Predictors of occult bacteremia in young febrile children in the era of heptavalent pneumococcal conjugated vaccine

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.

Clinical management of fever in children in Brazil: practical recommendations from an expert panel

The objective of this study was to answer several questions related to the assessment and treatment of fever, as well as other controversies that exist during its management in pediatric patients. First, an advisory board with medical experts was conducted to discuss the clinical journey of these patients, considering the main challenges and possible solutions. After this discussion, a non-systematic literature review was performed, between November 2019 and January 2020, to collect the most relevant evidence available in the scientific databases MEDLINE, Lilacs, and SciELO. A narrative review was carried out based on scientific evidence and on extensive experience of experts in clinical practice. The experts developed a set of recommendations and clarifications about the assessment of the severity of fever in pediatrics, the need for treatment and the choice of the most appropriate antipyretic. The most common controversies in the management of fever in pediatric patients were also addressed, such as alternating antipyretics, persistent fever, and dose equivalence. In primary management of pediatric patients, fever should be seen as a relevant symptom that requires treatment with antipyretics in potentially more complex or severe cases, when it causes discomfort to children or is associated with infectious diseases.

Hospital-acquired Pneumonia and Ventilator-associated Pneumonia in Children: A Prospective Natural History and Case-Control Study

BACKGROUND

Clinical trials for antibiotics designed to treat hospital-acquired and ventilator-associated bacterial pneumonias (HABP/VABP) are hampered by making these diagnoses in a way that is acceptable to the United States Food and Drug Administration and consistent with standards of care. We examined laboratory and clinical features that might improve pediatric HABP/VABP trial efficiency by identifying risk factors predisposing children to HABP/VABP and describing the epidemiology of pediatric HABP/VABP.

METHODS

We prospectively reviewed the electronic medical records of patients <18 years of age admitted to intensive and intermediate care units (ICUs) if they received qualifying respiratory support or were started on antibiotics for a lower respiratory tract infection or undifferentiated sepsis. Subjects were followed until HABP/VABP was diagnosed or they were discharged from the ICU. Clinical, laboratory and imaging data were abstracted using structured chart review. We calculated HABP/VABP incidence and used a stepwise backward selection multivariable model to identify risk factors associated with development of HABP/VABP.

RESULTS

A total of 862 neonates, infants and children were evaluated for development of HABP/VABP; 10% (82/800) of those receiving respiratory support and 12% (103/862) overall developed HABP/VABP. Increasing age, shorter height/length, longer ICU length of stay, aspiration risk, blood product transfusion in the prior 7 days and frequent suctioning were associated with increased odds of HABP/VABP. The use of noninvasive ventilation and gastric acid suppression were both associated with decreased odds of HABP/VABP.

CONCLUSIONS

Food and Drug Administration-defined HABP/VABP occurred in 10%-12% of pediatric patients admitted to ICUs. Risk factors vary by age group.

Using Machine Learning to Predict Bacteremia in Febrile Children Presented to the Emergency Department

Blood culture is frequently used to detect bacteremia in febrile children. However, a high rate of negative or false-positive blood culture results is common at the pediatric emergency department (PED). The aim of this study was to use machine learning to build a model that could predict bacteremia in febrile children. We conducted a retrospective case-control study of febrile children who presented to the PED from 2008 to 2015. We adopted machine learning methods and cost-sensitive learning to establish a predictive model of bacteremia. We enrolled 16,967 febrile children with blood culture tests during the eight-year study period. Only 146 febrile children had true bacteremia, and more than 99% of febrile children had a contaminant or negative blood culture result. The maximum area under the curve of logistic regression and support vector machines to predict bacteremia were 0.768 and 0.832, respectively. Using the predictive model, we can categorize febrile children by risk value into five classes. Class 5 had the highest probability of having bacteremia, while class 1 had no risk. Obtaining blood cultures in febrile children at the PED rarely identifies a causative pathogen. Prediction models can help physicians determine whether patients have bacteremia and may reduce unnecessary expenses.

