Epidemiology of Bacteremia in Febrile Infants Aged 60 Days and Younger

Preclinical validation of an Escherichia coli O-antigen glycoconjugate for the prevention of serotype O1 invasive disease

A US collection of invasive Escherichia coli serotype O1 bloodstream infection (BSI) isolates were assessed for genotypic and phenotypic diversity as the basis for designing a broadly protective O-antigen vaccine. Eighty percent of the BSI isolate serotype O1 strains were genotypically ST95 O1:K1:H7. The carbohydrate repeat unit structure of the O1a subtype was conserved in the three strains tested representing core genome multi-locus sequence types (MLST) sequence types ST95, ST38, and ST59. A long-chain O1a CRM197 lattice glycoconjugate antigen was generated using oxidized polysaccharide and reductive amination chemistry. Two ST95 strains were investigated for use in opsonophagocytic assays (OPA) with immune sera from vaccinated animals and in murine lethal challenge models. Both strains were susceptible to OPA killing with O1a glycoconjugate post-immune sera. One of these, a neonatal sepsis strain, was found to be highly lethal in the murine challenge model for which virulence was shown to be dependent on the presence of the K1 capsule. Mice immunized with the O1a glycoconjugate were protected from challenges with this strain or a second, genotypically related, and similarly virulent neonatal isolate. This long-chain O1a CRM197 lattice glycoconjugate shows promise as a component of a multi-valent vaccine to prevent invasive E. coli infections.

IMPORTANCE

The Escherichia coli serotype O1 O-antigen serogroup is a common cause of invasive bloodstream infections (BSI) in populations at risk such as newborns and the elderly. Sequencing of US BSI isolates and structural analysis of O polysaccharide antigens purified from strains that are representative of genotypic sub-groups confirmed the relevance of the O1a subtype as a vaccine antigen. O polysaccharide was purified from a strain engineered to produce long-chain O1a O-antigen and was chemically conjugated to CRM197 carrier protein. The resulting glycoconjugate elicited functional antibodies and was protective in mice against lethal challenges with virulent K1-encapsulated O1a isolates.

Safely Doing Less for Febrile Infants: Reviewing Management in the Setting of the 2021 American Academy of Pediatrics Clinical Practice Guideline

For more than 4 decades, pediatricians have sought the best practices for effectively managing well-appearing young febrile infants. In 2021, the American Academy of Pediatrics released a clinical practice guideline for the management of well-appearing febrile infants aged 8 to 60 days. The guideline incorporates advancements in testing, such as biomarkers and diagnostic testing in the setting of changing epidemiology, to help risk stratify infants in the newly formed group age 22 to 28 days as well as the group age 29 to 60 days. The new guideline uses inflammatory markers (procalcitonin, C-reactive protein, absolute neutrophil count, and a temperature >38.4°C) to identify infants at low risk for invasive bacterial infection who can potentially avoid the invasive procedures of lumbar puncture, hospitalization, and broad-spectrum antimicrobials. Because of continued ambiguity, incorporating shared decision-making with families in the care of these infants will be important, as will ongoing clinical research to better inform future practice. [Pediatr Ann. 2024;53(6):e202-e207.].

Improving Guideline-Concordant Care for Febrile Infants Through a Quality Improvement Initiative

OBJECTIVES

We aimed to examine the impact of a quality improvement (QI) collaborative on adherence to specific recommendations within the American Academy of Pediatrics' Clinical Practice Guideline (CPG) for well-appearing febrile infants aged 8 to 60 days.

METHODS

Concurrent with CPG release in August 2021, we initiated a QI collaborative involving 103 general and children's hospitals across the United States and Canada. We developed a multifaceted intervention bundle to improve adherence to CPG recommendations for 4 primary measures and 4 secondary measures, while tracking 5 balancing measures. Primary measures focused on guideline recommendations where deimplementation strategies were indicated. We analyzed data using statistical process control (SPC) with baseline and project enrollment from November 2020 to October 2021 and the intervention from November 2021 to October 2022.

RESULTS

Within the final analysis, there were 17 708 infants included. SPC demonstrated improvement across primary and secondary measures. Specifically, the primary measures of appropriately not obtaining cerebrospinal fluid in qualifying infants and appropriately not administering antibiotics had the highest adherence at the end of the collaborative (92.4% and 90.0% respectively). Secondary measures on parent engagement for emergency department discharge of infants 22 to 28 days and oral antibiotics for infants 29 to 60 days with positive urinalyses demonstrated the greatest changes with collaborative-wide improvements of 16.0% and 20.4% respectively. Balancing measures showed no change in missed invasive bacterial infections.

CONCLUSIONS

A QI collaborative with a multifaceted intervention bundle was associated with improvements in adherence to several recommendations from the AAP CPG for febrile infants.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

An all-inclusive model for predicting invasive bacterial infection in febrile infants age 7-60 days

BACKGROUND

Invasive bacterial infections (IBIs) in febrile infants are rare but potentially devastating. We aimed to derive and validate a predictive model for IBI among febrile infants age 7-60 days.

METHODS

Data were abstracted retrospectively from electronic records of 37 emergency departments (EDs) for infants with a measured temperature >=100.4 F who underwent an ED evaluation with blood and urine cultures. Models to predict IBI were developed and validated respectively using a random 80/20 dataset split, including 10-fold cross-validation. We used precision recall curves as the classification metric.

RESULTS

Of 4411 eligible infants with a mean age of 37 days, 29% had characteristics that would likely have excluded them from existing risk stratification protocols. There were 196 patients with IBI (4.4%), including 43 (1.0%) with bacterial meningitis. Analytic approaches varied in performance characteristics (precision recall range 0.04-0.29, area under the curve range 0.5-0.84), with the XGBoost model demonstrating the best performance (0.29, 0.84). The five most important variables were serum white blood count, maximum temperature, absolute neutrophil count, absolute band count, and age in days.

CONCLUSION

A machine learning model (XGBoost) demonstrated the best performance in predicting a rare outcome among febrile infants, including those excluded from existing algorithms.

IMPACT

Several models for the risk stratification of febrile infants have been developed. There is a need for a preferred comprehensive model free from limitations and algorithm exclusions that accurately predicts IBIs. This is the first study to derive an all-inclusive predictive model for febrile infants aged 7-60 days in a community ED sample with IBI as a primary outcome. This machine learning model demonstrates potential for clinical utility in predicting IBI.

Rate of Urinary Tract Infections, Bacteremia, and Meningitis in Preterm and Term Infants

BACKGROUND AND OBJECTIVES

There are very limited data on the rate of urinary tract infections (UTI), bacteremia, and meningitis in preterm infants with fever. Many of the studies on the incidence of these infections excluded preterm infants. This study compared the rate of these infections in preterm infants born at 32-36 weeks to term infants born at 37-42 weeks.

METHODS

A multicenter observational cohort study was conducted to evaluate rates of UTI, bacteremia, and meningitis in term and preterm infants 8-60 days of age with a diagnosis of fever from 2016 through 2022 using encounter data from children's hospitals in the Pediatric Health Information System.

