prospective descriptive study evaluated children less than 4 years of age who underwent endotracheal intubation for respiratory failure due to viral bronchiolitis. PCT levels and endotracheal aspirate cultures were obtained at admission. Bacterial pneumonia was defined as at least moderate growth of a single pathogenic organism from endotracheal culture. PCT levels were evaluated in groups with and without concomitant bacterial pneumonia. Results. Thirty-five patients were enrolled between February 2013 and May 2015. All subjects tested positive for at least 1 viral pathogen by nasal wash polymerase chain reaction or enzyme immunoassay. The top viruses obtained were respiratory syncytial virus (n = 15, 42.8%) and rhinovirus (n = 8, 22.9%). The incidence of bacterial pneumonia was 60% (21/35). The PCT median was 0.93 ng/mL (interquartile range = 0.25-6.64) in the bacterial pneumonia group and 1.85 ng/mL (interquartile range = 0.28-7.94) in the nonbacterial pneumonia group. No correlation was found between PCT and bronchiolitis with bacterial coinfection (P = .74). Conclusion. Incidence of bacterial coinfection in patients with respiratory failure and viral bronchiolitis was high. PCT did not predict concomitant bacterial pneumonia in children with viral bronchiolitis.

Association of Procalcitonin Value and Bacterial Coinfections in Pediatric Patients With Viral Lower Respiratory Tract Infections Admitted to the Pediatric Intensive Care Unit

OBJECTIVE

Our primary objective was to determine the utility of procalcitonin (PCT) in detection of bacterial coinfection in children < 5 years admitted to the pediatric intensive care unit with viral lower respiratory tract infection (LRTI).

METHODS

Electronic medical record review of children < 5 years admitted to the pediatric intensive care unit with a viral LRTI who also had at least 1 PCT concentration measurement.

RESULTS

Seventy-five patients were admitted to the intensive care unit and met the inclusion criteria for this investigation. The PCT threshold concentrations of 0.9, 1, 1.4, and 2 ng/mL were found to be statistically significant in determining the presence of a bacterial coinfection. The PCT concentration with the most utility was 1.4 ng/mL with sensitivity, specificity, positive and negative predictive values of 46%, 83%, 68%, and 76%, respectively. For patients with serial PCTs, the second PCT correctly influenced treatment decisions for 11 of 25 patients (44%).

CONCLUSIONS

A PCT value of 1.4 ng/mL determined the presence of a bacterial coinfection primarily owing to the high specificity and negative predictive value. Our data add evidence to the relatively high negative predictive value of PCT concentrations in identifying patients with bacterial coinfection, specifically in the case of viral LRTI. In addition, our preliminary data indicate serial PCT measurements may help further influence correct treatment decisions. Prospective, controlled studies are warranted to validate an appropriate PCT threshold concentration to help in identifying bacterial coinfection as well as to further explore the role of serial PCT values in determining the absence or presence of a bacterial coinfection.

Usefulness of the procalcitonin test in young febrile infants between 1 and 3 months of age

Purpose

To study the usefulness of the procalcitonin (PCT) test in young febrile infants between 1 and 3 months of age.

Methods

We evaluated the medical records of 336 febrile infants between 1 and 3 months of age who visited the Emergency Department or outpatient department of Samsung Changwon Hospital from May 2015 to February 2017, and analyzed the clinical characteristics between infants in the serious bacterial infection (SBI) group and non-SBI group.

Results

Among the 336 infants, 38 (11.3%) had definitive SBI (bacteremia, n=3; meningitis, n=1; urinary tract infection, n=34). The mean PCT (6.4±11.9 ng/mL) and C-reactive protein (CRP) level (3.8±2.6 mg/dL), and the absolute neutrophil count (ANC) (6,984±4,675) for patients in the SBI group were significantly higher than those for patients in the non-SBI group (PCT, 0.3±1.2 ng/mL; CRP, 1.3±1.6 mg/dL; ANC, 4,888±3,661). PCT had lower sensitivity (43.6%), but higher specificity (92.6%) and accuracy (86.9%) than CRP (92.3%, 25.3%, and 33.0%) for identifying SBI. The area under the receiver operating characteristic curves (AUCs) for definitive SBI were PCT 77.0%, CRP 80.8%, WBC 56.8%, ANC 67.8%, and PLT 48.1%. The AUCs for definitive SBI were PCT+CRP 85.4%, PCT+WBC 77.2%, PCT+ANC 81.3%, CRP+WBC 80.1%, and CRP+ANC 81.6%.

