Biomarkers for Serious Bacterial Infections in Febrile Children

Febrile infections in children are a common cause of presentation to the emergency department (ED). While viral infections are usually self-limiting, sometimes bacterial illnesses may lead to sepsis and severe complications. Inflammatory biomarkers such as C reactive protein (CRP) and procalcitonin are usually the first blood exams performed in the ED to differentiate bacterial and viral infections; nowadays, a better understanding of immunochemical pathways has led to the discovery of new and more specific biomarkers that could play a role in the emergency setting. The aim of this narrative review is to provide the most recent evidence on biomarkers and predictor models, combining them for serious bacterial infection (SBI) diagnosis in febrile children. Literature analysis shows that inflammatory response is a complex mechanism in which many biochemical and immunological factors contribute to the host response in SBI. CRP and procalcitonin still represent the most used biomarkers in the pediatric ED for the diagnosis of SBI. Their sensibility and sensitivity increase when combined, and for this reason, it is reasonable to take them both into consideration in the evaluation of febrile children. The potential of machine learning tools, which represent a real novelty in medical practice, in conjunction with routine clinical and biological information, may improve the accuracy of diagnosis and target therapeutic options in SBI. However, studies on this matter are not yet validated in younger populations, making their relevance in pediatric precision medicine still uncertain. More data from further research are needed to improve clinical practice and decision making using these new technologies.

Clinical Timing-Sequence Warning Models for Serious Bacterial Infections in Adults Based on Machine Learning: Retrospective Study

BACKGROUND

Serious bacterial infections (SBIs) are linked to unplanned hospital admissions and a high mortality rate. The early identification of SBIs is crucial in clinical practice.

OBJECTIVE

This study aims to establish and validate clinically applicable models designed to identify SBIs in patients with infective fever.

METHODS

Clinical data from 945 patients with infective fever, encompassing demographic and laboratory indicators, were retrospectively collected from a 2200-bed teaching hospital between January 2013 and December 2020. The data were randomly divided into training and test sets at a ratio of 7:3. Various machine learning (ML) algorithms, including Boruta, Lasso (least absolute shrinkage and selection operator), and recursive feature elimination, were utilized for feature filtering. The selected features were subsequently used to construct models predicting SBIs using logistic regression (LR), random forest (RF), and extreme gradient boosting (XGBoost) with 5-fold cross-validation. Performance metrics, including the receiver operating characteristic (ROC) curve and area under the ROC curve (AUC), accuracy, sensitivity, and other relevant parameters, were used to assess model performance. Considering both model performance and clinical needs, 2 clinical timing-sequence warning models were ultimately confirmed using LR analysis. The corresponding predictive nomograms were then plotted for clinical use. Moreover, a physician, blinded to the study, collected additional data from the same center involving 164 patients during 2021. The nomograms developed in the study were then applied in clinical practice to further validate their clinical utility.

RESULTS

In total, 69.9% (661/945) of the patients developed SBIs. Age, hemoglobin, neutrophil-to-lymphocyte ratio, fibrinogen, and C-reactive protein levels were identified as important features by at least two ML algorithms. Considering the collection sequence of these indicators and clinical demands, 2 timing-sequence models predicting the SBI risk were constructed accordingly: the early admission model (model 1) and the model within 24 hours of admission (model 2). LR demonstrated better stability than RF and XGBoost in both models and performed the best in model 2, with an AUC, accuracy, and sensitivity of 0.780 (95% CI 0.720-841), 0.754 (95% CI 0.698-804), and 0.776 (95% CI 0.711-832), respectively. XGBoost had an advantage over LR in AUC (0.708, 95% CI 0.641-775 vs 0.686, 95% CI 0.617-754), while RF achieved better accuracy (0.729, 95% CI 0.673-780) and sensitivity (0.790, 95% CI 0.728-844) than the other 2 approaches in model 1. Two SBI-risk prediction nomograms were developed for clinical use based on LR, and they exhibited good performance with an accuracy of 0.707 and 0.750 and a sensitivity of 0.729 and 0.927 in clinical application.

CONCLUSIONS

The clinical timing-sequence warning models demonstrated efficacy in predicting SBIs in patients suspected of having infective fever and in clinical application, suggesting good potential in clinical decision-making. Nevertheless, additional prospective and multicenter studies are necessary to further confirm their clinical utility.

The Impact of Respiratory Symptoms on the Risk of Serious Bacterial Infection in Febrile Infants < 60 Days Old

OBJECTIVES

We aimed to evaluate the impact of respiratory symptoms and positive viral testing on the risk of serious bacterial infections (SBIs).

METHODS

A retrospective study was conducted that included infants (0-60 days) presenting with a fever between 2001 and 2022 at a tertiary hospital in northern Israel. Demographic, clinical, and laboratory parameters were collected, and risk factors for SBIs were analyzed.

RESULTS

Data from a total of 3106 infants, including data from blood, urine, and CSF cultures, were obtained in 96.6%, 89%, and 29% of cases, respectively. A fever without respiratory symptoms (fever only) was present in 1312 infants, while 1794 had a fever and respiratory symptoms-427 were positive for a respiratory virus (virus+), 759 tested negative (virus-), and 608 were not tested. The SBI rate was 5.1% vs. 7.5% in the fever-and-respiratory group vs. the fever-only group (p = 0.004, OR = 0.65 (95% CI = 0.49-0.88)) and 2.8% vs. 7% in the virus+ vs. virus- group (p = 0.002, OR = 0.385, (95% CI = 0.203-0.728)). The male gender, an age < 1 month, leukocytosis > 15 × 10⁹/L, or a CRP > 2 mg/dL increased the risk of SBIs. Respiratory symptoms or a confirmed viral infection reduced the risk of SBIs in the presence of the above risk factors.

CONCLUSIONS

Respiratory symptoms and a positive viral test decreased the risk of SBIs. Combining rapid viral testing with clinical variables may identify low-risk infants. Despite the relatively low risk of SBIs in individuals with viral infections, conducting prospective studies remains essential for accurately predicting the occurrence of these potentially life-threatening infections.

Serious Bacterial Infections in Preterm Infants: Should Their Age Be "Corrected"?

Adjusting the chronological age of preterm infants according to their gestational age is a widely accepted practice in the field of neurodevelopment. It has been suggested for the assessment of preterm infants with suspected infection, but has been poorly validated. Correcting for chronological age is especially critical in infants with a chronological age above 3 months, but a corrected age below 3 months due to the differences in assessment protocols. This study assessed the difference in incidence of serious bacterial infection (SBI) according to chronological and corrected age in preterm infants. A retrospective analysis of pediatric emergency department (PED) presentations was conducted for all 448 preterm infants born in between January 2010 and August 2019. Of the 448 preterm infants, 204 (46%) presented at one of 3 PEDs in Jerusalem, Israel, during their first year of life. Overall, 141 (31.4%) presented with fever and were included in the study. The infants were divided into 3 age groups: 1-corrected age >3 months; 2-chronological age >3 months, but corrected age <3 months; 3-chronological and corrected age <3 months. SBI was diagnosed in 2.6%, 16.7%, and 33.3% of the infants in groups 1, 2 and 3, respectively; (p < 0.01, p = 0.17, p < 0.001). The incidence of SBI in the control group of 300 term infants <3 months presenting to the PED due to fever was 15.3%. Preterm infants with a corrected age <3 months are at increased risk for SBI, similarly to term infants <3 months of age. Age correction should thus be considered for preterm infants presenting with fever.

A simple clinical decision rule may help to rule out severe bacterial infection and spare antibiotics in febrile young children

AIM

To assess the performance of a new clinical decision rule (CDR) to identify patients at a low risk of invasive bacterial infection (IBI) among febrile children and its theoretical impact on antibiotic use.

METHODS

Prospective study including consecutive children <5 years of age who presented in one French paediatric emergency department with fever without source between January and December 2016. With the collected data, we constructed a CDR based on a sequential approach based on age, clinical toxic signs, urinalysis and procalcitonin level. We evaluated its diagnostic performances to identify IBI and its potential impact on antibiotic use.