Clinical prediction models for young febrile infants at the emergency department: an international validation study

OBJECTIVE

To assess the diagnostic value of existing clinical prediction models (CPM; ie, statistically derived) in febrile young infants at risk for serious bacterial infections.

METHODS

A systematic literature review identified eight CPMs for predicting serious bacterial infections in febrile children. We validated these CPMs on four validation cohorts of febrile children in Spain (age <3 months), France (age <3 months) and two cohorts in the Netherlands (age 1-3 months and >3-12 months). We evaluated the performance of the CPMs by sensitivity/specificity, area under the receiver operating characteristic curve (AUC) and calibration studies.

RESULTS

The original cohorts in which the prediction rules were developed (derivation cohorts) ranged from 381 to 15 781 children, with a prevalence of serious bacterial infections varying from 0.8% to 27% and spanned an age range of 0-16 years. All CPMs originally performed moderately to very well (AUC 0.60-0.93). The four validation cohorts included 159-2204 febrile children, with a median age range of 1.8 (1.2-2.4) months for the three cohorts <3 months and 8.4 (6.0-9.6) months for the cohort >3-12 months of age. The prevalence of serious bacterial infections varied between 15.1% and 17.2% in the three cohorts <3 months and was 9.8% for the cohort >3-12 months of age. Although discriminative values varied greatly, best performance was observed for four CPMs including clinical signs and symptoms, urine dipstick analyses and laboratory markers with AUC ranging from 0.68 to 0.94 in the three cohorts <3 months (ranges sensitivity: 0.48-0.94 and specificity: 0.71-0.97). For the >3-12 months' cohort AUC ranges from 0.80 to 0.89 (ranges sensitivity: 0.70-0.82 and specificity: 0.78-0.90). In general, the specificities exceeded sensitivities in our cohorts, in contrast to derivation cohorts with high sensitivities, although this effect was stronger in infants <3 months than in infants >3-12 months.

CONCLUSION

We identified four CPMs, including clinical signs and symptoms, urine dipstick analysis and laboratory markers, which can aid clinicians in identifying serious bacterial infections. We suggest clinicians should use CPMs as an adjunctive clinical tool when assessing the risk of serious bacterial infections in febrile young infants.

Occult bacteremia etiology following the introduction of 13-valent pneumococcal conjugate vaccine: a multicenter study in Spain

Little is known about occult bacteremia (OB) in Spain following the introduction of the 13-valent pneumococcal conjugated vaccine (PCV13). Our aim was to describe the microbiologic characteristics and management of OB among children aged 3-36 months in Spain in the era of PCV13. Data were obtained from a multicenter registry of positive blood cultures collected at 22 Spanish emergency departments (ED). Positive blood cultures performed on patients aged 3-36 months from 2011 to 2015 were retrospectively identified. Immunocompetent infants with a final diagnosis of OB were included. Non-well-appearing patients and patients with fever > 72 h were excluded. We analyzed 67 cases (median age 12.5 months [IQR 8.7-19.4]). Thirty-seven (54.4%) had received ≥ 1 dose of PCV. Overall, 47 (70.1%) were initially managed as outpatients (38.3% of them with antibiotic treatment). Phone contact was established with 43 (91.5%) of them after receiving the blood culture result and 11 (23.4%) were hospitalized with parenteral antibiotic. All patients did well. Streptococcus pneumoniae was isolated in 79.1% of the patients (42.2% of the isolated serotypes were included in the PCV13). S. pneumoniae remains the first cause of OB in patients attended in the ED, mainly with non-PCV13 serotypes. Most of the patients with OB were initially managed as outpatients with no adverse outcome.

Pneumococcal vaccinations effectively prevent blood culture-negative infections that resemble occult pneumococcal bacteraemia or bacteraemic pneumococcal pneumonia at one to 36 months of age

AIM

The occurrence of blood culture-positive pneumococcal bacteraemia and bacteraemic pneumonia decreased after large-scale pneumococcal vaccinations were introduced. The aim of this study was to evaluate the effect of pneumococcal vaccinations on hospitalisations due to blood culture-negative infections with fever and leucocytosis, without any other focus than pneumonic infiltration.