Conclusion

Our results suggest that the PCT test or a combination of PCT and CRP tests is a more accurate and specific biomarker to detect and rule out SBIs.

Expanding Existing Antimicrobial Stewardship Programs in Pediatrics: What Comes Next

The prevalence of pediatric antimicrobial stewardship programs (ASPs) is increasing in acute care facilities across the United States. Over the past several years, the evidence base used to inform effective stewardship practices has expanded, and regulatory interest in stewardship programs has increased. Here, we review approaches for established, hospital-based pediatric ASPs to adapt and report standardized metrics, broaden their reach to specialized populations, expand to undertake novel stewardship initiatives, and implement rapid diagnostics to continue their evolution in improving antimicrobial use and patient outcomes.

Increased procalcitonin level is a risk factor for prolonged fever in children with Mycoplasma pneumonia

PURPOSE

Macrolide-resistant Mycoplasma pneumoniae pneumonia (MPP) is characterized by prolonged fever and radiological progression despite macrolide treatment. Few studies have examined serum procalcitonin (PCT) level in children with MPP. We aimed to investigate the association of acute inflammation markers including PCT with clinical parameters in children with MPP.

METHODS

A total of 147 children were recruited. The diagnosis of MPP relied on serial measurement of IgM antibody against mycoplasma and/or polymerase chain reaction. We evaluated the relationships between C-reactive protein (CRP), PCT, and lactate dehydrogenase (LDH) levels and white blood cell (WBC) counts, and clinical severity of the disease. We used multivariate logistic regression analysis to estimate the odds ratio for prolonged fever (>3 days after admission) and hospital stay (> 6 days), comparing quintiles 2-5 of the PCT levels with the lowest quintile.

RESULTS

The serum PCT and CRP levels were higher in children with fever and hospital stay than in those with fever lasting ≤ 3 days after admission and hospital stay ≤ 6 days. CRP level was higher in segmental/lobar pneumonia than in bronchopneumonia. The LDH level and WBC counts were higher in children with fever lasting for >3 days before compared to those with fever lasting for ≤ 3 days. The highest quintile of PCT levels was associated with a significantly higher risk of prolonged fever and/or hospital stay than the lowest quintile.

CONCLUSION

Serum PCT and CRP levels on admission day were associated with persistent fever and longer hospitalization in children with MPP.

The Diagnostic Dilemma of Traumatic Lumbar Puncture: Current Standing of Cerebrospinal Fluid Leukocyte Corrections and Our Experience With Cerebrospinal Fluid Biomarkers

OBJECTIVE

To assess the diagnostic efficiency of cerebrospinal fluid markers of procalcitonin, lactate, and cerebrospinal fluid/serum lactate ratio for detecting bacterial meningitis during traumatic lumbar puncture, and to compare these markers with routinely used uncorrected and corrected leukocyte measurements.

METHODS

Infants aged ≤90 days with traumatic lumbar puncture were prospectively studied. The diagnostic characteristics of cerebrospinal fluid assays of uncorrected and corrected leukocyte count, procalcitonin, lactate, and lactate ratio were described and compared.

RESULTS

Considering the area under the curve (95% CI) analysis and standard cutoff values, the lactate-ratio (0.985 [0.964-0.989] at cutoff 1.2) had the best test indexes for identifying meningitis, followed by lactate (0.964 [0.945-0.984] at cutoff 2.2 mmol/L) and procalcitonin (0.939 [0.891-0.986] at cutoff 0.33 ng/mL) measurement, whereas the corrected total leukocyte count assay (0.906 [0.850-0.962] at cutoff 350 cells/mm³) had diagnostic properties moderately superior to uncorrected total leukocyte count measurement (0.870 [0.798-0.943] at cutoff 430 cells/mm³).

CONCLUSION

Cerebrospinal fluid levels of procalcitonin, lactate, and lactate-ratio are reliable markers to diagnose bacterial meningitis in blood-contaminated cerebrospinal fluid.