RESULTS

Among the 1061 children (IBI 11/1061, 1.0%), 693 (65.3%) were classified at low or intermediate risk of IBI, with an IBI prevalence of 0%. The sensitivity and specificity of the CDR to predict IBI were 100% and 73.9%. Negative and positive predictive value were 100% and 3.9%, respectively. Using this new CDR, the current antibiotics exposure would theoretically be reduced from 33.6% to 24.1%.

CONCLUSION

The promising interest of this clinical decision rule, using simple and accessible biological and clinical tools, needs to be confirm with an external validation study, which will allow its use in clinical practice.

The evolving relationship between COVID-19 and serious bacterial infection evaluation in febrile neonates

AIM

The COVID-19 omicron variant surge highlighted the evolving impact of COVID-19. Febrile infants <60 days old are high risk for serious bacterial infections (SBI). This study evaluated the rate of SBI based on COVID-19 infection.

METHODS

We conducted a retrospective chart review at an urban, academic paediatric emergency department. The study enrolled infants 60 days old or less with documented fever. The primary outcome was SBI diagnosed by blood, urine, and/or cerebrospinal fluid cultures. We compared the rate of SBI between COVID-19 groups with an omicron variant and 29- to 60-day-old subgroup analyses.

RESULTS

Two hundred and thirty-three (233) infants meet the criteria. The incidence of SBI was 18.7% in the COVID-19 negative and 1.7% in the COVID-19-positive group which is statistically significant (p < 0.001). Omicron subgroup analysis did not achieve statistical significance (p = 0.62) while COVID-19-positive infants 29-60 days old had a statistically significant lower rate of SBI (p = 0.006).

CONCLUSION

The omicron variant surge provided an additional understanding of the impact of COVID-19 on these high-risk infants. These results can lead to decreased invasive testing and exposure to antibiotics as well as examine the utility of viral testing for risk stratification.

A nomogram for predicting the development of serious bacterial infections in febrile term neonates: A single medical center experience in Southern Taiwan

BACKGROUND

Serious bacterial infections (SBIs) could lead to mortality or severe long-term sequelae in neonates and infants aged <3 months. Accordingly, the aim of this study was to develop a quantitative and accurate assessment tool for predicting the risk of SBIs in febrile neonates.

METHODS

This retrospective study enrolled 131 febrile term neonates (aged <30 days) who were hospitalized at Kaohsiung Veterans General Hospital between January 2005 and December 2020. These neonates were classified into SBI and nonbacterial infection (NBI) groups on the basis of microbiological laboratory reports. The clinical characteristics and routine blood tests of both groups at the time of admission were analyzed. Stepwise logistic regression was applied to create and validate the nomogram for SBI prediction.

RESULTS

Among the 131 febrile neonates, 38 and 93 developed SBIs and NBIs, respectively. At the time of admission, ill clinical appearance, serum myelocyte/metamyelocyte presence, C-reactive protein (CRP) > 2.5 mg/dL, and pyuria were associated with an increased risk of SBIs. Accordingly, these four factors were used to develop a nomogram for SBI prediction, which exhibited significantly high performance (area under curve = 0.848, p < 0.001) in predicting SBI risk.

CONCLUSION

We developed a nomogram combining clinical appearance, serum myelocyte/metamyelocyte presence, CRP, and pyuria for predicting SBI risk in febrile neonates. This tool can assist clinicians in making early diagnoses and delivering the appropriate treatment.

Serious bacterial infections in young children with fever without source after discharge from emergency department: A National Health Insurance database cohort study

BACKGROUND

Well-appearing febrile young children discharged from the emergency department (ED) after medical assessment are still at risk for serious bacterial infections (SBI). The incidence of SBI and the effectiveness of laboratory tests in the pneumococcal conjugate vaccine era remain unknown.

METHODS

We conducted a study using Taiwan's National Health Insurance claims data from 2004 to 2014. Children aged 2-24 months discharged from the ED with a diagnosis compatible with fever without source (FWS) were enrolled.

RESULTS

The study identified 431,884 children from the ED with FWS. 13.53% of the children had revisits, 8.62% needed hospitalization and 1.57% developed SBI. Younger children had a higher SBI rate, but a lower revisit rate. The revisit rate was 12.22% for children aged 2-6 months, 13.61% for children aged 7-12 months and 13.77% for children aged 13-24 months (p < 0.0001). The SBI rate was 4.44% for children aged 2-6 months, 1.85% for children aged 2-6 months and 0.96% for children aged 13-24 months (p < 0.0001). Children with hemogram tests, compared to those without, had a higher revisit rate (16.30% vs. 13.15%, p < 0.0001), and a higher SBI rate in the children aged 13-24 months (1.30% vs. 0.92%, p < 0.0001); furthermore, children with urinalysis had a significantly higher revisit rate (14.42% vs. 13.24%, p < 0.0001) and higher SBI rate (2.10% vs. 1.40%, p < 0.0001).

CONCLUSION

Children with FWS aged 2-24 months who were discharged from ED after blood test and urinalysis were still at risk for SBI, especially those aged 2-6 months.

Potential and promising marker for serious bacterial infections in children: Delta neutrophil index

AIM

This study aimed to evaluate the usefulness and accuracy of the delta neutrophil index (DNI), an index expressing the number of immature granulocytes as a proportion of the total, as an inflammatory marker in predicting serious bacterial infections (SBIs).

METHODS

Paediatric patients admitted to our hospital with fever were divided into four groups: SBI, non-SBI, COVID-19 and control group. White blood cell count, absolute neutrophil count, C-reactive protein and the DNI were recorded, and their accuracy in predicting SBI was evaluated.

RESULTS

Mean DNI was 4.96 ± 8.38 in the SBI group (150 patients), 0.67 ± 1.68 in the non-SBI group (397 patients), 0.29 ± 0.99 in the COVID-19 group (112 patients) and 0.14 ± 0.21 in the control group (102 patients). The DNI was significantly higher in the SBI group compared with the non-SBI (P < 0.001); the non-SBI group also had higher levels than the COVID-19 group (P = 0.005). One percent increase in the DNI increased the SBI rate 1.36 times (odds ratio 1.36 (95% confidence interval 1.23-1.49), P < 0.001). Based on the determined cut-off value (>2.5%), the DNI (odds ratio 6.27 (95% confidence interval 3.85-10.21), P < 0.001) significantly predicted SBIs with 90.4% specificity and 47.7% sensitivity.

CONCLUSIONS

SBIs in childrenare associated with an increase in DNI levels. Compared to other biomarkers, the DNI had higher specificity in predicting SBIs. The DNI may also be usefulin differentiating bacterial and non-bacterial infections in individualclinical syndromes. Currently, there is no evidence that serum DNI aids indifferentiating COVID-19 and upper respiratory tract infection.

Paediatric emergency departments should manage young febrile and afebrile infants the same if they have a fever before presenting

Aim

Our aim was to evaluate the risk of bacterial meningitis, bacteremia, and urinary tract infection (UTI) in infants ≤60 days who presented to paediatric emergency departments (PEDs) after having fever at home. We also investigated any differences between infants who were afebrile or febrile on presentation.

Methods

This was a multicenter retrospective study of infants ≤60 days presented to four Swedish PEDs during 2014–2020 with reported fever at home. We used relative risks (RR) to compare the prevalence of UTI, bacteremia, and bacterial meningitis between the infants who were afebrile and the infants who were still febrile when they presented to the PED.

Results

The cohort comprised 1926 infants, and 702 (36%) were afebrile on presentation. The prevalence of UTI in the afebrile and febrile infants was 6.1% [95% confidence interval (CI) 4.5–8.2] versus 14.2% (95% CI 12.3–16.2), corresponding to an RR of 0.43 (95% CI 0.31–0.59). In infants ≤28 days, the RR for meningitis was 1.05 (95% CI 0.18–6.23) for afebrile versus febrile infants. Five times more febrile infants underwent a lumbar puncture.