RESULTS

There were 19 507 total febrile infants identified, of which 2162 were preterm and 17 345 were term. Preterm infants had a lower rate of UTI than term infants (1.8% confidence interval [CI] [1.3-2.5] vs 3.0% CI [2.7-3.2], P = .001). Preterm and term infants did not have statistically different rates of bacteremia (1.5% CI [1.3-1.7] vs 1.2% CI [0.8-1.8], P = .44) or meningitis (0.16% CI [0.1-0.2] vs 0.05% CI [0-0.2], P = .36).

CONCLUSIONS

There was no difference in the rate of bacteremia or meningitis between term and preterm infants in a large multicenter cohort of febrile infants. Preterm infants had a lower rate of UTI than term infants. This is the first multicenter study to compare UTI, bacteremia, and meningitis between term and preterm febrile infants.

La prise en charge des nourrissons de 90 jours ou moins, fiévreux mais dans un bon état général

On constate des pratiques très variées en matière d'évaluation et de prise en charge des jeunes nourrissons fiévreux. Bien que la plupart des jeunes nourrissons fiévreux mais dans un bon état général soient atteints d'une maladie virale, il est essentiel de détecter ceux qui sont à risque de présenter des infections bactériennes invasives, notamment une bactériémie et une méningite bactérienne. Le présent document de principes porte sur les nourrissons de 90 jours ou moins dont la température rectale est de 38,0 °C ou plus, mais qui semblent être dans un bon état général. Il est conseillé d'appliquer les récents critères de stratification du risque pour orienter la prise en charge, ainsi que d'intégrer la procalcitonine à l'évaluation diagnostique. Les décisions sur la prise en charge des nourrissons qui satisfont aux critères de faible risque devraient refléter la probabilité d'une maladie, tenir compte de l'équilibre entre les risques et les préjudices potentiels et faire participer les parents ou les proches aux décisions lorsque diverses options sont possibles. La prise en charge optimale peut également dépendre de considérations pragmatiques, telles que l'accès à des examens diagnostiques, à des unités d'observation, à des soins tertiaires et à un suivi. Des éléments particuliers, tels que la mesure de la température, le risque d'infection invasive à Herpes simplex et la fièvre postvaccinale, sont également abordés.

Management of well-appearing febrile young infants aged ≤90 days

The evaluation and management of young infants presenting with fever remains an area of significant practice variation. While most well-appearing febrile young infants have a viral illness, identifying those at risk for invasive bacterial infections, specifically bacteremia and bacterial meningitis, is critical. This statement considers infants aged ≤90 days who present with a rectal temperature ≥38.0°C but appear well otherwise. Applying recent risk-stratification criteria to guide management and incorporating diagnostic testing with procalcitonin are advised. Management decisions for infants meeting low-risk criteria should reflect the probability of disease, consider the balance of risks and potential harm, and include parents/caregivers in shared decision-making when options exist. Optimal management may also be influenced by pragmatic considerations, such as access to diagnostic investigations, observation units, tertiary care, and follow-up. Special considerations such as temperature measurement, risk for invasive herpes simplex infection, and post-immunization fever are also discussed.

Outcomes of Infants Who Are Febrile Aged 29-90 Days Discharged from the Emergency Department

OBJECTIVE

To evaluate the characteristics and outcomes of infants aged 29-90 days who are febrile discharged from the pediatric emergency department (ED).

STUDY DESIGN

This was a multicenter, retrospective cohort study of infants aged 29-90 days who visited any of the 7 Clalit Health Services pediatric EDs in Israel between January 1, 2019, and March 31, 2022. Infants who were febrile discharged from the ED after having blood and urine cultures taken were included. The primary outcome measure was the incidence of return visit (RV) to an ED. Secondary outcome measures were the incidence of invasive bacterial infection, urinary tract infection, pediatric intensive care unit admissions, and deaths. We assessed variables associated with the primary outcomes.

RESULTS

A total of 1647 infants were included. Their median (IQR) age at ED visit was 58.5 (47.7, 72.7) days, 53.1% were male. A total of 329 patients (20%) returned to the ED within 120 hours. Overall, 7.8% of discharged infants had a positive urine culture, 4 (0.2%) had a positive blood culture, and none had meningitis. One patient was admitted to the pediatric intensive care unit, and there was no death. Abnormal C-reactive protein was associated with RV among 61- to 90-day-old infants.

CONCLUSIONS

Infants aged 29-90 days who were febrile and discharged following a protocol-driven pathway from the pediatric ED had a relatively high RV rate. However, the rate of urinary tract infection was relatively low, and rate of invasive bacterial infection was extremely low. There were no deaths or serious sequelae.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Clinical characteristics and outcomes in febrile infants aged 29-90 days with urinary tract infections and cerebrospinal fluid pleocytosis

Introduction

Fever without a focus is a common reason for medical evaluations, hospitalizations, and the antimicrobial treatment of infants younger than 90 days. The presence of cerebrospinal fluid (CSF) pleocytosis could be challenge for clinicians who treat febrile young infants with urinary tract infection (UTI). We evaluated the factors associated with sterile CSF pleocytosis and the clinical outcomes of the patients.

Methods

A retrospective review of patients aged 29-90 days with febrile UTIs who underwent a non-traumatic lumbar puncture (LP) at Pusan National University Hospital from January 2010 to December 2020 was conducted. CSF pleocytosis was defined as white blood cell (WBC) counts ≥9/mm³.

Results

A total of 156 patients with UTI were eligible for this study. Four (2.6%) had concomitant bacteremia. However, no patients had culture-proven bacterial meningitis. In correlation analysis, although weak strength, CSF WBC counts were positively correlated with C-reactive protein (CRP) level (Spearman r = 0.234; P = 0.003). Thirty-three patients had CSF pleocytosis [21.2%; 95% confidential interval (CI), 15.5-28.2]. The time from fever onset to the hospital visit, peripheral blood platelet counts, and CRP level at admission were statistically significant in patients with sterile CSF pleocytosis compared to those without CSF pleocytosis. In the multiple logistic regression, only CRP was independently associated with sterile CSF pleocytosis (cutoff, 3.425 mg/dl; adjusted odds ratio, 2.77; 95% CI, 1.19-6.88). The proportion of fever defervescence by hospital day 2 was 87.9% in patients with CSF pleocytosis and 89.4% in those without CSF pleocytosis (P = 0.759). There was no statistical difference in the fever defervescence curves between the two patient groups (P = 0.567). No patients had neurological manifestations or complications.

Conclusions

Coexisting sterile CSF pleocytosis among febrile infants with UTIs suggest a systemic inflammatory response. However, the clinical outcomes between the two groups were similar. A selective LP should be considered in young infants with evidence of UTI, and inappropriate antibiotic therapy for sterile CSF pleocytosis should be avoided.