Diagnostic Value of PCT and CRP for Detecting Serious Bacterial Infections in Patients With Fever of Unknown Origin: A Systematic Review and Meta-analysis

BACKGROUND

It is vital to recognize the cause of an infection to enable earlier treatment. Studies have shown that procalcitonin (PCT) and C-reactive protein (CRP) have very high sensitivity and specificity for diagnosing serious bacterial infections (SBIs), with PCT performing better than CRP.

METHODS

Multiple databases were searched for relevant studies, and full-text articles involving diagnosis with PCT and CRP were reviewed. All meta-analyses were conducted with Review Manager 5.0. Sensitivity and bias analyses were performed to evaluate the quality of articles. In addition, a funnel plot and Egger test were used to assess possible publication bias.

RESULT

A total of 17 articles met the criteria for inclusion. The concentrations of both PCT and CRP were higher in the SBI group than in the nonbacterial infection group. Sensitivity for differentiating bacterial infections from nonbacterial infections was higher for PCT compared with CRP, whereas there was no significant difference in specificity. The area under the summary receiver operating characteristic curve for PCT was larger than that for CRP.

CONCLUSION

Both PCT and CRP are useful markers and should be used to evaluate SBIs with fever of unknown origin.

Patients with Bacteraemia Discharged from the Department of Emergency Medicine: Distribution of Organisms and Associated Characteristics

Introduction

Although blood cultures are commonly used to investigate febrile patients presenting to an emergency department, treatment decisions usually have to be made before the results are available.

Methods

We performed a retrospective analysis of consecutive patients presenting with community-acquired bacteraemia at the emergency department of Nambour Hospital, Queensland, Australia between 2000 and 2008. We determined their clinical characteristics, the distribution of organisms and also assessed patient characteristics associated with discharge from the emergency department.

Results

A total of 885 patients with 915 presentations of community-acquired bacteraemia were included. While having bacteraemia, 33 patients (3.6%) were discharged from the emergency department. Age, mode of presentation, altered mental state, presence of immunocompromise, presence of respiratory distress, C reactive protein, Charlson score, age score and estimated 10 years survival were significant factors discriminating the admitted from discharged patients. The most commonly found organism in blood cultures of discharged patients was Staphylococcus aureus (27.3%), whereas in admitted patients it was E. coli (27.7%). Methicillin-resistant Staphylococcus aureus accounted for 1.7% of cases of community-acquired bacteraemia.

Conclusions

Emergency physicians only rarely discharge patients with community-acquired bacteraemia using current assessment tools and decision-making rules. However, they tend to discharge younger self-presenting patients with good baseline function.

Management of the Febrile Young Infant: Update for the 21st Century

Infants aged 90 days or younger with fever are frequently evaluated in the pediatric emergency department. Physical examination findings and individual laboratory investigations are not reliable to differentiate benign viral infections from serious bacterial infections in febrile infants. Clinical prediction models were developed more than 25 years ago and have high sensitivity but relatively low specificity to identify bacterial infections in febrile infants. Newer laboratory investigations such as C-reactive protein and procalcitonin have favorable test characteristics compared with traditional laboratory studies such as a white blood cell count. These novel biomarkers have not gained widespread acceptance because of lack of robust prospectively collected data, varying thresholds to define positivity, and differing inclusion criteria across studies. However, C-reactive protein and procalcitonin, when combined with other patient characteristics in the step-by-step approach, have a high sensitivity for detection of serious bacterial infection. The RNA biosignatures are a novel biomarker under investigation for detection of bacterial infection in febrile infants.

Cerebrospinal fluid procalcitonin as a biomarker of bacterial meningitis in neonates

OBJECTIVE

The objective of the study was to study the performance of cerebrospinal fluid (CSF) procalcitonin as a marker for bacterial meningitis in neonates, and to determine its optimal 'cutoff' in CSF that can be called significant for the diagnosis.

STUDY DESIGN

Neonates qualifying for lumbar puncture were prospectively studied. Procalcitonin and established CSF parameters were recorded.