Conclusion

Infants who were afebrile on presentation underwent fewer lumbar punctures, but they had similar rates of bacterial meningitis to febrile infants. Different management approaches are not justified.

Multi-incident analysis of reviews of serious adverse clinical events in children with serious bacterial infection and/or sepsis in Queensland, Australia between 2012 and 2017

AIM

To report on findings from a multi-incident analysis of reviews of serious paediatric adverse clinical events related to serious bacterial infection and/or sepsis (hereafter referred to as sepsis for brevity) in Queensland, Australia, between 2012 and 2017.

METHODS

The Queensland Paediatric Quality Council reviewed documentation from reviews of serious adverse events occurring in children (<18 years) with a diagnosis of sepsis at Queensland public hospitals between 2012 and 2017, including clinical details, coronial reports, autopsy reports and root cause analysis documents. A multi-incident tool was designed and used by an expert panel to identify patient and facility demographics, contributing factors, and human and system factors associated with paediatric serious adverse events.

RESULTS

There were 28 serious adverse clinical events reported related to paediatric sepsis, characterised by a high proportion of deaths (23) and a predominance of children aged under 4 years. Approximately half of all facilities were classified as rural and remote health services. Contributing factors included difficulty in recognising and responding to the deteriorating patient, inadequate management/treatment, diagnostic error (mainly diagnostic delay) and escalation delay/failure. Major system factors included communication issues, incorrect use of the early warning tool, inadequate coordination of care planning, policy/protocol/guideline failures and workforce problems.

CONCLUSION

Multi-incident analysis is a useful tool for identifying themes that recur in similar events and presents opportunities for system-wide improvement. Common themes and contributing factors were identified which may provide possibilities for earlier identification and intervention in childhood serious bacterial infection and/or sepsis.

Integrating Clinical Signs at Presentation and Clinician's Non-analytical Reasoning in Prediction Models for Serious Bacterial Infection in Febrile Children Presenting to Emergency Department

OBJECTIVE

Development and validation of clinical prediction model (CPM) for serious bacterial infections (SBIs) in children presenting to the emergency department (ED) with febrile illness, based on clinical variables, clinician's "gut feeling," and "sense of reassurance.

MATERIALS AND METHODS

Febrile children presenting to the ED of Children's Clinical University Hospital (CCUH) between April 1, 2017 and December 31, 2018 were enrolled in a prospective observational study. Data on clinical signs and symptoms at presentation, together with clinician's "gut feeling" of something wrong and "sense of reassurance" were collected as candidate variables for CPM. Variable selection for the CPM was performed using stepwise logistic regression (forward, backward, and bidirectional); Akaike information criterion was used to limit the number of parameters and simplify the model. Bootstrapping was applied for internal validation. For external validation, the model was tested in a separate dataset of patients presenting to six regional hospitals between January 1 and March 31, 2019.

RESULTS

The derivation cohort consisted of 517; 54% (n = 279) were boys, and the median age was 58 months. SBI was diagnosed in 26.7% (n = 138). Validation cohort included 188 patients; the median age was 28 months, and 26.6% (n = 50) developed SBI. Two CPMs were created, namely, CPM1 consisting of six clinical variables and CPM2 with four clinical variables plus "gut feeling" and "sense of reassurance." The area under the curve (AUC) for receiver operating characteristics (ROC) curve of CPM1 was 0.744 (95% CI, 0.683-0.805) in the derivation cohort and 0.692 (95% CI, 0.604-0.780) in the validation cohort. AUC for CPM2 was 0.783 (0.727-0.839) and 0.752 (0.674-0.830) in derivation and validation cohorts, respectively. AUC of CPM2 in validation population was significantly higher than that of CPM1 [p = 0.037, 95% CI (-0.129; -0.004)]. A clinical evaluation score was derived from CPM2 to stratify patients in "low risk," "gray area," and "high risk" for SBI.

CONCLUSION

Both CPMs had moderate ability to predict SBI and acceptable performance in the validation cohort. Adding variables "gut feeling" and "sense of reassurance" in CPM2 improved its ability to predict SBI. More validation studies are needed for the assessment of applicability to all febrile patients presenting to ED.

Age- and sex-specific prevalence of serious bacterial infections in febrile infants ≤60 days, in Sweden

AIM

The aim of the study was to describe age- and sex-specific prevalence of serious bacterial infections (SBI: urinary tract infection, bacteraemia, meningitis) among febrile infants ≤60 days in Sweden.

METHODS

This is a retrospective study in 4 Pediatric Emergency Departments from 2014 to 2017, in previously healthy, full-term infants ≤60 days with fever without a source.

RESULTS

Of the 1,701 included infants, 214 (12.6%; 95% CI, 11.1-14.3) had an SBI. Urinary tract infection (UTI) was diagnosed in 196 (11.5%; 95% CI, 10.0-13.1) patients. In the ≤28 and 29-60 days age-groups, meningitis prevalence was 0.9% (95% CI, 0.3-2.0) and 0.3% (95% CI, 0.1-0.8), whereas bacteraemia prevalence was 3.2% (95% CI, 1.9-4.9) and 0.6% (95% CI, 0.2-1.3). The SBI prevalence was higher in boys 16.0% (95% CI, 13.8-18.5) than girls 8.0% (95% CI, 6.2-10.2; p<0.001), due to 2-fold higher UTI risk. The prevalence of meningitis in boys was 0.3% (95% CI, 0.1- 0.9) vs. 0.7% (95% CI, 0.2-1.6) in girls and of bacteraemia 1.8% (95% CI, 1.0-2.8) vs. 1.0% (95% CI, 0.4-2.0), respectively.

CONCLUSIONS

The total SBI prevalence was 12.6%, and UTI represented the vast majority. The prevalence of bacteraemia and meningitis was low, particularly in the 29-60 days age group, without significant difference between boys and girls.

Benign course and clinical features of COVID-19 in hospitalised febrile infants up to 60 days old

Aim

Minimal data exist regarding the severity of COVID‐19 in febrile infants under 60 days old. This multicentre prospective study explored the clinical course and outcomes of this hospitalised patient population, as, to date, the best approach has not been specifically addressed.

Methods

This study focused on the clinical features, laboratory parameters and outcomes of febrile infants up to 60 days old who tested positive for the virus and were hospitalised in Israel from March 2020 to January 2021. The data were extracted from a real‐time prospective surveillance network for COVID‐19 that includes 20 of the country's 26 hospitals.

Results

We identified 75 febrile young infants (60% female) with COVID‐19 at a median age of 28 days (range 8–56 days). Of these, 84% had an unremarkable medical history, 29% had respiratory symptoms, and 96% had a mild illness. The Rochester criteria showed that 44% were considered at high‐risk for serious bacterial infections, and we found that eight infants actually had concomitant bacterial infections. Outcomes were excellent, and no complications or fatalities were reported.

Conclusion

The excellent outcomes of young febrile infants with COVID‐19 closely resembled other respiratory viral aetiologies of fever in this age group, and there were no fatalities.