MATERIAL

This was a retrospective hospital chart review covering the prevaccination era of 2008-2009 and postvaccination era of 2012-2013. The number of study subjects with fever and blood leucocytosis of >17.5 × 10E9/L at one to 36 months of age was 202.

RESULTS

The incidence of hospitalisation for infections associated with fever and leucocytosis, when pneumonic infiltration was present on the chest radiograph, was 4.7/10 000/year, with a 95% confidence interval (95% CI) of 2.2-8.8 in children under 36 months in 2012-2013. When pneumonic infiltration was not present, the respective incidence was 14.6/10 000/year (95% CI: 9.6-21.1). The figure from the 2008-2009 prevaccination era was 11.3 (95% CI: 8.1-15.3) when pneumonic infiltration was present and 24.0/10 000/year (95% CI: 19.2-29.7) when pneumonic infiltration was absent.

CONCLUSION

This study provides evidence of the effectiveness of pneumococcal vaccinations in preventing blood culture-negative infections that resembled occult pneumococcal bacteraemia (pneumococcaemia) or bacteraemic pneumococcal pneumonia at one to 36 months of age.

Occult bacteraemia is uncommon in febrile infants who appear well, and close clinical follow-up is more appropriate than blood tests

AIM

The rate of paediatric occult bacteraemia after the introduction of the 13-valent pneumococcal conjugated vaccine is relatively unknown. We determined the rate, and identified isolated pathogens, in children aged three to 36 months who presented to a paediatric emergency department with fever, but otherwise appeared well. We also analysed the yield of laboratory parameters traditionally considered risk factors for occult bacteraemia.

METHODS

Children aged three to 36 months who were febrile, but otherwise appeared well, were included if they had blood tests in the paediatric emergency department between April 2010 and September 2012.

RESULTS

Of the 591 patients, only six (1.0%) had a true bacterial pathogen and three of those were Streptococcus pneumoniae (0.5%). None of the children with pneumococcal bacteraemia had been immunised. The contaminant rate was 2.7%, and an elevated band count was the best predictor of occult bacteraemia, with positive and negative likelihood ratios of 10 and 0.4, respectively. The yield of the other laboratory parameters was very limited.

CONCLUSION

In the era of the 13-valent pneumococcal conjugated vaccine, occult bacteraemia is an uncommon event in febrile children aged three to 36 who otherwise appear well and close follow-up should replace blood analysis in such cases.

Bacteremia in previously healthy children in emergency departments: clinical and microbiological characteristics and outcome

A blood culture (BC) is frequently requested in both patients with a suspected occult bacteremia/invasive infection as well as those with certain focal infections. Few data are available on the characteristics of patients in whom a bacteremia is identified in the Pediatric Emergency Department (PED). A prospective multicenter registry was established by the Spanish Pediatric Emergency Society. Epidemiological data, complementary test results, clinical management, and final outcome were recorded. Data from the first three years of the registry were analyzed. A true bacterial pathogen grew in 932 of 65,169 BCs collected [1.43 %; 95 % confidence interval (CI) 1.34-1.51 %], with 711 of them collected in patients without previously known bacteremia risk factors. Among them, 335 (47.1 %) were younger than 1 year old and 467 (65.7 %) had a normal Pediatric Assessment Triangle (PAT) on admission. Overall, the most frequently isolated bacterial species was Streptococcus pneumoniae (27.3 %; 47.6 % among patients with an altered PAT). The main pathogens were Escherichia coli (40.3 %) and S. agalactiae (35.7 %) among patients younger than 3 months, S. pneumoniae among patients 3-60 months old (40.0 %), and S. aureus (31.9 %) among patients over 60 months of age. Neisseria meningitidis was the leading cause of sepsis in patients older than 3 months. Eight patients died; none of them had a pneumococcal bacteremia and all had abnormal PAT findings on admission. S. pneumoniae is the main cause of bacteremia in patients without bacteremia risk factors who attended Spanish PEDs. Age and general appearance influence the frequency of each bacterial species. General appearance also influences the associated mortality.