RESULTS

At a cut-off value of 0.33 ng ml^-1, CSF procalcitonin had a sensitivity of 0.92, specificity of 0.87, with positive and negative likelihood ratios of 7.13 and 0.092, respectively. The area under the curve for different CSF parameters was: 0.926 (0.887 to 0.964) (P<0.001) for procalcitonin, 0.965 (0.956 to 0.974) for total leukocyte count, 0.961 (0.94 to 0.983) for neutrophil count, 0.874 (0.825 to 0.923) for protein, 0.946 (0.914 to 0.978) for sugar and 0.92 (0.955 to 0.992) for CSF:serum sugar ratio. The lumbar puncture was traumatic in 36 (21.4%) patients; out of these 15 (41.7%) had bacterial meningitis and 21 (58.3%) had no meningitis. In traumatic lumbar tap group, the median (IQR) CSF procalcitonin in patients with and without meningitis was 1.41 (0.32-3.42) ng/ml and 0.21(0.20-0.31) ng/ml respectively (p<0.05).

CONCLUSIONS

Procalcitonin measurement has diagnostic efficiency similar to the established CSF markers. Routine assessment of procalcitonin in clean non-contaminated CSF may not yield additional information, but it may have clinical utility in situations where diagnosis of meningitis is in dilemma, as in the case of blood contamination of CSF in traumatic lumbar punctures.

The Yale Observation Scale Score and the Risk of Serious Bacterial Infections in Febrile Infants

OBJECTIVES

To assess the performance of the Yale Observation Scale (YOS) score and unstructured clinician suspicion to identify febrile infants ≤60 days of age with and without serious bacterial infections (SBIs).

METHODS

We performed a planned secondary analysis of a prospective cohort of non-critically ill, febrile, full-term infants ≤60 days of age presenting to 1 of 26 participating emergency departments in the Pediatric Emergency Care Applied Research Network. We defined SBIs as urinary tract infections, bacteremia, or bacterial meningitis, with the latter 2 considered invasive bacterial infections. Emergency department clinicians applied the YOS (range: 6-30; normal score: ≤10) and estimated the risk of SBI using unstructured clinician suspicion (<1%, 1%-5%, 6%-10%, 11%-50%, or >50%).

RESULTS

Of the 4591 eligible infants, 444 (9.7%) had SBIs and 97 (2.1%) had invasive bacterial infections. Of the 4058 infants with YOS scores of ≤10, 388 (9.6%) had SBIs (sensitivity: 51/439 [11.6%]; 95% confidence interval [CI]: 8.8%-15.0%; negative predictive value: 3670/4058 [90.4%]; 95% CI: 89.5%-91.3%) and 72 (1.8%) had invasive bacterial infections (sensitivity 23/95 [24.2%], 95% CI: 16.0%-34.1%; negative predictive value: 3983/4055 [98.2%], 95% CI: 97.8%-98.6%). Of the infants with clinician suspicion of <1%, 106 had SBIs (6.4%) and 16 (1.0%) had invasive bacterial infections.

CONCLUSIONS

In this large prospective cohort of febrile infants ≤60 days of age, neither the YOS score nor unstructured clinician suspicion reliably identified those with invasive bacterial infections. More accurate clinical and laboratory predictors are needed to risk stratify febrile infants.

High Sensitivity Determination of TNF-α for Early Diagnosis of Neonatal Infections with a Novel and Reusable Electrochemical Sensor

Early diagnosis is vital for the reduction of mortality caused by neonatal infections. Since TNF-α can be used as a marker for the early diagnosis, the detection of TNF-α with high sensitivity and specificity has great clinical significance. Herein, a highly sensitive and reusable electrochemical sensor was fabricated. Due to the high specificity of aptamers, TNF-α could be accurately detected from five similar cytokines, even from serum samples. In addition, Au nanoparticles (AuNPs) with a high surface area were able to combine a large number of doxorubicin hydrochloride (DOXh), which made the sensor have a high sensitivity. The sensor had a good linear relationship with TNF-α concentration in the range from 1 to 1 × 10⁴ pg/mL and the lowest detection limit is 0.7 pg/mL. More important was that the sensor could be reused 6 times by a crafty use of chain replacement reaction. Meanwhile, the detection time and cost were greatly reduced. Thus, we believe that these advantages of higher specificity and sensitivity, lower cost, and shorter detection time will provide a stronger potential for early diagnosis of neonatal infections in clinical applications.