A Novel Framework for Phenotyping Children With Suspected or Confirmed Infection for Future Biomarker Studies

Background: The limited diagnostic accuracy of biomarkers in children at risk of a serious bacterial infection (SBI) might be due to the imperfect reference standard of SBI. We aimed to evaluate the diagnostic performance of a new classification algorithm for biomarker discovery in children at risk of SBI. Methods: We used data from five previously published, prospective observational biomarker discovery studies, which included patients aged 0- <16 years: the Alder Hey emergency department (n = 1,120), Alder Hey pediatric intensive care unit (n = 355), Erasmus emergency department (n = 1,993), Maasstad emergency department (n = 714) and St. Mary's hospital (n = 200) cohorts. Biomarkers including procalcitonin (PCT) (4 cohorts), neutrophil gelatinase-associated lipocalin-2 (NGAL) (3 cohorts) and resistin (2 cohorts) were compared for their ability to classify patients according to current standards (dichotomous classification of SBI vs. non-SBI), vs. a proposed PERFORM classification algorithm that assign patients to one of eleven categories. These categories were based on clinical phenotype, test outcomes and C-reactive protein level and accounted for the uncertainty of final diagnosis in many febrile children. The success of the biomarkers was measured by the Area under the receiver operating Curves (AUCs) when they were used individually or in combination. Results: Using the new PERFORM classification system, patients with clinically confident bacterial diagnosis ("definite bacterial" category) had significantly higher levels of PCT, NGAL and resistin compared with those with a clinically confident viral diagnosis ("definite viral" category). Patients with diagnostic uncertainty had biomarker concentrations that varied across the spectrum. AUCs were higher for classification of "definite bacterial" vs. "definite viral" following the PERFORM algorithm than using the "SBI" vs. "non-SBI" classification; summary AUC for PCT was 0.77 (95% CI 0.72-0.82) vs. 0.70 (95% CI 0.65-0.75); for NGAL this was 0.80 (95% CI 0.69-0.91) vs. 0.70 (95% CI 0.58-0.81); for resistin this was 0.68 (95% CI 0.61-0.75) vs. 0.64 (0.58-0.69) The three biomarkers combined had summary AUC of 0.83 (0.77-0.89) for "definite bacterial" vs. "definite viral" infections and 0.71 (0.67-0.74) for "SBI" vs. "non-SBI." Conclusion: Biomarkers of bacterial infection were strongly associated with the diagnostic categories using the PERFORM classification system in five independent cohorts. Our proposed algorithm provides a novel framework for phenotyping children with suspected or confirmed infection for future biomarker studies.

Evaluation of the accuracy of immature granulocyte percentage in predicting pediatric serious bacterial infection

INTRODUCTION

Serious bacterial infections (SBI) are major causes of mortality and morbidity in children. The aim of this study was to determine the accuracy of the immature granulocyte (IG) percentage in predicting SBI.

METHODS

Patients admitted to the pediatric emergency department with fever were divided into two groups: with SBI and with non-SBI. White blood cell (WBC) count, absolute neutrophil count (ANC), C-reactive protein (CRP), and the percentage of IG value were recorded, and their accuracy in predicting SBI was evaluated.

RESULTS

Sixty-one (14.3%) patients fell into the SBI group and 367 (85.7%) were with non-SBI. Mean IG percentage among SBI patients was 0.84 ± 1.21 and 0.27 ± 0.20 for with non-SBI patients (P = .001). Based on disease, the highest IG percentage was found in patients diagnosed with sepsis (IG 3.7 ± 3.5%) and with bacterial meningitis (IG 1.6 ± 1.3%). The area under the curve (AUC) of IG percentage to predict SBI was 0.83 with 95% confidence interval (CI) [0.78-0.88]; WBC was 0.76 (95% CI 0.70-0.83); ANC was 0.73 (95% CI 0.67-0.80), and CRP was 0.79 (95% CI 0.73-0.85). When infection markers were compared to the most appropriate cut-off values in predicting SBI, IG percentage showed the highest sensitivity and specificity. When the cut-off value was determined as >0.35 for IG percentage, sensitivity was 75.4% and specificity was 76.6% in predicting SBI.

CONCLUSION

Patients with SBI had a higher IG percentage. Compared to other biomarkers, IG percentage had higher sensitivity and specificity in predicting SBI.

Comparison of Clinical and Epidemiologic Characteristics of Young Febrile Infants with and without Severe Acute Respiratory Syndrome Coronavirus-2 Infection

OBJECTIVE

To determine features that distinguish febrile young infants with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

STUDY DESIGN

Retrospective single-center study included febrile infants <57 days of age evaluated in the emergency department of Cohen Children's Medical Center of Northwell Health, New Hyde Park, New York, from March 1 to April 30 of 2018, 2019, and 2020. Sociodemographic and clinical features were compared between those seen during the 2020 coronavirus disease-2019 pandemic and previous years, as well as between infants with SARS-CoV-2 infection and infants without SARS-CoV-2 infection (SARS-CoV-2 negative or evaluated during 2018 and 2019).

RESULTS

In all, 124 febrile infants <57 days of age were identified; 38 during the 2-month study period in 2018, 33 in 2019, and 53 in 2020. During 2020, fewer febrile infants had a serious bacterial infection or a positive respiratory viral panel than in prior years (6% vs 21% [P = .02]; 15% vs 53% [P < .001], respectively). SARS-CoV-2 was the most frequent pathogen detected in 2020; of 30 infants tested, 20 tested positive. Infants with SARS-CoV-2 were more likely to identify as Hispanic (P = .004), have public insurance or be uninsured (P = .01), exhibited lethargy (P = .02), had feeding difficulties (P = .002), and had lower white blood cell (P = .001), neutrophil (P < .001), and lymphocyte counts (P = .005) than the 81 infants without SARS-CoV-2 infection. None of the infants with SARS-CoV-2 had concurrent serious bacterial infection or detection of another virus. Overall, disease in infants with SARS-CoV-2 was mild.

CONCLUSIONS

During the peak of the pandemic, SARS-CoV-2 was the predominant pathogen among febrile infants. Socioeconomic, historical, and laboratory features differed significantly between infants infected or not infected with SARS-CoV-2. None of the 20 infants with SARS-CoV-2 infection had an identified coviral or serious bacterial infection.

The etiologic, microbiologic, clinical and outcome characteristics of immunocompetent young children <2 years of age hospitalized with acute neutropenia

BACKGROUND

To describe the etiologic, microbiologic, clinical and outcome characteristics of acute neutropenia (absolute neutrophil count, ANC, <1.5 × 10⁹/L) in hospitalized immunocompetent children.

METHODS

Serious bacterial infections (SBI) were defined as culture-positive blood, urine, cerebrospinal fluid, articular fluid or stool infections, alveolar pneumonia, Brucellosis and Rickettsiosis.

RESULTS

431/671 (64.2%) healthy infants and children hospitalized with acute neutropenia were <2 years of age; 176 (40.8%), 167 (38.8%) and 88 (20.4%) patients were aged 0-3, 4-12 and 13-24 months, respectively. There were 19 (4.4%), 53 (12.3%), 140 (32.5%) and 209 (50.8%) patients with ANC count <200, 200-500, 501-1000 and 1001-1500 × 10⁹ cells/L, respectively. Severe neutropenia (<500 × 10⁹/L) was recorded in 72 (16.7%) patients. Fever >38 °C was present in 208/431 (48.3%) patients. Blood cultures were positive in 10 (2.3%), with Brucella melitensis, Staphylococcus aureus and Enterobacter spp. identified in 4, 3 and 2 patients, respectively; 5/10 patients with positive blood cultures were <3 months of age. Overall, 55/431 (12.7%) and 65/431 (15.1%) patients were diagnosed with SBIs and bacterial infections, respectively. Nasal washings-PCR for respiratory viruses was positive in 139/293 (47.4%) patients tested. An infectious etiology (bacterial and/or viral) was diagnosed in 190/431 (44.1%) patients. Three patients were diagnosed with acute lymphocytic leukemia. Resolution of neutropenia was achieved in 111/208 (53.4%) evaluable patients (63%, 50.6% and 48% of patients aged 0-3, 4-12 and >12 months, respectively and 56.8%, 53.5% and 52% of patients with severe, moderate and mild neutropenia, respectively).

CONCLUSION

Acute neutropenia is common in immunocompetent children <2 years of age and is frequently associated with viral infections. We showed a substantial involvement of bacterial infections and particularly SBIs in the etiology of acute neutropenia. After a 1-month follow-up, resolution of neutropenia occurred in half of the patients, without association with age subgroups and with neutropenia severity.

Outcomes of Young Infants with Hypothermia Evaluated in the Emergency Department

OBJECTIVE

To assess the prevalence of serious infections and mortality among infants ≤90 days of age presenting to the emergency department with hypothermia.

