Evaluation of Lyme serologic quantitative test indexes: High first-tier test index values predict positive second-tier result in standard and modified 2-tier Lyme testing algorithms

OBJECTIVES

In this study, we evaluated the potential utility of reporting a quantitative Lyme serologic test index to improve the utility of results from first-tier Lyme assays.

METHODS

Serum from consecutive samples sent to our laboratory for Lyme testing were tested on 2 commercial first-tier Lyme assays and evaluated to determine the probability of second-tier confirmation based on the serologic index value.

RESULTS

For both assays, we identified an index value above which 100% of samples confirmed on second-tier testing using both standard and modified 2-tier testing algorithms. Lower rates of confirmation were observed for positive or equivocal samples with lower index values.

CONCLUSION

The use of a Lyme test index value may eliminate the need for confirmatory testing on many positive first-tier samples, providing more rapid turnaround time to a definitive result. This practice would also increase efficiency in the clinical laboratory.

Comparative Evaluation of Commercial Test Kits Cleared for Use in Modified Two-Tiered Testing Algorithms for Serodiagnosis of Lyme Disease

BACKGROUND

Modified 2-tiered testing (MTTT) for Lyme disease utilizes automatable, high throughput immunoassays (AHTIs) in both tiers without involving western immunoblots, offering performance and practical advantages over standard 2-tiered testing (STTT; first-tier AHTI followed by immunoglobulin M (IgM) and immunoglobulin G (IgG) western immunoblots). For MTTT, Centers for Disease Control and Prevention recommends using AHTI test kits that have been cleared by Food and Drug Administration (FDA) specifically for this intended use. We evaluated performance of FDA-cleared MTTT commercial test kits from 3 manufacturers by comparing with STTT results.

METHODS

We performed MTTT (total antibody AHTI with reflex to separate IgM and IgG AHTIs) using test kits from Diasorin, Gold Standard Diagnostics (GSD), and Zeus Scientific on 382 excess serum samples submitted to the clinical laboratory for routine Lyme disease serologic testing in July 2018, measuring agreement between MTTT and STTT using the κ statistic.

RESULTS

Overall agreement with STTT was 0.87 (95% confidence interval [CI], .77-.97) using Diasorin assays (almost perfect agreement), 0.80 (95% CI, .68-.93) using GSD assays (substantial agreement) and 0.79 (95% CI, .68-.90) using Zeus assays (substantial agreement). For detection of IgM reactivity, agreement between MTTT and STTT was 0.70 (.51-.90; substantial), 0.63 (95% CI, .44-.82; substantial) and 0.56 (95% CI, .38-.73; moderate), respectively. For detection of IgG reactivity, MTTT/STTT agreement was 0.73 (95% CI,.58-.88), 0.78 (95% CI, .62-.94), and 0.75 (95% CI, .60-.90), respectively (substantial agreement in all cases).

CONCLUSIONS

MTTT results obtained using commercial test kits from 3 different manufacturers had substantial to almost perfect agreement with STTT results overall and moderate to substantial agreement for IgM and IgG detection independently. Commercial MTTT tests can be used broadly for the diagnosis of Lyme disease.

Utility of Synovial Fluid Biomarkers for Culture-Positive Septic Arthritis in a Lyme Disease-Endemic Region

OBJECTIVE

To evaluate the performance of synovial fluid biomarkers to identify children with culture-positive septic arthritis.

METHODS

We identified children 6 months to 18 years old presenting to a single emergency department between 2007 and 2022 undergoing evaluation for septic arthritis defined by having a synovial fluid culture obtained. Our primary outcome was septic arthritis defined by a positive synovial fluid culture. We evaluated the ability of synovial fluid biomarkers to identify children with septic arthritis using area under the receiver operating characteristic curve (AUC) analyses. We measured the sensitivity and specificity of commonly used synovial fluid biomarkers.