Updates in pediatric emergency medicine for 2022

As a relatively new field, there has been a recent explosion in evidence around the management of children in the emergency department (ED). This review highlights 10 articles published in the last year providing evidence that is germane to the care of children by emergency medicine (EM) physicians. There is a focus on high prevalence conditions, such as fever and trauma, as well as interventions that can improve mortality, such as cardiopulmonary resuscitation and massive transfusion.

Temperature threshold in the screening of bacterial infections in young infants with hypothermia

BACKGROUND

Young infants with hypothermia presenting to the emergency department (ED) are at risk for serious bacterial infections (SBI), however there is no consensus temperature to prompt evaluation for SBI among these children. We sought to statistically derive a temperature threshold to guide detection of SBI in young infants with hypothermia presenting to the ED.

METHODS

We performed a cross-sectional study of infants ≤90 days old presenting to four academic paediatric EDs in the United States of America from January 2015 through December 2019 with a rectal temperature of ≤36.4°C. Our primary outcomes were SBI, defined as urinary tract infection (UTI), bacteraemia and/or bacterial meningitis, and invasive bacterial infections (IBI, limited to bacteraemia and/or bacterial meningitis). We constructed receiver operating characteristic (ROC) curves to evaluate an optimally derived cutpoint for minimum ED temperature and presence of SBI or IBI.

RESULTS

We included 3376 infants, of whom SBI were found in 62 (1.8%) and IBI in 16 (0.5%). The most common infection identified was Escherichia coli UTI. Overall, cohort minimum median temperature was 36.2°C (IQR 36.0°C-36.4°C). Patients with SBI and IBI had lower median temperatures, 35.8°C (IQR 35.8°C-36.3°C) and 35.4°C (IQR 35.7°C-36.3°C), respectively, compared with those without corresponding infections (both p<0.05). Using an outcome of SBI, the area under the ROC curve (AUROC) was 61.0% (95% CI 54.1% to 67.9%). At a cutpoint of 36.2°C, sensitivity was 59.7% and specificity was 59.2%. When using an outcome of IBI, the AUROC was 65.9% (95% CI 51.1% to 80.6%). Using a cutpoint of 36.1°C in this model resulted in a sensitivity of 68.8% and specificity of 60.1%.

CONCLUSION

Young infants with SBI and IBI presented with lower temperatures than infants without infections. However, there was no temperature threshold to reliably identify SBI or IBI. Further research incorporating clinical and laboratory parameters, in addition to temperature, may help to improve risk stratification for these vulnerable patients.

The Incidence of Serious/Invasive Bacterial Diseases in Infants 90 Days Old or Younger at an Emergency Hospital in Japan

Background The incidence of severe bacterial infections (SBIs) in infants aged ≤90 days is thought to have decreased because of widespread vaccination programs. However, relevant epidemiological data in Japan are scarce. Materials and methods This observational, single-center study investigated the epidemiology of fever in infants aged ≤90 days. SBI was defined as the presence of meningitis, urinary tract infections (UTIs), or bacteremia. Invasive bacterial infection (IBI) was defined as the presence of meningitis, bacteremic UTI, or bacteremia. We determined the incidence of UTIs, bacteremia, meningitis, SBIs, and IBIs in the following three age groups: 0-28, 29-60, and 61-90 days. We subsequently calculated the relative incidence for the groups aged 29-60 and 61-90 days, using the group aged 0-28 days as the reference group.  Results Herein, 58, 124, and 166 infants were included in the 0-28 days, 29-60 days, and 61-90 days age groups, respectively. Of the total number of patients, 15.5%, 8.9%, and 16.9% in the 0-28 days, 29-60 days, and 61-90 days age groups, respectively, were diagnosed with SBI. The relative incidences were 1 for the 0-28 days group (reference group), 0.67 for the 29-60 days group (95% confidence interval [CI], 0.39-1.15), and 1.08 for the 61-90 days group (95% CI, 0.58-2.00). Of the total number of patients, 10.3%, 3.2%, and 0.6% in the 0-28 days, 29-60 days, and 61-90 days age groups, respectively, were diagnosed with IBI. Relative incidences were 1 (reference group), 0.50 (95% CI, 0.29-0.88), and 0.28 (95% CI, 0.19-0.41) for the 0-28 days, 29-60 days, and 61-90 days age groups, respectively. All cases of IBI were caused by Group B streptococcus (GBS), except for two cases of bacteremia, which were caused by Haemophilus influenzae.  Conclusion The incidence of SBI was similar in the 0-28 days and 61-90 days age groups. However, the incidence of IBI decreased with increasing age. The incidence of UTIs was highest in the 61-90 days age group, and that of meningitis and bacteremia decreased with increasing age.

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.

Following Birth Hospitalization: Invasive Bacterial Infections in Preterm Infants Aged 7-90 Days

OBJECTIVE

To assess the incidence rate of invasive bacterial infections in preterm infants and compare invasive bacterial infection rates and pathogens between preterm and full-term infants at age 7-90 days.

STUDY DESIGN

This is a retrospective cohort study of the incidence rate of invasive bacterial infections among all infants born at Kaiser Permanente Northern California (KPNC), with blood and cerebrospinal fluid cultures collected between 7 and 90 days of chronological age from outpatient clinics, from emergency departments, and in the first 24 hours of hospitalization presenting for care between January 1, 2005, and December 31, 2017. Incidence rates of invasive bacterial infection by chronological age and postmenstrual age (PMA) and pathogens were compared between preterm and full-term infants.

RESULTS

Between January 1, 2005, and December 31, 2017, a total of 479 729 infants were born at KPNC, including 440 070 full-term infants and 39 659 preterm infants. There were 283 cases of bacteremia in 282 infants. The incidence rate of invasive bacterial infection was significantly higher for preterm infants compared with full-term infants. The highest incidence rates of invasive bacterial infection were in preterm infants at chronological age 7-28 days and/or 37-39 weeks PMA. There was a trend toward lower rates of invasive bacterial infection with increasing PMA in preterm infants aged 61-90 days. Preterm infants aged 29-60 days or at ≥40 weeks PMA and those aged 61-90 days or at ≥43 weeks PMA had a rate of invasive bacterial infection equivalent to the overall rate seen in full-term infants of the same chronological age group. The distribution of pathogens causing bacteremia and meningitis did not differ between preterm and full-term infants.

CONCLUSION

PMA and chronological age together were more useful than either alone in informing the incidence rate of invasive bacterial infection in preterm infants during the first 90 days of life.

Changes in Etiology of Invasive Bacterial Infections in Infants Under 3 Months of Age in Korea, 2006-2020

OBJECTIVES

Invasive bacterial infection (IBI) causes a significant burden in infants. In this study, we analyzed changes in epidemiology of IBI among infants in Korea.

METHODS

A retrospective multicenter-based surveillance for IBIs in infants <3 months of age was performed during 2006-2020. Cases were classified as an early-onset disease (EOD) (0-6 days) or late-onset disease (LOD) (7-89 days). The temporal trend change in proportion of pathogens was analyzed.