STUDY DESIGN

We performed a cross-sectional cohort study of infants ≤90 days presenting to any of 40 EDs in the Pediatric Health Information Systems between January 1, 2009, and December 31, 2018. Infants with an International Classification of Diseases, ninth or tenth edition, admission/discharge diagnosis code of hypothermia were included. We determined the prevalence of serious bacterial infection (urinary tract infection, bacteremia, and/or bacterial meningitis), pneumonia, herpes simplex virus (HSV) infection, and emergency department/hospital mortality.

RESULTS

We included 3565 infants (1633 male [50.9%] and 3225 ≤30 days of age [90.5%]). Most (65.0%) presented in the first week of life. There were 389 infants (10.8%) with a complex chronic condition. The prevalence of serious bacterial infection was 8.0% (n = 284), including 2.4% (n = 87) with urinary tract infection, 5.6% (n = 199) with bacteremia, and 0.3% (n = 11) with bacterial meningitis. There were 7 patients (0.2%) with neonatal HSV and 9 (0.3%) with pneumonia; 0.2% (n = 6) died. The presence of a complex chronic condition was associated with the presence of serious bacterial infection (P < .001) and was present in 3 of 6 patients who died. In a sensitivity analysis including patients with any diagnosis code of hypothermia (n = 8122), 14.9% had serious bacterial infection, 0.6% had HSV, and 3.3% had pneumonia; 2.0% died.

CONCLUSIONS

Of infants with hypothermia ≤90 days of age, 8.3% had serious bacterial infections or HSV. Compared with literature from febrile infants, hypothermia is associated with a high mortality rate. Complex chronic conditions were particularly associated with poor outcomes. Additional research is required to risk stratify young infants with hypothermia.

Enterovirus, parechovirus, adenovirus and herpes virus type 6 viraemia in fever without source

OBJECTIVES

To evaluate the potential associations between fever without a source (FWS) in children and detection of human enterovirus (HEV), human parechovirus (HPeV), adenovirus (AdV) and human herpesvirus type 6 (HHV-6) in the plasma; and to assess whether the detection of viruses in the plasma is associated with a reduced risk of serious bacterial infection (SBI) and antibiotic use.

DESIGN AND SETTING

Between November 2015 and December 2017, this prospective, single-centre, diagnostic study tested the plasma of children <3 years old with FWS. Real-time (reverse-transcription) PCR for HEV, HPeV, AdV and HHV-6 was used in addition to the standardised institutional work-up. A control cohort was also tested for the presence of viruses in their blood.

RESULTS

HEV, HPeV, AdV and HHV-6 were tested for in the plasma of 135 patients of median age 2.4 months old. At least one virus was detected in 47 of 135 (34.8%): HEV in 14.1%, HHV-6 in 11.1%, HPeV in 5.9% and AdV in 5.2%. There was no difference in antibiotic use between patients with or without virus detected, despite a relative risk of 0.2 for an SBI among patients with viraemia. Controls were less frequently viraemic than children with FWS (6.0% vs 34.8%; p<0.001).

CONCLUSIONS

HEV, HPeV, AdV and HHV-6 are frequently detected in the plasma of children with FWS. Antibiotic use was similar between viraemic and non-viraemic patients despite a lower risk of SBI among patients with viraemia. Point-of-care viral PCR testing of plasma might reduce antibiotic use and possibly investigations and admission rates in patients with FWS.

TRIAL REGISTRATION NUMBER

NCT03224026.

Risk of Meningitis in Infants Aged 29 to 90 Days with Urinary Tract Infection: A Systematic Review and Meta-Analysis

OBJECTIVE

To determine the risk of bacterial meningitis in infants aged 29-90 days with evidence of urinary tract infection (UTI).

METHODS

PubMed (MEDLINE), Embase, and the Cochrane Library were systematically searched for studies reporting rates of meningitis in infants aged 29-90 days with abnormal urinalysis or urine culture. Observational studies in infants with evidence of UTI who underwent lumbar puncture (LP) reporting age-specific event rates of bacterial meningitis and sterile cerebrospinal fluid pleocytosis were included. Prevalence estimates for bacterial meningitis in infants with UTI were pooled in a random effects meta-analysis.

RESULTS

Three prospective and 17 retrospective cohort studies were included in the meta-analysis. The pooled prevalence of concomitant bacterial meningitis in infants with UTI was 0.25% (95% CI, 0.09%-0.70%). Rates of sterile pleocytosis ranged from 0% to 29%. Variation in study methods precluded calculation of a pooled estimate for sterile pleocytosis. In most studies, the decision to perform a LP was up to the provider, introducing selection bias into the prevalence estimate.

CONCLUSIONS

The risk of bacterial meningitis in infants aged 29-90 days with evidence of UTI is low. A selective approach to LP in infants identified as low risk for meningitis by other clinical criteria may be indicated.

Validation of Risk Stratification Criteria to Identify Febrile Neonates at Low Risk of Serious Bacterial Infection

Our objective was to evaluate the accuracy of risk stratification criteria for febrile neonates in the emergency department. This was a retrospective study of febrile neonates ≤56 days of age. Patients were low risk for serious bacterial infection (SBI) if all test results were within normal ranges. Three hundred thirty-eight patients were enrolled with a mean age of 32 (±14) days, and 78 (23%) had SBI: 26 (8%) with bacteremia, 48 (14%) with urinary tract infection, 3 (1%) with meningitis, and 11 (3%) with pneumonia. Risk stratification criteria identified 47 (14%) as low risk, 2 of whom had SBI (both with Group B Streptococcus bacteremia). The sensitivity was 97.4% (95% confidence interval = 91.0% to 99.7%), and the negative predictive value was 95.7% (95% confidence interval = 84.8% to 98.9%). The risk stratification criteria have high sensitivity and high negative predictive value for identifying infants at low risk for SBI. Care must be taken to assure reliable follow-up.

Predicting serious bacterial infection in febrile young infants utilizing body temperature

BACKGROUND

Febrile young infants have a high risk of serious infection. Although measuring vital sign parameters can serve as a rapid and effective assessment in these patients, their predictive value for serious bacterial infection (SBI) has not been fully investigated.

METHODS

This retrospective observational study enrolled febrile (>38.0°C) infants aged <90 days at the time of presentation. Data from the emergency room triage database at Tokyo Metropolitan Children's Medical Center for the period 1 November 2011-30 November 2013, were reviewed. Variables included patient age, gender, and vital sign data, including body temperature, pulse rate, oxygen saturation, definitive diagnosis, and disposition.

RESULTS

Two hundred and sixty-nine patients were included, with a mean age of 55 days, and 158 (58.7%) were male. Of the total, 43 patients had an SBI. On logistic regression, body temperature ≥38.5°C (OR, 2.80; 95%CI: 1.37-5.74) was a significant predictor of SBI.

CONCLUSION

High-grade fever was found to be a significant predictor of SBI in febrile young infants.

Inflammatory Cytokine and Chemokine Patterns in Paediatric Patients with Suspected Serious Bacterial Infection

Background and objectives: In children, acute infection is the most common cause of visits to the emergency department. Although most of them are self-limiting, mortality due to severe bacterial infections (SBI) in developed countries is still high. When the risk of serious bacterial infection is too high to ignore, yet too low to justify admission and hospital observation, clinicians try to improve diagnostic accuracy by performing various laboratory tests. The aim of the study was to investigate whether an early inflammatory cytokine and chemokine panel can add information in diagnostics of SBI and assessment of efficacy of early therapies in hospitalized children with fever. Methods: This study included 51 children with febrile infections that were admitted to the emergency department (ED). Clinical examination and microbiological and radiological tests were used as reference standards for the definition of SBI. Study population was categorized into two groups: (1) patients with SBI (n = 21); (2) patients without SBI (n = 30). Inflammatory cytokine and chemokine panels were analyzed from the first routine blood samples at hospital admission and after 24 h. Results: Out of 12 cytokines and chemokines, only Eotaxin and granulocyte colony-stimulating factor (G-CSF) had statistically significant differences between groups at the time of inclusion. Receiver operator characteristic analysis to predict SBI showed an area under the curve (AUC) of 0.679 for G-CSF. Conclusions: Analysis of inflammatory cytokine profiles may provide additional information in early diagnostics of SBI.