RESULTS

We included 796 children, of whom 79 (10%) had septic arthritis. Compared with synovial white blood cell count (AUC, 0.72; 95% confidence interval [CI], 0.65-0.78), absolute neutrophil count (AUC, 0.72; 95% CI, 0.66-0.79; P = 0.09), percent neutrophils (AUC, 0.66; 95% CI, 0.60-0.71; P = 0.12), and glucose (AUC, 0.78; 95% CI, 0.67-0.90; P = 0.33) performed similarly, whereas protein (AUC, 0.52; 95% CI, 0.40-0.63, P = 0.04) had lower diagnostic accuracy. Synovial fluid white blood cell count ≥50,000 cells/μL had a sensitivity of 62.0% (95% CI, 50.4%-72.7%) and a specificity of 67.0% (95% CI, 63.4%-70.4%), whereas a positive synovial fluid Gram stain had a sensitivity of 48.1% (95% CI, 36.5%-59.7%) and specificity of 99.1% (95% CI, 98.1%-99.7%) for septic arthritis.

CONCLUSIONS

None of the routinely available synovial fluid biomarkers had sufficient accuracy to be used in isolation in the identification of children with septic arthritis. New approaches including multivariate clinical prediction rules and novel biomarkers are needed.

Predictors of Invasive Bacterial Infection in Febrile Infants Aged 2 to 6 Months in the Emergency Department

Our goal was to identify predictors of invasive bacterial infection (ie, bacteremia and bacterial meningitis) in febrile infants aged 2-6 months. In our multicenter retrospective cohort, older age and lower temperature identified infants at low risk for invasive bacterial infection who could safely avoid routine testing.

Mapping the distribution of Lyme disease at a mid-Atlantic site in the United States using electronic health data

Lyme disease is a spatially heterogeneous tick-borne infection, with approximately 85% of US cases concentrated in the mid-Atlantic and northeastern states. Surveillance for Lyme disease and its causative agent, including public health case reporting and entomologic surveillance, is necessary to understand its endemic range, but currently used case detection methods have limitations. To evaluate an alternative approach to Lyme disease surveillance, we have performed a geospatial analysis of Lyme disease cases from the Johns Hopkins Health System in Maryland. We used two sources of cases: a) individuals with both a positive test for Lyme disease and a contemporaneous diagnostic code consistent with a Lyme disease-related syndrome; and b) individuals referred for a Lyme disease evaluation who were adjudicated to have Lyme disease. Controls were individuals from the referral cohort judged not to have Lyme disease. Residential address data were available for all cases and controls. We used a hierarchical Bayesian model with a smoothing function for a coordinate location to evaluate the probability of Lyme disease within 100 km of Johns Hopkins Hospital. We found that the probability of Lyme disease was greatest in the north and west of Baltimore, and the local probability that a subject would have Lyme disease varied by as much as 30-fold. Adjustment for demographic and ecological variables partially attenuated the spatial gradient. Our study supports the suitability of electronic medical record data for the retrospective surveillance of Lyme disease.

Impact of the COVID-19 pandemic on pediatric faculty: a report from nine academic institutions

BACKGROUND

The COVID-19 pandemic affected home and work routines, which may exacerbate existing academic professional disparities. Objectives were to describe the impact of the pandemic on pediatric faculty's work productivity, identify groups at risk for widening inequities, and explore mitigation strategies.

METHODS

A cross-sectional study of faculty members was conducted at nine U.S. pediatric departments. Responses were analyzed by demographics, academic rank, and change in home caregiving responsibility.

RESULTS

Of 5791 pediatric faculty members eligible, 1504 (26%) completed the survey. The majority were female (64%), over 40 years old (60%), and assistant professors (47%). Only 7% faculty identified as underrepresented in medicine. Overall 41% reported an increase in caregiving during the pandemic. When comparing clinical, administrative, research, and teaching activities, faculty reported worse 1-year outlook for research activities. Faculty with increased caregiving responsibilities were more likely to report concerns over delayed promotion and less likely to have a favorable outlook regarding clinical and research efforts. Participants identified preferred strategies to mitigate challenges.