RESULTS

Among 1545 cases, the median age was 28 days (IQR: 12, 53) and EOD accounted for 17.7%. Among pathogens, S. agalactiae (40.4%), E. coli (38.5%), and S. aureus (17.8%) were the most common and attributed for 96.7%. Among EOD (n = 274), S. agalactiae (45.6%), S. aureus (31.4%), E. coli (17.2%) and L. monocytogenes (2.9%) were most common. Among LOD (n = 1274), E. coli (43.1%), S. agalactiae (39.3%), S. aureus (14.9%) and S. pneumoniae (1.3%) were most common. In the trend analysis, the proportion of S. aureus (r s = -0.850, P < 0.01) decreased significantly, while that of S. agalactiae increased (r s = 0.781, P < 0.01).

CONCLUSION

During 2006-2020, among IBI in infants <3 months of age, S. agalactiae, E. coli, and S. aureus were most common and an increasing trend of S. agalactiae was observed.

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.

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

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

METHODS

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

RESULTS

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

CONCLUSION

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

Serious Bacterial Infections in Young Febrile Infants With Positive Urinalysis Results

It is unknown whether febrile infants 29 to 60 days old with positive urinalysis results require routine lumbar punctures for evaluation of bacterial meningitis.

OBJECTIVE

To determine the prevalence of bacteremia and/or bacterial meningitis in febrile infants ≤60 days of age with positive urinalysis (UA) results.

METHODS

Secondary analysis of a prospective observational study of noncritical febrile infants ≤60 days between 2011 and 2019 conducted in the Pediatric Emergency Care Applied Research Network emergency departments. Participants had temperatures ≥38°C and were evaluated with blood cultures and had UAs available for analysis. We report the prevalence of bacteremia and bacterial meningitis in those with and without positive UA results.

RESULTS

Among 7180 infants, 1090 (15.2%) had positive UA results. The risk of bacteremia was higher in those with positive versus negative UA results (63/1090 [5.8%] vs 69/6090 [1.1%], difference 4.7% [3.3% to 6.1%]). There was no difference in the prevalence of bacterial meningitis in infants ≤28 days of age with positive versus negative UA results (∼1% in both groups). However, among 697 infants aged 29 to 60 days with positive UA results, there were no cases of bacterial meningitis in comparison to 9 of 4153 with negative UA results (0.2%, difference -0.2% [-0.4% to -0.1%]). In addition, there were no cases of bacteremia and/or bacterial meningitis in the 148 infants ≤60 days of age with positive UA results who had the Pediatric Emergency Care Applied Research Network low-risk blood thresholds of absolute neutrophil count <4 × 103 cells/mm3 and procalcitonin <0.5 ng/mL.

CONCLUSIONS

Among noncritical febrile infants ≤60 days of age with positive UA results, there were no cases of bacterial meningitis in those aged 29 to 60 days and no cases of bacteremia and/or bacterial meningitis in any low-risk infants based on low-risk blood thresholds in both months of life. These findings can guide lumbar puncture use and other clinical decision making.

Annual Trend in Lumbar Puncture for Infants Younger Than 3 Months Hospitalized With Suspected Serious Bacterial Infection: A Nationwide Inpatient Database Study

BACKGROUND

A lumbar puncture is no longer necessary in febrile infants younger than 3 months when they are at low risk of serious bacterial infection because the risk factors for a severe bacterial infection have been identified. The purpose of this study was to identify the annual trend in the proportion of lumbar punctures in infants with suspected serious bacterial infections using a national inpatient database in Japan.

METHODS

Using the Diagnosis Procedure Combination database, we identified infants < 3 months of age who underwent blood and urine culture tests on admission from April 2011 to March 2020 in Japan.

RESULTS

In total, 44,910 eligible infants were included in the study. The proportion of lumbar punctures decreased gradually from 57.9% to 50.4% in infants 4-28 days old and from 54.5% to 37.3% in infants 29-89 days old between 2011 and 2019. Of the 18 hospitals, 15 (83.3%) recorded a lumbar puncture proportion of >50% in 2011 and 7 (38.9%) recorded >50% in 2019. In 3 hospitals, the proportion of lumbar punctures remained >75% in 2019.

CONCLUSION

The proportion of lumbar punctures with hospitalized infants admitted with blood and urine culture tests decreased over the years, and this trend was greater in infants 29-89 days of age. The reduction in the proportion of lumbar punctures varied widely among the hospitals.

Rochester Criteria and Yale Observation Scale Score to Evaluate Febrile Neonates with Invasive Bacterial Infection

BACKGROUND

Febrile neonates undergo lumbar puncture (LP), empiric antibiotic administration, and admission for increased risk of invasive bacterial infection (IBI), defined as bacteremia and meningitis.

OBJECTIVE

Measure IBI prevalence in febrile neonates, and operating characteristics of Rochester Criteria (RC), Yale Observation Scale (YOS) score, and demographics as a low-risk screening tool.

METHODS

Secondary analysis of healthy febrile infants < 60 days old presenting to any of 26 emergency departments in the Pediatric Emergency Care Applied Research Network between December 2008 and May 2013. Of 7334 infants, 1524 met our inclusion criteria of age ≤ 28 days. All had fevers and underwent evaluation for IBI. Receiver operator characteristic (ROC) curve and transparent decision tree analysis were used to determine the applicability of reassuring RC, YOS, and age parameters as an IBI low-risk screening tool.

RESULTS

Of 1524 neonates, 2.9% had bacteremia and 1.5% had meningitis. After applying RC and YOS, 15 neonates were incorrectly identified as low risk for IBI (10 bacteremia, 4 meningitis, 1 bacteremia, and meningitis). Age ≤ 18 days was a statistically significant variable ROC (area under curve 0.63, p < 0.05). Incorporating age > 18 days as low-risk criteria with reassuring RC and YOS misclassified 7 IBI patients (6 bacteremia, 1 meningitis).

CONCLUSION

Thirty percent of febrile neonates met low-risk criteria, age > 18 days, reassuring RC and YOS, and could avoid LP and empiric antibiotics. Our low-risk guidelines may improve patient safety and reduce health care costs by decreasing lab testing for cerebrospinal fluid, empiric antibiotic administration, and prolonged hospitalization. These results are hypothesis-generating and should be verified with a randomized prospective study.

Late-onset Group B Streptococcus Bacteremia Evaluated in the Pediatric Emergency Department and Risk Factors for Severe Infection

BACKGROUND

To describe the infants presenting to pediatric emergency departments (PEDs) and diagnosed with group B Streptococcus (GBS) late-onset disease (LOD) bacteremia and identify risk factors for severe infection and pediatric intensive care unit (PICU) admission.

METHODS

Observational study and subanalysis of a multicenter prospective registry. Setting: pediatric emergency department. Inclusion criteria: infants between 7 and 89 days of age with positive blood culture for GBS seen between 2011 and 2016 at any of 22 Spanish PEDs. Main outcome: risk factors (clinical and laboratory variables) for severe infection (sepsis/septic shock or meningitis) and PICU admission. Second, the prevalence of poor outcomes (acute complications, sequelae or death).