Risk of Serious Bacterial Infection in Infants Aged ≤60 Days Presenting to Emergency Departments with a History of Fever Only

OBJECTIVE

To compare the risk of serious bacterial infection between infants aged ≤60 days who are febrile in the emergency department (ED) and those who have only a history of fever and are afebrile on arrival to the ED.

STUDY DESIGN

In this secondary analysis of a multicenter prospective study using data collected between December 2008 and May 2013, we compared the rate of serious bacterial infection (urinary tract infection [UTI], bacteremia, and/or bacterial meningitis) between infants who have a history of fever but are afebrile on arrival to the ED and those with fever documented in the ED (rectal temperature ≥38.0 °C) using relative risk (RR) with 95% CI. Stratified analyses were performed for age (≤28 and 29-60 days) and serious bacterial infection type. Infants born prematurely and those with a clinical focal infection or serious illness were excluded.

RESULTS

A total of 3825 infants (mean age, 35.2 days; 56.9% male) were included. Of the 1233 (32.2%) who were afebrile in the ED, 108 (8.8%) had a serious bacterial infection (UTI, n = 94 [7.6%]; bacteremia, n = 19 [1.5%]; bacterial meningitis, n = 8 [0.6%]). Of the 2592 infants (67.8%) who were febrile in the ED, 331 (12.8%) had a serious bacterial infection (UTI, n = 285 [11.0%]; bacteremia, n = 61 [2.4%]; bacterial meningitis, n = 17 [0.7%]). The RR for serious bacterial infection for afebrile vs febrile infants was 0.68 (95% CI, 0.56-0.84). A lower risk of serious bacterial infection was also seen among afebrile vs febrile infants aged ≤28 days (RR, 0.69; 95% CI, 0.52-0.93) and age 29-60 days (RR, 0.67; 95% CI, 0.50-0.89).

CONCLUSIONS

The prevalence of serious bacterial infection is lower in infants aged ≤60 days with a history of fever compared with those who are febrile on arrival to the ED. The small risk reduction in this group is unlikely to alter decision making.

Risk of Bacterial Coinfections in Febrile Infants 60 Days Old and Younger with Documented Viral Infections

OBJECTIVE

To determine the risk of serious bacterial infections (SBIs) in young febrile infants with and without viral infections.

STUDY DESIGN

Planned secondary analyses of a prospective observational study of febrile infants 60 days of age or younger evaluated at 1 of 26 emergency departments who did not have clinical sepsis or an identifiable site of bacterial infection. We compared patient demographics, clinical, and laboratory findings, and prevalence of SBIs between virus-positive and virus-negative infants.

RESULTS

Of the 4778 enrolled infants, 2945 (61.6%) had viral testing performed, of whom 1200 (48.1%) were virus positive; 44 of the 1200 had SBIs (3.7%; 95% CI, 2.7%-4.9%). Of the 1745 virus-negative infants, 222 had SBIs (12.7%; 95% CI, 11.2%-14.4%). Rates of specific SBIs in the virus-positive group vs the virus-negative group were: UTIs (33 of 1200 [2.8%; 95% CI, 1.9%-3.8%] vs 186 of 1745 [10.7%; 95% CI, 9.2%-12.2%]) and bacteremia (9 of 1199 [0.8%; 95% CI, 0.3%-1.4%] vs 50 of 1743 [2.9%; 95% CI, 2.1%-3.8%]). The rate of bacterial meningitis tended to be lower in the virus-positive group (0.4%) than in the viral-negative group (0.8%); the difference was not statistically significant. Negative viral status (aOR, 3.2; 95% CI, 2.3-4.6), was significantly associated with SBI in multivariable analysis.

CONCLUSIONS

Febrile infants ≤60 days of age with viral infections are at significantly lower, but non-negligible risk for SBIs, including bacteremia and bacterial meningitis.

Invasive bacterial infections in young afebrile infants with a history of fever

OBJECTIVE

To determine the prevalence of invasive bacterial infections (IBI, pathogenic bacteria in blood or cerebrospinal fluid) in infants less than 90 days old with fever without a source related to the presence or absence of fever on arrival to the emergency department (ED).

DESIGN

Prospective registry-based cohort study.

SETTING

Paediatric ED of a tertiary teaching hospital.

PATIENTS

We included infants less than 90 days old with a history of fever evaluated in the ED from 2003 to 2016.

MAIN OUTCOMES AND MEASURES

The prevalence of IBI in patients with a history of fever who were febrile and afebrile on arrival to the ED.

RESULTS

We included 2470 infants: 678 afebrile and 1792 febrile when evaluated in the ED. Fifty-nine (2.4%) were diagnosed with an IBI (bacteraemia 46, meningitis 7 and sepsis 6): 16 in the group of afebrile infants with a history of fever (2.4%, 95% CI 1.4 to 3.8 vs 43 in the febrile group, 2.4%, 95% CI 1.8 to 3.2). Of the 16 afebrile infants with a history of fever diagnosed with an IBI, 14 were well appearing. The rate of non-IBI (pathogenic bacteria in urine or stools) was similar in both groups (15.5% and 16.7%).

CONCLUSIONS

The prevalence of IBI in infants ≤90 days with a history of fever is similar regardless of the presence of fever on the arrival at the ED. The approach to infants with a history of fever who are afebrile in the ED should not differ from that recommended for infants who are febrile in the ED.

Association Between Dehydration and Fever During the First Week of Life

BACKGROUND

Trying to differentiate serious bacterial infection (SBI) from a self-limiting illness in febrile infants seen in the pediatric emergency department (PED) is a significant challenge. The aim of the study was to determine the prevalence of dehydration and its relationship to SBI in febrile full-term newborns under 1 week of age seen in a PED.

METHODS

A retrospective observational study was carried out on all children younger than 8 days of age with fever who presented to a single, tertiary care, PED from January 2009 to April 2014. Dehydration was defined as plasma sodium >150 mmol/L or >10% loss of birth weight. SBI was defined by the presence of a positive culture in the blood, urine, cerebrospinal fluid; osteoarticular infection; bacterial enteritis; or pneumonia. The primary analysis was the proportion of children with dehydration. A secondary analysis compared proportion of infection according to hydration status.

RESULTS

Of the 895 children under 8 days of age who visited the PED, 69 consulted for fever. Seven patients were excluded because they were transferred from another hospital. Sixty-two eligible patients were included in the final analysis. Of these, 17 (27%) were dehydrated according to our definition. Only 2 patients had an SBI while 2 others had a final diagnosis of viral myocarditis and encephalitis, respectively. None of the 4 children with serious infection fulfilled our definition of dehydration, and all had a plasma sodium level lower than 145 mmol/L.

CONCLUSIONS

Dehydration is frequently associated with fever in infants younger than 8 days of age seen in a PED. Early identification of dehydration may be useful in limiting the aggressive intervention in some of these infants.

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.

Fever in Children: Pearls and Pitfalls

Fever in children is a common concern for parents and one of the most frequent presenting complaints in emergency department visits, often involving non-pediatric emergency physicians. Although the incidence of serious infections has decreased after the introduction of conjugate vaccines, fever remains a major cause of laboratory investigation and hospital admissions. Furthermore, antipyretics are the most common medications administered to children. We review the epidemiology and measurement of fever, the meaning of fever and associated clinical signs in children of different ages and under special conditions, including fever in children with cognitive impairment, recurrent fevers, and fever of unknown origin. While the majority of febrile children have mild, self-resolving viral illness, a minority may be at risk of life-threatening infections. Clinical assessment differs markedly from adult patients. Hands-off evaluation is paramount for a correct evaluation of breathing, circulation and level of interaction. Laboratory markers and clinical prediction rules provide limited help in identifying children at risk for serious infections; however, clinical examination, prudent utilization of laboratory tests, and post-discharge guidance (“safety netting”) remain the cornerstone of safe management of febrile children.