CONCLUSIONS

The COVID-19 pandemic negatively impacted pediatric faculty productivity with the greatest effects on those with increased caregiving responsibilities. COVID-19 was particularly disruptive to research outlook. Mitigation strategies are needed to minimize the long-term impacts on academic pediatric careers.

IMPACT

The COVID-19 pandemic most negatively impacted work productivity of academic pediatric faculty with caregiving responsibilities. COVID-19 was particularly disruptive to short-term (1-year) research outlook among pediatric faculty. Faculty identified mitigation strategies to minimize the long-term impacts of the pandemic on academic pediatric career pathways.

Radiographic pneumonia in young febrile infants presenting to the emergency department: secondary analysis of a prospective cohort study

OBJECTIVE

The lack of evidence-based criteria to guide chest radiograph (CXR) use in young febrile infants results in variation in its use with resultant suboptimal quality of care. We sought to describe the features associated with radiographic pneumonias in young febrile infants.

STUDY DESIGN

Secondary analysis of a prospective cohort study in 18 emergency departments (EDs) in the Pediatric Emergency Care Applied Research Network from 2016 to 2019. Febrile (≥38°C) infants aged ≤60 days who received CXRs were included. CXR reports were categorised as 'no', 'possible' or 'definite' pneumonia. We compared demographics, clinical signs and laboratory tests among infants with and without pneumonias.

RESULTS

Of 2612 infants, 568 (21.7%) had CXRs performed; 19 (3.3%) had definite and 34 (6%) had possible pneumonias. Patients with definite (4/19, 21.1%) or possible (11/34, 32.4%) pneumonias more frequently presented with respiratory distress compared with those without (77/515, 15.0%) pneumonias (adjusted OR 2.17; 95% CI 1.04 to 4.51). There were no differences in temperature or HR in infants with and without radiographic pneumonias. The median serum procalcitonin (PCT) level was higher in the definite (0.7 ng/mL (IQR 0.1, 1.5)) vs no pneumonia (0.1 ng/mL (IQR 0.1, 0.3)) groups, as was the median absolute neutrophil count (ANC) (definite, 5.8 K/mcL (IQR 3.9, 6.9) vs no pneumonia, 3.1 K/mcL (IQR 1.9, 5.3)). No infants with pneumonia had bacteraemia. Viral detection was frequent (no pneumonia (309/422, 73.2%), definite pneumonia (11/16, 68.8%), possible pneumonia (25/29, 86.2%)). Respiratory syncytial virus was the predominant pathogen in the pneumonia groups and rhinovirus in infants without pneumonias.

CONCLUSIONS

Radiographic pneumonias were uncommon in febrile infants. Viral detection was common. Pneumonia was associated with respiratory distress, but few other factors. Although ANC and PCT levels were elevated in infants with definite pneumonias, further work is necessary to evaluate the role of blood biomarkers in infant pneumonias.

Rehydration Rates and Outcomes in Overweight Children With Diabetic Ketoacidosis

BACKGROUND AND OBJECTIVES

The Pediatric Emergency Care Applied Research Network Fluid Therapies Under Investigation in Diabetic Ketoacidosis (DKA) (FLUID) Trial found that rapid fluid infusion does not increase the risk of cerebral injury. Concern persists, however, whether fluid rates should be adjusted for overweight or obese patients. We used the FLUID Trial database to evaluate associations between fluid infusion rate and outcomes in these patients.

METHODS

We compared children and youth who were overweight, obese, or normal weight, in regard to protocol adherence, mental status changes, time to DKA resolution, and electrolyte abnormalities. We investigated associations between outcomes and the amount of fluid received in these groups.

RESULTS

Obese children and youth were more likely to receive fluids at rates slower than dictated by protocol. Overweight and obese children and youth in the fast fluid arms, who received fluids per the study protocol based on their measured weight, had similar rates of mental status changes or clinically apparent cerebral injury as those with normal weights. Risk of hypophosphatemia was increased in those receiving larger initial bolus volumes and reduced in those receiving higher rehydration rates. No other metabolic outcomes were associated with rehydration.