Evaluation of child with fever without source: review of literature and update

Fever is one of the most common reasons for a visit to the primary care provider or the emergency department. Traditionally, clinicians have used various risk-stratification strategies to identify serious bacterial infections (SBI) without an obvious source in febrile children, because missed bacterial infections in such children can result in meningitis, sepsis, and death; therefore, early and accurate identification of SBIs is critical. Infants aged less than 60 to 90 days are at greatest risk of SBI. The epidemiology of SBI continues to evolve, especially after the successful introduction of conjugate vaccines against Streptococcus pneumoniae and Haemophilus influenzae.

Fever in the pediatric patient

Fever is the most common reason that children and infants are brought to emergency departments. Emergency physicians face the challenge of quickly distinguishing benign from life-threatening conditions. The management of fever in children is guided by the patient's age, immunization status, and immune status as well as the results of a careful physical examination and appropriate laboratory tests and radiographic views. In this article, the evaluation and treatment of children with fevers of known and unknown origin are described. Causes of common and dangerous conditions that include fever in their manifestation are also discussed.

Pneumococcemia in children--a retrospective study before universal pneumococcal vaccinations

AIM

To evaluate the incidence and characteristics of blood culture-positive occult pneumococcemia compared with blood culture-positive pneumococcal pneumonia in children.

METHODS

In years 2001-2010, 105 children with positive blood cultures for Streptococcus pneumoniae were identified from hospital electronic files. The patient cards were retrospectively charted for clinical and laboratory data, and 38 patients had and 67 had not pneumonia.

RESULTS

The annual incidence of pneumococcemia was, on average, 29.0/10 000 at 0-12 months, 5.3/10 000 at 13-24 months and 1.9/10 000 at 2-4 years of ages, with no increasing or decreasing trend. The incidence of bacteraemic pneumococcal pneumonia increased (p = 0.022) during the study period. The duration of fever before hospitalization (<24 h 73.9% vs. 25.0%, p = 0.022) and the duration of intravenous antibiotics, usually G-penicillin (median 72 vs. 96 h, p = 0.021) was shorter in pneumococcemia patients. On admission, blood leucocyte count was higher in pneumococcemia (mean 26.6 vs. 21.9 × 10E9/L, p = 0.012), but serum CRP was higher in pneumonia (median 160 vs. 67.4 mg/L, p < 0.001). The serotypes 6B and 14 caused 53.2% of pneumococcemia cases.

CONCLUSION

The incidence of pneumococcemia was highest in 1-2-year-old children, and typical for pneumococcemia was rapid onset of fever, high blood leucocyte count and a modestly elevated CRP on admission.

Serum hepcidin: indication of its role as an "acute phase" marker in febrile children

Background

Hepcidin is classified as a type II acute phase protein; its production is a component of the innate immune response to infections.

Objective

To evaluate the alterations of serum hepcidin in children during and following an acute febrile infection.

Materials and methods

22 children with fever of acute onset (< 6 hours) admitted to the 2^nd Department of Pediatrics-University of Athens. Based on clinical and laboratory findings our sample formed two groups: the viral infection group (13 children) and the bacterial infection group (9 children). Hepcidin, ferritin and serum iron measurements were performed in all subjects.

Results

Serum hepcidin values did not differ notably between children with viral and bacterial infection, but a significant reduction of hepcidin was noted in both groups post-infection.

Conclusion

Our study provides clinical pediatric data on the role of hepcidin in the face of an acute infection. In our sample of children, hepcidin was found to rise during the acute infection and fall post-infection.

Clinical prediction model to aid emergency doctors managing febrile children at risk of serious bacterial infections: diagnostic study

OBJECTIVE

To derive, cross validate, and externally validate a clinical prediction model that assesses the risks of different serious bacterial infections in children with fever at the emergency department.

DESIGN

Prospective observational diagnostic study.