RESULTS

Among 118 patients with LOD, 74 (62.7%) presented a severe infection: 66 sepsis/septic shock (11 with associated meningitis) and 8 meningitis. Thirty-five patients (29.7%) were admitted to a PICU. An altered Pediatric Assessment Triangle (PAT) upon arrival and leukopenia were the only independent risk factors for severe infection [odds ratio (OR): 43.6; 95% confidence interval (CI): 8.1-235.7, P < 0.01] and PICU admission (OR: 11.6; 95% CI: 1.5-91.4; P < 0.019), respectively. Six patients (5.1%) developed a poor outcome, including 2 deaths (1.7%); all had an altered PAT, elevated procalcitonin (range 4.7-100 ng/ml), and were diagnosed with sepsis/septic shock and admitted to a PICU. Four developed leukopenia.

CONCLUSIONS

Infants with GBS LOD frequently develop sepsis/septic shock and bacterial meningitis, associated with non-negligible morbidity and mortality. Clinical appearance was the only risk factor for severe infection, whereas leukopenia was related to PICU admission.

A Novel Algorithm With Paired Predictive Indexes to Stratify the Risk Levels of Neonates With Invasive Bacterial Infections: A Multicenter Cohort Study

BACKGROUND

Our aim was to develop a predictive model comprising clinical and laboratory parameters for early identification of full-term neonates with different risks of invasive bacterial infections (IBIs).

METHODS

We conducted a retrospective study including 1053 neonates presenting in 9 tertiary hospitals in China from January 2010 to August 2019. An algorithm with paired predictive indexes (PPIs) for risk stratification of neonatal IBIs was developed. Predictive performance was validated using k-fold cross-validation.

RESULTS

Overall, 166 neonates were diagnosed with IBIs (15.8%). White blood cell count, C-reactive protein level, procalcitonin level, neutrophil percentage, age at admission, neurologic signs, and ill-appearances showed independent associations with IBIs from stepwise regression analysis and combined into 23 PPIs. Using 10-fold cross-validation, a combination of 7 PPIs with the highest predictive performance was picked out to construct an algorithm. Finally, 58.1% (612/1053) patients were classified as low-risk cases. The sensitivity and negative predictive value of the algorithm were 95.3% (95% confidence interval: 91.7-98.3) and 98.7% (95% confidence interval: 97.8-99.6), respectively. An online calculator based on this algorithm was developed for clinical use.

CONCLUSIONS

The new algorithm constructed for this study was a valuable tool to screen neonates with suspected infection. It stratified risk levels of IBIs and had an excellent predictive performance.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Molecular epidemiology and antimicrobial resistance phenotype of paediatric bloodstream infections caused by Gram-negative bacteria

Background

Gram-negative organisms are common causes of bloodstream infection (BSI) during the neonatal period and early childhood. Whilst several large studies have characterised these isolates in adults, equivalent data (particularly incorporating whole genome sequencing) is lacking in the paediatric population.

Methods

We perform an epidemiological and sequencing based analysis of Gram-negative bloodstream infections (327 isolates (296 successfully sequenced) from 287 patients) in children <18 years old between 2008 and 2018 in Oxfordshire, UK.

Results

Here we show that the burden of infection lies predominantly in neonates and that most infections are caused by Escherichia coli, Klebsiella spp. and Enterobacter hormaechei. There is no evidence in our setting that the proportion of antimicrobial resistant isolates is increasing in the paediatric population although we identify some evidence of sub-breakpoint increases in gentamicin resistance. The population structure of E. coli BSI isolates in neonates and children mirrors that in adults with a predominance of STs 131/95/73/69 and the same proportions of O-antigen serotypes. In most cases in our setting there is no evidence of transmission/point-source acquisition and we demonstrate the utility of whole genome sequencing to refute a previously suspected outbreak.

Conclusions

Our findings support continued use of current empirical treatment guidelines and suggest that O-antigen targeted vaccines may have a role in reducing the incidence of neonatal sepsis.

Frequency of serious bacterial infections in young infants with and without viral respiratory infections

BACKGROUND

The goal of our investigation was to describe the incidence of serious bacterial infection (SBI, defined as bacteremia, urinary tract infection (UTI), or meningitis) in young infants with and without documented viral pathogens.

METHODS

This was a retrospective cross-sectional study (1/2016-12/2017) in 3 emergency departments (EDs). Previously healthy 0-60-day-old infants were included if at least respiratory viral testing and a blood culture was obtained. The frequency of SBI, the primary outcome, was compared among infants with/without respiratory viral infections using the Pearson Chi-square test (or Fisher's Exact Test) and unadjusted odds ratios (OR).

RESULTS

The median age of the 597-infant cohort was 32 days (interquartile range: 20-45 days); 42% were female. Eighty-three percent were well appearing in the ED and 72% were admitted. ED triage vitals commonly revealed tachypnea (68%), pyrexia (45%), and tachycardia (28%); hypoxemia (5%) was uncommon. Twenty-eight percent had positive viral testing, most commonly RSV (93/169, 55%), parainfluenza (29, 17%), and influenza A (23, 14%). Eighty-three infants (13.9%) had SBI: 8.4% (n = 50) had UTI alone, 2.8% (n = 17) had bacteremia alone, 1.2% (n = 7) had bacteremia + UTI, 1.0% (n = 6) had bacteremia + meningitis, and 0.5% (n = 3) had meningitis alone. Infants with documented respiratory viral pathogens were less likely to have any SBI (OR: 0.23; 95% CI: 0.11-0.50), UTI (OR 0.22, 95% CI: 0.09-0.56), or bacteremia (OR 0.27, 95% CI: 0.08-0.9) than infants with negative viral testing. There was no difference in meningitis frequency based on viral status (OR: 0.13, 95% CI: 0.008-2.25).

CONCLUSIONS

The frequency of bacteremia and UTI was lower in young infants with respiratory viral infections compared to infants with negative respiratory viral testing.

Infants Younger Than 90 Days Admitted for Late-Onset Sepsis Display a Reduced Abundance of Regulatory T Cells

Objective

To provide epidemiological data of infants < 90 days of age with suspected late-onset sepsis (LOS) and evaluate distinct immunological specificities. We hypothesized that previously healthy infants < 3 months of age with sepsis have a yet undefined immunological predisposition; e.g. differences in lymphocyte subsets including regulatory T cells.

Methods

We performed an exploratory, single center study between January 1^st, 2019 and June 1^st, 2021. Routine diagnostics included conventional culture (blood, cerebrospinal fluid, urine), PCR and inflammatory markers in infants < 90 days of age with suspected sepsis. We additionally analyzed lymphocyte subsets and CD4+ CD25+ forkhead box protein (FoxP3)⁺ Tregs at admission for sepsis workup as compared to age-matched controls.