CONCLUSIONS

Protocol adherence data in the FLUID Trial suggest that physicians are uncomfortable using weight-based fluid calculations for overweight or obese children. However, higher rates of fluid infusion were not associated with increased risk of mental status changes or cerebral injury, suggesting that physicians should not limit fluid resuscitation in obese children and youth with DKA.

Sensitivity of Two-Tiered Lyme Disease Serology in Children With an Erythema Migrans Lesion

In our prospective cohort of 192 children with a physician-diagnosed erythema migrans (EM) lesion, two-tier Lyme disease serology had higher sensitivity in children with multiple EM lesions (76.8% multiple lesions vs. 38.1% single EM; difference 38.7%, 95% confidence interval 24.8%-50.4%). The diagnosis of cutaneous Lyme disease should be based on careful physical examination rather than laboratory testing.

Clinical and Laboratory Predictors of Dehydration Severity in Children With Diabetic Ketoacidosis

STUDY OBJECTIVE

Our primary objective was to characterize the degree of dehydration in children with diabetic ketoacidosis (DKA) and identify physical examination and biochemical factors associated with dehydration severity. Secondary objectives included describing relationships between dehydration severity and other clinical outcomes.

METHODS

In this cohort study, we analyzed data from 753 children with 811 episodes of DKA in the Pediatric Emergency Care Applied Research Network Fluid Therapies Under Investigation Study, a randomized clinical trial of fluid resuscitation protocols for children with DKA. We used multivariable regression analyses to identify physical examination and biochemical factors associated with dehydration severity, and we described associations between dehydration severity and DKA outcomes.

RESULTS

Mean dehydration was 5.7% (SD 3.6%). Mild (0 to <5%), moderate (5 to <10%), and severe (≥10%) dehydration were observed in 47% (N=379), 42% (N=343), and 11% (N=89) of episodes, respectively. In multivariable analyses, more severe dehydration was associated with new onset of diabetes, higher blood urea nitrogen, lower pH, higher anion gap, and diastolic hypertension. However, there was substantial overlap in these variables between dehydration groups. The mean length of hospital stay was longer for patients with moderate and severe dehydration, both in new onset and established diabetes.

CONCLUSION

Most children with DKA have mild-to-moderate dehydration. Although biochemical measures were more closely associated with the severity of dehydration than clinical assessments, neither were sufficiently predictive to inform rehydration practice.

Biomarkers for Pediatric Bacterial Musculoskeletal Infections in Lyme Disease-Endemic Regions

OBJECTIVES

Bacterial musculoskeletal infections (MSKIs) are challenging to diagnose because of the clinical overlap with other conditions, including Lyme arthritis. We evaluated the performance of blood biomarkers for the diagnosis of MSKIs in Lyme disease-endemic regions.

METHODS

We conducted a secondary analysis of a prospective cohort study of children 1 to 21 years old with monoarthritis presenting to 1 of 8 Pedi Lyme Net emergency departments for evaluation of potential Lyme disease. Our primary outcome was an MSKI, which was defined as septic arthritis, osteomyelitis or pyomyositis. We compared the diagnostic accuracy of routinely available biomarkers (absolute neutrophil count, C-reactive protein, erythrocyte sedimentation rate, and procalcitonin) to white blood cells for the identification of an MSKI using the area under the receiver operating characteristic curve (AUC).

RESULTS

We identified 1423 children with monoarthritis, of which 82 (5.8%) had an MSKI, 405 (28.5%) Lyme arthritis, and 936 (65.8%) other inflammatory arthritis. When compared with white blood cell count (AUC, 0.63; 95% confidence interval [CI], 0.55-0.71), C-reactive protein (0.84; 95% CI, 0.80-0.89; P < .05), procalcitonin (0.82; 95% CI, 0.77-0.88; P < .05), and erythrocyte sedimentation rate (0.77; 95% CI, 0.71-0.82; P < .05) had higher AUCs, whereas absolute neutrophil count (0.67; 95% CI, 0.61-0.74; P < .11) had a similar AUC.

CONCLUSIONS

Commonly available biomarkers can assist in the initial approach to a potential MSKI in a child. However, no single biomarker has high enough accuracy to be used in isolation, especially in Lyme disease-endemic areas.