Etiology and Laboratory Abnormalities in Bacterial Meningitis in Neonates and Young Infants

We conducted a retrospective review of electronic medical records of all cases of bacterial meningitis in neonates and young infants at our institution from 2004 to 2014. Fifty-six cases were identified. The most common causative organism was group B streptococcus, followed by Escherichia coli and then Listeria monocytogenes. Forty-four of the 56 patients in the study had abnormalities of the blood white blood cell (WBC) count. The most common WBC count abnormalities were leukopenia and elevation of the immature to total (I:T) neutrophil ratio. Six patients in the case series lacked cerebrospinal fluid (CSF) pleocytosis. Overall, just 3 of the 56 patients had normal WBC count with differential, CSF WBC count, and urinalysis. Only 1 of the 56 patients was well appearing with all normal lab studies. Our study indicates that bacterial meningitis may occur without CSF pleocytosis but very infrequently occurs with all normal lab studies and well appearance.

[Construction of a diagnostic prediction model of severe bacterial infection in febrile infants under 3 months old]

INTRODUCTION

Fever is a common cause of paediatric admissions in emergency departments. An aetiological diagnosis is difficult to obtain in those less than 3 months of age, as they tend to have a higher rate of serious bacterial infection (SBI). The aim of this study is to find a predictor index of SBI in children under 3 months old with fever of unknown origin.

METHODS

A study was conducted on all children under 3 months of age with fever admitted to hospital, with additional tests being performed according to the clinical protocol. Rochester criteria for identifying febrile infants at low risk for SBI were also analysed. A predictive model for SBI and positive cultures was designed, including the following variables in the maximum model: C-reactive protein (CRP), procalcitonin (PCT), and meeting not less than four of the Rochester criteria.

RESULTS

A total of 702 subjects were included, of which 22.64% had an SBI and 20.65% had positive cultures. Children who had SBI and a positive culture showed higher values of white cells, total neutrophils, CRP and PCT. A statistical significance was observed with less than 4 Rochester criteria, CRP and PCT levels, an SBI (area under the curve [AUC] 0.877), or for positive cultures (AUC 0.888). Using regression analysis a predictive index was calculated for SBI or a positive culture, with a sensitivity of 87.7 and 91%, a specificity of 70.1 and 87.7%, an LR+ of 2.93 and 3.62, and a LR- of 0.17 and 0.10, respectively.

CONCLUSIONS

The predictive models are valid and slightly improve the validity of the Rochester criteria for positive culture in children less than 3 months admitted with fever.

Procalcitonin for infections in the first week after pediatric liver transplantation

Background

Procalcitonin (PCT) has become a commonly used serum inflammatory marker. Our aim was to describe the kinetics and usefulness of serial post-operative PCT measurements to detect bacterial infection in a cohort of children immediately after pediatric liver transplantation (pLT).

Methods

We performed a retrospective chart review of a cohort of pLT recipients with serial serum PCT measurements in the first week following pLT. The presence of infection was determined on clinical and biological parameters. Normal PCT was defined as < 0.5 (ng/ml).

Results

Thirty-nine patients underwent 41 pLT. PCT was measured daily during the first week post pLT. Values first increased following surgery and then decreased, nearing 0.5 ng/ml at day seven. Peak PCT reached a median of 5.61 ng/ml (IQR 3.83-10.8). Seventeen patients were considered to have an infection. There was no significant difference in daily PCT or peak PCT between infected and non infected patients during the first post-operative week. AUC of ROC curve for PCT during first week was never higher than 0.6.

Conclusions

We conclude that serial PCT measurements during the first week after pLT is not useful to identify patients with bacterial infections. Rather, we propose that serum PCT may be useful after the first week post pLT.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2234-y) contains supplementary material, which is available to authorized users.

Management and Outcomes of Previously Healthy, Full-Term, Febrile Infants Ages 7 to 90 Days

BACKGROUND

There is considerable variation in the approach to infants presenting to the emergency department and outpatient clinics with fever without a source. We set out to describe the current clinical practice regarding culture acquisition on febrile young infants and review the outcomes of infants with and without cultures obtained.

METHODS

This study analyzed Kaiser Permanente Northern California's electronic medical record to identify all febrile, full term, previously healthy infants born between July 1, 2010, and June 30, 2013, presenting for care between 7 and 90 days of age.