Results

A convenience sample cohort of n= 51 infants with sepsis workup was enrolled. Invasive bacterial infection (IBI) was diagnosed in 25 (49.0%) patients including two infants with a rhinovirus co-infection and viral infection in 14 (27.5%) neonates. No infectious cause was found in 12 cases. Infants with suspected LOS displayed a decreased abundance of CD4+ FoxP3+ T cells as compared to controls, which was most pronounced in the subgroup of infants with IBI. We also noticed elevated HLA-DR-positive CD3+ cells in infants with LOS and a higher CD4/CD8-ratio in infants with viral infection as compared to healthy controls. Infants with viral infections had a higher number of natural killer cells as compared to infants with IBI.

Conclusion

Our exploratory data support the concept of a potential immaturity state and failed immune tolerance development for young infants with LOS. Future large-scale studies are needed to elucidate pre-sepsis conditions and to target the microbiome-immunity interplay as a potential risk pattern.

Prevalence of Invasive Bacterial Infections in Well-Appearing, Febrile Infants

BACKGROUND AND OBJECTIVES

Data on invasive bacterial infection (IBI), defined as bacteremia and/or bacterial meningitis, in febrile infants aged <60 days old primarily derive from smaller, dated studies conducted at large, university-affiliated medical centers. Our objective with the current study was to determine current prevalence and epidemiology of IBI from a contemporary, national cohort of well-appearing, febrile infants at university-affiliated and community-based hospitals.

PATIENTS AND METHODS

Retrospective review of well-appearing, febrile infants aged 7 to 60 days was performed across 31 community-based and 44 university-affiliated centers from September 2015 to December 2017. Blood and cerebrospinal fluid bacterial culture results were reviewed and categorized by using a priori criteria for pathogenic organisms. Prevalence estimates and subgroup comparisons were made by using descriptive statistics.

RESULTS

A total of 10 618 febrile infants met inclusion criteria; cerebrospinal fluid and blood cultures were tested from 6747 and 10 581 infants, respectively. Overall, meningitis prevalence was 0.4% (95% confidence interval [CI]: 0.2-0.5); bacteremia prevalence was 2.4% (95% CI: 2.1-2.7). Neonates aged 7 to 30 days had significantly higher prevalence of bacteremia, as compared with infants in the second month of life. IBI prevalence did not differ between community-based and university-affiliated hospitals (2.7% [95% CI: 2.3-3.1] vs 2.1% [95% CI: 1.7-2.6]). Escherichia coli and Streptococcus agalactiae were the most commonly identified organisms.

CONCLUSIONS

This contemporary study of well-appearing, febrile infants supports previous epidemiological estimates of IBI prevalence and suggests that the prevalence of IBI may be similar among community-based and university-affiliated hospitals. These results can be used to aid future clinical guidelines and prediction tool development.

Eliminating Lumbar Puncture for Low-Risk Febrile Infants: A Quality Improvement Initiative

BACKGROUND

Bacterial meningitis in low-risk febrile young infants (FYIs) aged >28 days has become increasingly rare. Routine performance of lumbar puncture (LP) in these infants is associated with adverse consequences and may be unnecessary. We modified our clinical practice guideline (CPG) to reduce the number of FYIs 29 to 56 days old who receive LP.

METHODS

This quality improvement project sought to modify a preexisting CPG to diagnose and manage FYIs 0 to 56 days old that eliminated routine performance of LP in children 29 to 56 days old who were considered low-risk for serious bacterial infection. The change was implemented by making adjustments to the online CPG. A statistical process control chart was used to assess the affect of the initiative on our primary outcome of LP rate in this population of FYIs.

RESULTS

Postimplementation of the CPG initiative, 71% of FYIs 29 to 56 days old did not receive LP, compared with 42% preimplementation. This practice change was also associated with fewer hospitalizations, lower median emergency department (ED) length of stay, and fewer 72-hour ED revisits. Over 3 years of sustained practice, 1/713 (0.1%; 95% confidence interval, 0%-0.8%) low-risk FYI returned within 72 hours and was subsequently treated for probable bacterial meningitis, although cerebrospinal fluid culture was negative for bacterial growth.

CONCLUSIONS

A change in CPG reduced the number of LPs performed in febrile infants 29 to 56 days old. This change resulted in fewer LPs, hospitalizations, ED revisits, and a lower ED length of stay for FYIs 29 to 56 days old.

Evaluation and Management of Well-Appearing Febrile Infants 8 to 60 Days Old

This guideline addresses the evaluation and management of well-appearing, term infants, 8 to 60 days of age, with fever ≥38.0°C. Exclusions are noted. After a commissioned evidence-based review by the Agency for Healthcare Research and Quality, an additional extensive and ongoing review of the literature, and supplemental data from published, peer-reviewed studies provided by active investigators, 21 key action statements were derived. For each key action statement, the quality of evidence and benefit-harm relationship were assessed and graded to determine the strength of recommendations. When appropriate, parents' values and preferences should be incorporated as part of shared decision-making. For diagnostic testing, the committee has attempted to develop numbers needed to test, and for antimicrobial administration, the committee provided numbers needed to treat. Three algorithms summarize the recommendations for infants 8 to 21 days of age, 22 to 28 days of age, and 29 to 60 days of age. The recommendations in this guideline do not indicate an exclusive course of treatment or serve as a standard of medical care. Variations, taking into account individual circumstances, may be appropriate.

A retrospective review of serious infections in febrile infants 0–90 days old

Background:

Fever without source in infants is a common clinical problem that accounts for many ambulatory care visits and hospitalisations. Currently, there is no reliable method of identifying those at risk of serious infection (SI).

Objective:

The goal of this study was to determine the incidence and identify the predictors of SI in febrile infants who presented to the emergency department (ED).

Methods:

This was a single-centre retrospective cohort study of children presenting to a Singapore tertiary hospital paediatric unit between 1 July 2018 and 31 December 2018. Children were included if they were aged 0–90 days and presented to the ED with a fever. SI was defined as urinary tract infection (UTI), sepsis, bacteraemia, meningitis (viral and bacterial), enterocolitis, osteomyelitis, abscess or pneumonia.

Results:

Of the 659 infants, 161 (24.4%) were diagnosed with SI. Meningitis (49.7%) was the most common SI, followed by UTI (45.3%), enterocolitis (5.6%), sepsis (3.1%) and bacteraemia (2.5%). Factors significantly associated with SI were aged 29–60 days, male sex, Severity Index Score (SIS) <10, absolute neutrophil counts >10×109/L, C-reactive protein (CRP) >20 mg/L and procalcitonin >0.5 ng/mL. Multivariate analysis entering all these items retained only male sex, SIS <10 and CRP >20.

Conclusion:

Among hospitalised infants aged 0–90 days, the incidence of SI was 24.4%, and invasive bacterial infection was 0.6%. Meningitis was the most common SI followed by UTI. SIS and CRP can be used to predict SI in infants <90 days old.