SETTING

Three paediatric emergency care units: two in the Netherlands and one in the United Kingdom.

PARTICIPANTS

Children with fever, aged 1 month to 15 years, at three paediatric emergency care units: Rotterdam (n=1750) and the Hague (n=967), the Netherlands, and Coventry (n=487), United Kingdom. A prediction model was constructed using multivariable polytomous logistic regression analysis and included the predefined predictor variables age, duration of fever, tachycardia, temperature, tachypnoea, ill appearance, chest wall retractions, prolonged capillary refill time (>3 seconds), oxygen saturation <94%, and C reactive protein.

MAIN OUTCOME MEASURES

Pneumonia, other serious bacterial infections (SBIs, including septicaemia/meningitis, urinary tract infections, and others), and no SBIs.

RESULTS

Oxygen saturation <94% and presence of tachypnoea were important predictors of pneumonia. A raised C reactive protein level predicted the presence of both pneumonia and other SBIs, whereas chest wall retractions and oxygen saturation <94% were useful to rule out the presence of other SBIs. Discriminative ability (C statistic) to predict pneumonia was 0.81 (95% confidence interval 0.73 to 0.88); for other SBIs this was even better: 0.86 (0.79 to 0.92). Risk thresholds of 10% or more were useful to identify children with serious bacterial infections; risk thresholds less than 2.5% were useful to rule out the presence of serious bacterial infections. External validation showed good discrimination for the prediction of pneumonia (0.81, 0.69 to 0.93); discriminative ability for the prediction of other SBIs was lower (0.69, 0.53 to 0.86).

CONCLUSION

A validated prediction model, including clinical signs, symptoms, and C reactive protein level, was useful for estimating the likelihood of pneumonia and other SBIs in children with fever, such as septicaemia/meningitis and urinary tract infections.

Bacteremia in feverish children presenting to the emergency department: a retrospective study and literature review

AIM

To evaluate the incidence of bacteremia, and the isolated pathogens, in well-appearing children with fever without source (FWS) presenting to the pediatric emergency department (PED), after pneumococcal conjucate vaccine - 7 valent (PCV-7) widespread introduction in the Veneto region of north-eastern Italy, and to review the main literature contributions on the subject.

METHODS

Blood cultures performed at the PED of Padova from 1 June 2006 to 31 January 2009 in febrile children aged 1-36 months were retrospectively retrieved. Medical records of previously healthy well-appearing children with FWS were identified and reviewed.

RESULTS

The study finally included 392 patients. Bacteremia rate was 0.34% (95% CI 0-1) in the age group 3-36 months and 2% (95% CI 0-4.7) in infants 1-3 months. No Streptococcus pneumoniae was isolated. The literature review identified 10 relevant studies carried out in the USA and Spain showing an overall bacteremia rate <1% for feverish children aged 3-36 months, with values <0.5% in settings with high PCV-7 coverage.

CONCLUSION

Overall bacteremia rate is currently <0.5% in well-appearing children aged 3-36 months with FWS attending the PED in areas with PCV-7 widespread vaccination and is sufficiently low to preclude laboratory testing in favour of close follow-up. Further research is needed to evaluate a more conservative approach in infants 2-3 months of age.

A case of functional asplenia and pneumococcal sepsis

Asplenia may refer to the spleen's surgical removal, functional impairment, or congenital absence. It is a risk factor for the development of severe bacterial infection. Functional asplenia is likely the most common presentation of this entity and has many etiologies. Those that are previously undiagnosed may present completely well until an episode of overt sepsis develops. The true incidence of mortality secondary to functional asplenia remains elusive. As lifetime mortality remains exceedingly high in the asplenic population regardless of etiology, markers of hyposplenism are important to detect. The present report describes an infant with trisomy 21 and previously undiagnosed functional asplenia who ultimately experienced overwhelming pneumococcal sepsis with features of Waterhouse-Friderichsen syndrome and died within 12 hours of initial presentation. It is a poignant reminder of what features to be cognizant of on peripheral blood smear in a previously well child, who may be at risk for a devastating consequence.