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.

Current Evidence on the Evaluation and Management of Fever Without a Source in Infants Aged 0-90 Days: A Review

BACKGROUND

Despite development of risk stratification tools decades ago, the best strategy for evaluation and management of young infants with fever without a clear source remains uncertain.

OBJECTIVE

To describe the variability in current practice and review recently published evidence in three key areas: inflammatory markers were used as a tool for risk stratification, impact of viral testing, and optimal observation time on antibiotics.

METHOD

Articles were identified using PubMed, Scopus, and Cochrane databases and via experts. Abstracts were screened and potential articles underwent full review if they focused on febrile infants 0- 90 days with fever without a source and outcomes for key topics.

RESULTS

Thirty-two articles were included. Recent studies show that variability exists for most aspects of evaluation and management. C reactive protein and procalcitonin (PCT) perform poorly for identification of serious bacterial infections (SBIs). However, PCT has good diagnostic accuracy for detection of invasive bacterial infections (IBIs), such as bacteremia and meningitis. When PCT is combined with urinalysis and clinical appearance in the Step-by-Step method, the sensitivity for detection of IBI is 92% for infants &gt; 21 days of age. Infants with lab-confirmed viral infection were found to have reduced risk for SBI. Blood culture yield for true pathogens was the highest in the first 12-36 hours after incubation.

CONCLUSION

Recent studies suggest viral testing and inflammatory markers (specifically PCT) can help better stratify young febrile infants at risk for IBIs. Infants who are deemed low risk may benefit from shorter observation times and tailored or discontinued antibiotic therapy.

Barriers of vaccinations against serious bacterial infections among Australian Hajj pilgrims

OBJECTIVES

Vaccination against serious bacterial infections is recommended for Hajj pilgrims. Although the uptake of mandatory vaccines among Hajj pilgrims is acceptable, the uptake of other recommended vaccines remains suboptimal. In this study, we have explored the barriers to vaccination against serious bacterial infections among Australian Hajj pilgrims.

METHODS

Travellers aged 18 years and older planning to attend Hajj in the years 2014 and 2015 were surveyed at the immunization clinic of the Children's Hospital at Westmead, Sydney, Australia. A questionnaire-based survey was conducted to explore pilgrims' vaccination histories for their previous visits to Mecca, the reasons for non-receipt of vaccination, and to assess knowledge about the transmission of infections.

RESULTS

A total of 300 participants aged 18-76 (median 41) years completed the survey. Most (233 [77.7%]) were born outside Australia. Overall, 113 (37.7%) had performed pilgrimage in the past; 19 (16.8%) of them reported receiving pneumococcal vaccine and 16 (14.1%) diphtheria, tetanus and pertussis (DTP) vaccine. Lack of awareness about the availability of the vaccines was the main reason for non-receipt of pneumococcal and DTP vaccines (respectively 41.1% and 44.7%). Most pilgrims (266 [88.7%]) believed that travel vaccines are necessary before embarking on a journey; however, some expressed concerns about adverse reactions (156 [52.0%]), cost (114 [38.0%]), and permissibility of the vaccine according to their religion (6 [2.0%]). Respectively, 187 (62.3%), 145 (48.3%) and 86 (28.7%) respondents did not correctly know how meningococcal and pneumococcal diseases and pertussis transmit. Nevertheless, most (256 [85.3%]) indicated that they trust their family doctor for medical information and most (203 [67.7%]) preferred to receive the medical information in English.

CONCLUSION

The uptake of recommended vaccines against serious bacterial infections among Australian Hajj pilgrims is low. Lack of awareness about the availability of vaccines, misperceptions surrounding the safety of vaccines and high cost are key barriers of uptake.

Association of clinical practice guidelines with emergency department management of febrile infants ≤56 days of age

BACKGROUND

Differences among febrile infant institutional clinical practice guidelines (CPGs) may contribute to practice variation and increased healthcare costs.

OBJECTIVE

Determine the association between pediatric emergency department (ED) CPGs and laboratory testing, hospitalization, ceftriaxone use, and costs in febrile infants.

DESIGN

Retrospective cross-sectional study in 2013.

SETTING

Thirty-three hospitals in the Pediatric Health Information System.

PATIENTS

Infants aged ≤56 days with a diagnosis of fever.

EXPOSURES

The presence and content of ED-based febrile infant CPGs assessed by electronic survey.

MEASUREMENTS

Using generalized estimating equations, we evaluated the association between CPG recommendations and rates of urine, blood, cerebrospinal fluid (CSF) testing, hospitalization, and ceftriaxone use at ED discharge in 2 age groups: ≤28 days and 29 to 56 days. We also assessed CPG impact on healthcare costs.

RESULTS

We included 9377 ED visits; 21 of 33 EDs (63.6%) had a CPG. For neonates ≤28 days, CPG recommendations did not vary and were not associated with differences in testing, hospitalization, or costs. Among infants 29 to 56 days, CPG recommendations for CSF testing and ceftriaxone use varied. CSF testing occurred less often at EDs with CPGs recommending limited testing compared to hospitals without CPGs (adjusted odds ratio: 0.5, 95% confidence interval: 0.3-0.8). Ceftriaxone use at ED discharge varied significantly based on CPG recommendations. Costs were higher for admitted and discharged infants 29 to 56 days old at hospitals with CPGs.

CONCLUSIONS

CPG recommendations for febrile infants 29 to 56 days old vary across institutions for CSF testing and ceftriaxone use, correlating with observed practice variation. CPGs were not associated with lower healthcare costs.

RNA transcriptional biosignature analysis for identifying febrile infants with serious bacterial infections in the emergency department: a feasibility study

OBJECTIVES

To develop the infrastructure and demonstrate the feasibility of conducting microarray-based RNA transcriptional profile analyses for the diagnosis of serious bacterial infections in febrile infants 60 days and younger in a multicenter pediatric emergency research network.

METHODS

We designed a prospective multicenter cohort study with the aim of enrolling more than 4000 febrile infants 60 days and younger. To ensure success of conducting complex genomic studies in emergency department (ED) settings, we established an infrastructure within the Pediatric Emergency Care Applied Research Network, including 21 sites, to evaluate RNA transcriptional profiles in young febrile infants. We developed a comprehensive manual of operations and trained site investigators to obtain and process blood samples for RNA extraction and genomic analyses. We created standard operating procedures for blood sample collection, processing, storage, shipping, and analyses. We planned to prospectively identify, enroll, and collect 1 mL blood samples for genomic analyses from eligible patients to identify logistical issues with study procedures. Finally, we planned to batch blood samples and determined RNA quantity and quality at the central microarray laboratory and organized data analysis with the Pediatric Emergency Care Applied Research Network data coordinating center. Below we report on establishment of the infrastructure and the feasibility success in the first year based on the enrollment of a limited number of patients.

RESULTS

We successfully established the infrastructure at 21 EDs. Over the first 5 months we enrolled 79% (74 of 94) of eligible febrile infants. We were able to obtain and ship 1 mL of blood from 74% (55 of 74) of enrolled participants, with at least 1 sample per participating ED. The 55 samples were shipped and evaluated at the microarray laboratory, and 95% (52 of 55) of blood samples were of adequate quality and contained sufficient RNA for expression analysis.

CONCLUSIONS

It is possible to create a robust infrastructure to conduct genomic studies in young febrile infants in the context of a multicenter pediatric ED research setting. The sufficient quantity and high quality of RNA obtained suggests that whole blood transcriptional profile analysis for the diagnostic evaluation of young febrile infants can be successfully performed in this setting.

Diagnosis and management of bacteremic urinary tract infection in infants

OBJECTIVES

To report the prevalence of bacteremia by age in a sample of infants<1 year of age with urinary tract infections (UTIs), to compare characteristics of infants with UTIs with and without bacteremia, and to describe treatment courses and 30-day outcomes in infants with UTIs with and without bacteremia.