Prevalence of Bacterial Meningitis Among Febrile Infants Aged 29-60 Days With Positive Urinalysis Results: A Systematic Review and Meta-analysis

IMPORTANCE

Fever in the first months of life remains one of the most common pediatric problems. Urinary tract infections are the most frequent serious bacterial infections in this population. All published guidelines and quality initiatives for febrile young infants recommend lumbar puncture (LP) and cerebrospinal fluid (CSF) testing on the basis of a positive urinalysis result to exclude bacterial meningitis as a cause. For well infants older than 28 days with an abnormal urinalysis result, LP remains controversial.

OBJECTIVE

To assess the prevalence of bacterial meningitis among febrile infants 29 to 60 days of age with a positive urinalysis result to evaluate whether LP is routinely required.

DATA SOURCES

MEDLINE and Embase were searched for articles published from January 1, 2000, to July 25, 2018, with deliberate limitation to recent studies. Before analysis, the search was repeated (October 6, 2019) to ensure that new studies were included.

STUDY SELECTION

Studies that reported on healthy, full-term, well-appearing febrile infants 29 to 60 days of age for whom patient-level data could be ascertained for urinalysis results and meningitis status were included.

DATA EXTRACTION AND SYNTHESIS

Data were extracted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and used the Newcastle-Ottawa Scale to assess bias. Pooled prevalences and odds ratios (ORs) were estimated using random-effect models.

MAIN OUTCOMES AND MEASURES

The primary outcome was the prevalence of culture-proven bacterial meningitis among infants with positive urinalysis results. The secondary outcome was the prevalence of bacterial meningitis, defined by CSF testing or suggestive history at clinical follow-up.

RESULTS

The parent search yielded 3227 records; 48 studies were included (17 distinct data sets of 25 374 infants). The prevalence of culture-proven meningitis was 0.44% (95% CI, 0.25%-0.78%) among 2703 infants with positive urinalysis results compared with 0.50% (95% CI, 0.33%-0.76%) among 10 032 infants with negative urinalysis results (OR, 0.74; 95% CI, 0.39-1.38). The prevalence of bacterial meningitis was 0.25% (95% CI, 0.14%-0.45%) among 4737 infants with meningitis status ascertained by CSF testing or clinical follow-up and 0.28% (95% CI, 0.21%-0.36%) among 20 637 infants with positive and negative urinalysis results (OR, 0.89; 95% CI, 0.48-1.68).

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, the prevalence of bacterial meningitis in well-appearing febrile infants 29 to 60 days of age with positive urinalysis results ranged from 0.25% to 0.44% and was not higher than that in infants with negative urinalysis results. These results suggest that for these infants, the decision to use LP should not be guided by urinalysis results alone.

External Validation of an Invasive Bacterial Infection Score for Young Febrile Infants

OBJECTIVES

The Aronson rule is a point-based clinical decision rule for the identification of febrile infants ≤60 days of age at low risk of invasive bacterial infection (IBI) in the emergency department. This rule uses variables of temperature, age, urinalysis, and absolute neutrophil count. We sought to externally validate this decision rule.

METHODS

We conducted a secondary analysis of a multicenter prospective cohort of febrile infants ≤60 days old presenting to the emergency department between December 2008 and May 2013. Infants were excluded if they had clinical sepsis or chronic conditions or were missing any laboratory components of the Aronson score. Our outcome was IBI (bacteremia and/or bacterial meningitis). We assessed the accuracy of the Aronson rule by reporting metrics of diagnostic accuracy with 95% confidence intervals (CIs) at different point thresholds.

RESULTS

Of 4130 included patients (780 <21 days of age; 2362 boys), 87 (2.1%) had an IBI, including 65 with isolated bacteremia and 22 with meningitis. Using an Aronson cutoff score of 2 resulted in a sensitivity of 93.1% (95% CI 85.6%-97.4%), specificity of 26.6% (95% CI 25.3%-28.0%), and negative predictive value of 99.4% (95% CI 98.8%-99.8%). Six patients with IBI (3 with bacterial meningitis) were misclassified as low risk when using a threshold of 2.

CONCLUSIONS

The Aronson rule demonstrates metrics of diagnostic accuracy that are comparable to the derivation study. Our findings suggest that the rule may be generalizable for the risk stratification of well-appearing febrile infants.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Predictors of serious bacterial infections using serum biomarkers in an infant population aged 0 to 90 days: a prospective cohort study

OBJECTIVE

Young febrile infants represent a vulnerable population at risk for serious bacterial infections (SBI). We aimed to evaluate the diagnostic accuracy of components of the complete blood count in comparison with C-reactive protein (CRP) to predict SBI among febrile infants.

DESIGN AND SETTING

Prospective cohort study conducted in a tertiary emergency department between December 2018 and November 2019.

PATIENTS

We included febrile infants ≤3 months old with complete blood count results. We analysed their white blood cell count (WBC), absolute neutrophil ratio (ANC), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio, mean platelet volume to platelet count ratio, and compared these to the performance of CRP.

MAIN OUTCOME MEASURES

SBIs were defined as urinary tract infection, bacteraemia, bacterial meningitis, sepsis, pneumonia, skin and soft tissue infection, bacterial enteritis, septic arthritis or osteomyelitis.

RESULTS

Of the 187 infants analysed, 54 (28.9%) were diagnosed with SBI. Median values of WBC, ANC, NLR and CRP were significantly higher in infants with SBI: WBC (13.8 vs 11.4×10⁹/L, p=0.004), ANC (6.7 vs 4.1×10⁹/L, p<0.001), NLR (1.3 vs 0.9, p=0.001) and CRP (21.0 vs 2.3 mg/L, p<0.001), compared with those without. CRP had the best discriminatory values for SBI, with area under the curve (AUC) of 0.815 (95% CI 0.747 to 0.883), compared with WBC, ANC and NLR. A predictive model consisting of WBC, ANC and NLR in combination with clinical parameters, had an AUC of 0.814 (95% CI 0.746 to 0.883). There was increased discriminative performance when this predictive model was combined with CRP, (AUC of 0.844, 95% CI 0.782 to 0.906).

CONCLUSION

In young febrile infants, CRP was the best discriminatory biomarker for SBI. WBC, ANC and NLR when used in combination have potential diagnostic utility in this population.

Antimicrobial Resistance Analysis of Clinical Escherichia coli Isolates in Neonatal Ward

Background: Escherichia coli (E. coli) column for one of the most common pathogens causing neonatal infections. The emergence of antibiotic-resistant bacteria is a major cause of treatment failure in infected newborns. The purpose of this study was to describe antibiotic and multidrug resistance of E. coli strains isolated from neonates with infection throughout the years 2009-2011. Methods: The antimicrobial susceptibility testing of E. coli strains to selected antibiotics was assessed using the E-test technique on the Mueller-Hinton agar. The antimicrobial tests included ceftazidime, cefuroxime, cefatriaxone, amoxicillin, amoxicillin-clavulanic acid, cefoperazone- sulbactam, meropenem, gentamicin, ciprofloxacin, and sulfonamides. Results: A total of 100 E. coli strains were isolated from sputum (n = 78), blood (n = 10), cerebrospinal fluid (n = 5), and umbilical discharge (n = 7) samples of hospitalized neonates at the Beijing Children's Hospital. The highest rate of E. coli resistance was found in amoxicillin (85%), followed by cefuroxime (65%), and cefatriaxone (60%), respectively. A total of 6 and 5% of all isolates were only resistant to amoxicillin/clavulanic acid and cefoperazone -sulbactam. The rates of resistance to ceftazidime, gentamicin, ciprofloxacin, and sulfonamides were 31, 20, 33, and 47%, respectively. All isolates were susceptible to meropenem. Approximately 26% of all E. coli isolates were multidrug-resistant. The detection rate of ESBL-Producing E. coli was 55%. Conclusions: Multi-drug-resistant E. coli has become an important and complex problem in clinical treatment, and it is thus essential to monitor E. coli resistance in neonates.