RESULTS

During this 3-year study, 96 156 full-term infants were born at Kaiser Permanente Northern California. A total of 1380 infants presented for care with a fever with an incidence rate of 14.4 (95% confidence interval: 13.6-15.1) per 1000 full term births. Fifty-nine percent of infants 7 to 28 days old had a full evaluation compared with 25% of infants 29 to 60 days old and 5% of infants 61 to 90 days old. Older infants with lower febrile temperatures presenting to an office setting were less likely to have a culture. In the 30 days after fevers, 1% of infants returned with a urinary tract infection. No infants returned with bacteremia or meningitis.

CONCLUSIONS

Fever in a medical setting occurred in 1.4% of infants in this large cohort. Forty-one percent of febrile infants did not have any cultures including 24% less than 28 days. One percent returned in the following month with a urinary tract infection. There was no delayed identification of bacteremia or meningitis.

Value of Procalcitonin Measurement for Early Evidence of Severe Bacterial Infections in the Pediatric Intensive Care Unit

OBJECTIVES

To determine whether peak blood procalcitonin (PCT) measured within 48 hours of pediatric intensive care unit (PICU) admission can differentiate severe bacterial infections from sterile inflammation and viral infection and identify potential subgroups of PICU patients for whom PCT may not have clinical utility.

STUDY DESIGN

This was a retrospective, observational study of 646 critically ill children who had PCT measured within 48 hours of admission to an urban, academic PICU. Patients were stratified into 6 categories by infection status. We compared test characteristics for peak PCT, C-reactive protein (CRP), white blood cell count (WBC), absolute neutrophil count (ANC), and % immature neutrophils. The area under the receiver operating characteristic curve was determined for each biomarker to discriminate bacterial infection.

RESULTS

The area under the receiver operating characteristic curve was similar for PCT (0.73, 95% CI 0.69, 0.77) and CRP (0.75, 95% CI 0.71, 0.79; P = .36), but both outperformed WBC, ANC, and % immature neutrophils (P < .01 for all pairwise comparisons). The combination of PCT and CRP was no better than either PCT or CRP alone. Diagnostic patterns prone to false-positive and false-negative PCT values were identified.

CONCLUSIONS

Peak blood PCT measured close to PICU admission was not superior to CRP in differentiating severe bacterial infection from viral illness and sterile inflammation; both PCT and CRP outperformed WBC, ANC, and % immature neutrophils. PCT appeared especially prone to inaccuracies in detecting localized bacterial central nervous system infections or bacterial coinfection in acute viral illness causing respiratory failure.

Lack of Accuracy of Biomarkers and Physical Examination to Detect Bacterial Infection in Febrile Infants

OBJECTIVES

The aim of this study was to analyze the usefulness of physical examination, C-reactive protein (CRP), procalcitonin (PCT), white blood cell (WBC) count, and absolute neutrophils counts (ANCs) for the diagnosis of invasive bacterial infections (IBIs) and potentially serious bacterial infections in infants younger than the age of 3 months presenting with fever without source (FWS) to the emergency department (ED).

METHODS

A descriptive retrospective study that includes all infants aged younger than 3 months who presented with FWS to the ED between July 2008 and January 2012. We evaluated diagnostic performance for each test by receiver operating characteristic curve analysis. Sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were also calculated.

RESULTS

Three hundred eighteen patients met the inclusion criteria. Eleven bacteremia (3.5%) and 76 urinary tract infections (23.9%) were diagnosed. To detect IBI, the areas under the curve for the different tests were as follows: PCT, 0.77 (95% confidence interval [CI], 0.57-0.96); CRP, 0.54 (95% CI, 0.36-0.73); ANC, 0.53 (95% CI, 0.34-0.71); and WBC, 0.42 (0.24-0.61). To detect potentially serious bacterial infections, the areas under the curve were as follows: PCT, 0.66 (95% CI, 0.59-0.74); CRP, 0.68 (0.60-0.76); ANC, 0.64 (0.56-0.71); and WBC, 0.66 (0.58-0.72).

CONCLUSIONS

Procalcitonin is better than CRP, WBC, and ANC to confirm or dismiss the presence of an IBI in infants aged younger than 3 months presenting with FWS to the ED. However, it could not identify almost 30% of infants with IBI. Most patients diagnosed with IBI (10 of 11) presented abnormal values in at least one of the analytical parameters and/or physical appearance. Four of 5 patients with IBI and well appearing presented abnormal results in at least one of the analytical parameters. Therefore, the development of tools combining different tests including the new biomarkers could increase the reliability of the tests for the diagnosis of IBI in these patients.