METHODS

We used a retrospective cross-sectional design to determine the prevalence of bacteremia in infants with UTIs at our institution. A double cohort design matching for age and gender was used to compare clinical characteristics and outcomes between infants with bacteremic versus nonbacteremic UTIs.

RESULTS

We identified 1379 UTIs, with blood cultures obtained in 52% of cases. The prevalence of bacteremia was 4.1% (95% confidence interval 3.1%-5.3%) for all UTIs and 8% (95% confidence interval 6.1%-10.2%) for UTIs in which blood culture was obtained. Fifty-five infants with bacteremic UTIs were compared with 110 infants with nonbacteremic UTIs. Except for minor differences in the urinalysis and serum band count, there were no significant differences in clinical presentation between the 2 groups. Bacteremic infants received longer parenteral treatment courses than nonbacteremic infants (mean 6.7 vs 2.4 days, P<.001). Treatment courses in the bacteremic group were variable and predicted by age but not severity of illness. No bacteremic infant had recurrent UTI or bacteremia with the same organism within 30 days of discharge.

CONCLUSIONS

Treatment was variable but outcomes were excellent in infants with bacteremic UTIs.

Variation in care of the febrile young infant <90 days in US pediatric emergency departments

BACKGROUND AND OBJECTIVES

Variation in patient care or outcomes may indicate an opportunity to improve quality of care. We evaluated the variation in testing, treatment, hospitalization rates, and outcomes of febrile young infants in US pediatric emergency departments (EDs).

METHODS

Retrospective cohort study of infants <90 days of age with a diagnosis code of fever who were evaluated in 1 of 37 pediatric EDs between July 1, 2011 and June 30, 2013. We assessed patient- and hospital-level variation in testing, treatment, and disposition for patients in 3 distinct age groups: ≤28, 29 to 56, and 57 to 89 days. We also compared interhospital variation for 3-day revisits and revisits resulting in hospitalization.

RESULTS

We identified 35,070 ED visits that met inclusion criteria. The proportion of patients who underwent comprehensive evaluation, defined as urine, serum, and cerebrospinal fluid testing, decreased with increasing patient age: 72.0% (95% confidence interval [CI], 71.0-73.0) of neonates ≤28 days, 49.0% (95% CI, 48.2-49.8) of infants 29 to 56 days, and 13.1% (95% CI, 12.5-13.6) of infants 57 to 89 days. Significant interhospital variation was demonstrated in testing, treatment, and hospitalization rates overall and across all 3 age groups, with little interhospital variation in outcomes. Hospitalization rate in the overall cohort did not correlate with 3-day revisits (R(2) = 0.10, P = .06) or revisits resulting in hospitalization (R(2) = 0.08, P = .09).

CONCLUSIONS

Substantial patient- and hospital-level variation was observed in the ED management of the febrile young infant, without concomitant differences in outcomes. Strategies to understand and address the modifiable sources of variation are needed.

Infants 1-90 days old hospitalized with human rhinovirus infection

BACKGROUND

Human rhinovirus (HRV) is a common cause of respiratory illness in children. The impact of HRV infection on 1- to 90-day-old infants is unclear. We hypothesized that HRV infection would be clinically similar to respiratory syncytial virus (RSV) infection in the hospitalized infants.

METHODS

We conducted a retrospective study of hospitalized infants, who were 1-90 days old, with HRV or RSV within the Southern California Kaiser Permanente network over a 1-year period (August 2010 to October 2011).

RESULTS

We identified 245 hospitalized infants who underwent respiratory virus testing. HRV was found in 52 infants (21%) compared to 79 infants (32%) with RSV (P = 0.008). Infants with HRV infection experienced longer hospital stays compared to those with RSV (median length of stay 4 days vs. 3 days, P = 0.009) and had fewer short hospital stays ≤3 days (P = 0.029). There was a trend in infants with HRV infection to be younger (P = 0.071) and have more fevers (P = 0.052).

CONCLUSIONS

Recent advances in diagnostics allow for identification of a broad range of viral pathogens in infants. Compared to RSV, HRV was associated with longer hospital stays. Additional studies and improved, more specific testing, methods are needed to further define the effects of HRV infection in infants 1-90 days old.

Diagnostic markers of serious bacterial infections in febrile infants younger than 90 days old

BACKGROUND

The aim of this study was to assess correlations between demographic, clinical and laboratory characteristics and the risk of serious bacterial infection (SBI) in febrile <90-day-old infants.

METHODS

Medical records of all infants younger than 90 days old hospitalized at Dana-Dwek Children's Hospital (2006-2008) for evaluation of fever were retrospectively reviewed. Data on clinical, laboratory and demographic characteristics were retrieved and evaluated.

RESULTS

Forty-eight of the 401 study infants (12%) had SBI: most of them had urinary tract infection (43 infants; 90% of all SBI), three infants had bacteremia, one had bacterial pneumonia and one had bacterial meningitis. Significant independent clinical predictors for the diagnosis of SBI included duration of fever, absence of rhinitis and the absence of lung and skin manifestations. Significant independent laboratory predictors were absolute neutrophil count (ANC), platelets, blood urea nitrogen and C-reactive protein (CRP) level. On receiver operating characteristic curve analysis, the CRP area under the curve (0.819) was significantly superior to ANC and leukocyte count.

CONCLUSION

Of the clinical and laboratory variables selected for evaluation, qualitative CRP was the strongest independent predictor for diagnosing SBI and a significantly better diagnostic marker than clinical characteristics, ANC and white blood cell count.

Incidence of serious bacterial infections in febrile children with sickle cell disease

OBJECTIVE

To determine the incidence of serious bacterial infections in febrile children with sickle cell disease and to describe the outcomes of children discharged from the pediatric emergency department.

METHODS

We conducted a retrospective chart review of 188 febrile patients with sickle cell disease presenting to our pediatric emergency department over a 10-year period. Serious bacterial infection was defined as bacteremia, meningitis, urinary tract infection, osteomyelitis, or pneumonia.

RESULTS

Our overall incidence rate for serious bacterial infections was 16.0% (95% confidence interval [CI] = 10.8% to 21.2%). Pneumonia had the highest incidence rate of 13.8% (95% CI = 8.8% to 18.8%). This was followed by bacteremia and urinary tract infections, both with incidence rates of 1.1% (95% CI = 0.0% to 2.5%). We had no cases of meningitis or osteomyelitis in our study group.

CONCLUSION

We had an incidence of 16.0% for serious bacterial infections in febrile children with sickle cell disease, with the majority of patients diagnosed with pneumonia.

Fever without source in infants and young children: dilemma in diagnosis and management

BACKGROUND

There is controversy surrounding the management of young children who have a fever without a source (FWS). Several strategies have been designed with the purpose of managing children with FWS.

AIMS

To assess the applicability of a standardized guideline for children up to 36 months of age with FWS.

SETTING

Pediatric emergency unit, Al-Adan Hospital, Kuwait City, Kuwait, from May 2011 to October 2011.

DESIGN

Prospective, cross-sectional study.

METHODS AND MATERIALS

The study involved children with FWS up to 36 months of age. The guideline classifies the risk of serious bacterial infection (SBI) according to the age of the child, the presence or absence of toxemia, clinical presentation, and laboratory screening tests.

RESULTS

A total of 481 children were included in the present study, but only 385 cases completed the study; 3.9% of patients had toxemia at the initial evaluation. We found 26 children with SBI (6.8%); 12 patients with SBI did not present with toxemia. In all, 40.4% of studied newborns were diagnosed as having a urinary tract infection, and 42.7% of patients as self-limited probable viral etiology. Of the 109 young infants without toxemia, 53.2% were classified as being at high risk of SBI. Of the 163 toddlers without toxemia, 72.4% were treated with antibiotics; 48.4% of patients received therapeutic treatment and 25.8% received empirical treatment.

CONCLUSION

The guideline followed in our pediatric emergency unit seemed to be appropriate in following up with these children using simple laboratory tests. The most frequent SBI in this sample was urinary tract infection.