Nephrotoxic medications and acute kidney injury risk factors in the neonatal intensive care unit: clinical challenges for neonatologists and nephrologists

Neonatal acute kidney injury (AKI) is common. Critically ill neonates are at risk for AKI for many reasons including the severity of their underlying illnesses, prematurity, and nephrotoxic medications. In this educational review, we highlight four clinical scenarios in which both the illness itself and the medications indicated for their treatment are risk factors for AKI: sepsis, perinatal asphyxia, patent ductus arteriosus, and necrotizing enterocolitis. We review the available evidence regarding medications commonly used in the neonatal period with known nephrotoxic potential, including gentamicin, acyclovir, indomethacin, vancomycin, piperacillin-tazobactam, and amphotericin. We aim to illustrate the complexity of decision-making involved for both neonatologists and pediatric nephrologists when managing infants with these conditions and advocate for ongoing multidisciplinary collaboration in the development of better AKI surveillance protocols and AKI mitigation strategies to improve care for these vulnerable patients.

Incidence and aetiology of serious viral infections in young febrile infants

AIM

While the incidence and aetiology of serious bacterial infections among febrile infants younger than 90 days old are well studied, those concerning viral infection are not. There are severe life-threatening viral infections requiring immediate intense therapy. The objective of the study is to describe the incidence and aetiology of serious viral infections (SVI) among young febrile infants.

METHODS

A retrospective audit was performed covering all the febrile infants younger than 90 days old admitted to a paediatric emergency department in Japan from 2011 to 2013. SVI was defined as a viral illness that may result in permanent organ dysfunctions or life-threatening complications. Diagnostic investigation consisted of urine and blood culture for all infants, cerebrospinal fluid cultures for infants who do not fulfil the low-risk criteria, rapid antigen tests for several viruses in infants with specific symptoms and blood and/or cerebrospinal fluid polymerase chain reaction of possible viruses for infants with fever without a localising source.

RESULTS

Of 275 cases, 32 and 45 cases were diagnosed as serious viral and bacterial infections, respectively. Intensive care unit admission occurred for three viral and four bacterial infections. Viral aetiology consisted of respiratory syncytial virus (11 cases), aseptic meningitis (9 cases), enterovirus (6 cases), influenza virus (3 cases), rotavirus (2 cases) and herpes simplex virus-1 (1 case). Respiratory (14 cases), central nervous (12 cases) and circulatory (6 cases) systems were affected.

CONCLUSION

SVI was observed in 11.6% of febrile young infants in a paediatric emergency department.

Performance of the Modified Boston and Philadelphia Criteria for Invasive Bacterial Infections

BACKGROUND

The ability of the decades-old Boston and Philadelphia criteria to accurately identify infants at low risk for serious bacterial infections has not been recently reevaluated.

METHODS

We assembled a multicenter cohort of infants 29 to 60 days of age who had cerebrospinal fluid (CSF) and blood cultures obtained. We report the performance of the modified Boston criteria (peripheral white blood cell count [WBC] ≥20 000 cells per mm³, CSF WBC ≥10 cells per mm³, and urinalysis with >10 WBC per high-power field or positive urine dip result) and modified Philadelphia criteria (peripheral WBC ≥15 000 cells per mm³, CSF WBC ≥8 cells per mm³, positive CSF Gram-stain result, and urinalysis with >10 WBC per high-power field or positive urine dip result) for the identification of invasive bacterial infections (IBIs). We defined IBI as bacterial meningitis (growth of pathogenic bacteria from CSF culture) or bacteremia (growth from blood culture).

RESULTS

We applied the modified Boston criteria to 8344 infants and the modified Philadelphia criteria to 8131 infants. The modified Boston criteria identified 133 of the 212 infants with IBI (sensitivity 62.7% [95% confidence interval (CI) 55.9% to 69.3%] and specificity 59.2% [95% CI 58.1% to 60.2%]), and the modified Philadelphia criteria identified 157 of the 219 infants with IBI (sensitivity 71.7% [95% CI 65.2% to 77.6%] and specificity 46.1% [95% CI 45.0% to 47.2%]). The modified Boston and Philadelphia criteria misclassified 17 of 53 (32.1%) and 13 of 56 (23.3%) infants with bacterial meningitis, respectively.

CONCLUSIONS

The modified Boston and Philadelphia criteria misclassified a substantial number of infants 29 to 60 days old with IBI, including those with bacterial meningitis.

Educational Case: Group B Streptococcus Meningitis

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.¹

Community-acquired serious bacterial infections in the first 90 days of life: a revisit in the era of multi-drug-resistant organisms

BACKGROUND

Infants in the first 90 days of life are more prone to develop serious bacterial infections (SBIs). Multi-drug-resistant organisms (MDROs) are emerging as important pathogens causing SBIs. We reviewed the epidemiology of SBIs in infants 0-90 days old and compared the clinical features, laboratory values and final outcome for SBIs due to MDROs vs. non-MDROs.

METHODS

Episodes of culture-proven SBIs (bacteremia, urinary tract infections, or meningitis) with age at onset of 0-90 days during a 7-year period were retrospectively reviewed. Health care-associated infections were excluded. We collected demographics, clinical features, and laboratory and microbiology data. We compared clinical characteristics, laboratory data, microbiologic results and final outcome for SBIs due to MDROs vs. non-MDROs.

RESULTS

Ninety-four episodes (88 patients) including bacteremia (42.6%), urinary tract infections (54.3%) and meningitis (3.1%) were caused by Gram-negative bacteria (67%), and Gram-positive bacteria (33%). Escherichia coli, Klebsiella pneumoniae and GBS were the most common causes. MDROs caused SBIs in 39 patients (44.3%). SBIs due to MDROs were associated with more delay in providing targeted antimicrobial therapy compared to non-MDROs (74.4% vs. 0%, P ≤ 0.001), but no difference in case-fatality rate (12.8% vs. 12.2%, P = 1.0). Clinical features or basic laboratory values were not statistically different between the two groups.

CONCLUSIONS

The bacteriology of SBIs in the first 90 days of life is changing to include more MDROs, which causes more delay in providing targeted antimicrobial therapy. Awareness of the local epidemiology is crucial to ensure appropriate antibiotics are provided in a timely manner.