Relationships among biochemical measures in children with diabetic ketoacidosis

OBJECTIVES

Investigating empirical relationships among laboratory measures in children with diabetic ketoacidosis (DKA) can provide insights into physiological alterations occurring during DKA. We determined whether alterations in laboratory measures during DKA conform to theoretical predictions.

METHODS

We used Pearson correlation statistics and linear regression to investigate correlations between blood glucose, electrolytes, pH and PCO₂ at emergency department presentation in 1,681 pediatric DKA episodes. Among children with repeat DKA episodes, we also assessed correlations between laboratory measures at the first vs. second episode.

RESULTS

pH and bicarbonate levels were strongly correlated (r=0.64), however, pH and PCO₂ were only loosely correlated (r=0.17). Glucose levels were correlated with indicators of dehydration and kidney function (blood urea nitrogen (BUN), r=0.44; creatinine, r=0.42; glucose-corrected sodium, r=0.32). Among children with repeat DKA episodes, PCO₂ levels tended to be similar at the first vs. second episode (r=0.34), although pH levels were only loosely correlated (r=0.19).

CONCLUSIONS

Elevated glucose levels at DKA presentation largely reflect alterations in glomerular filtration rate. pH and PCO₂ are weakly correlated suggesting that respiratory responses to acidosis vary among individuals and may be influenced by pulmonary and central nervous system effects of DKA.

Racial Differences in the Diagnosis of Lyme Disease in Children

Black children with Lyme disease compared with children of other races were less likely to have an erythema migrans lesion diagnosed (adjusted odds ratio, 0.34; 95% confidence interval, .14-.79) but more likely to have a swollen joint (adjusted odds ratio, 3.68; 95% confidence interval, 2.13-6.36) after adjustment for age and local Lyme incidence.

Multiplexed high-definition PCR assay for the diagnosis of tick-borne infections in children

Background

Ixodes scapularis ticks can carry Borrelia species as well as other pathogens that cause human disease. The frequency of tick-borne infections and co-infections in children with suspected Lyme disease is unknown, creating clinical uncertainty about the optimal approach to diagnosis.

Methods

We enrolled children aged 1 to 21 years presenting to one of eight Pedi Lyme Net emergency departments for evaluation of Lyme disease. We selected cases with serologically or clinically diagnosed Lyme disease (erythema migrans or early neurologic disease) matched by symptoms, age, gender and center to control subjects without Lyme disease. We tested whole blood samples collected at the time of diagnosis using a high-definition multiplex polymerase chain reaction (HDPCR) panel to identify 9 bacterial or protozoan pathogens associated with human disease. We compared the frequency of tick-borne co-infections in children with Lyme disease to matched controls.

Results

Of the 612 selected samples, 594 (97.1%) had an interpretable multiplex HDPCR result. We identified the following non-Borrelia tick-borne infections: Anaplasma phagocytophilum (2), Ehrlichia chaffeensis (1) and Babesia microti (12). Children with Lyme disease were more likely to have another tick-borne pathogen identified than matched controls [15/297 (5.1%) Lyme cases vs. 0/297 (0%); difference 5.1% 95% CI 2.7, 8.2%).

Conclusions

Although a substantial minority of children with Lyme disease had another tick-borne pathogen identified, either first-line Lyme disease antibiotics provided adequate treatment or the coinfection was subclinical and did not require specific treatment. Further studies are needed to establish the optimal approach to testing for tick-borne co-infections in children.

Comparative effectiveness and complications of intravenous ceftriaxone compared with oral doxycycline in Lyme meningitis in children: a multicentre prospective cohort study

INTRODUCTION

Lyme disease is the most common vectorborne disease in the Northern hemisphere with more than 400 000 new cases in the USA annually. Lyme meningitis is an uncommon but potentially serious clinical manifestation of Lyme disease. Intravenous ceftriaxone had been the first-line treatment for Lyme meningitis, but is associated with a high rate of complications. Although efficacy and effectiveness (or real-world evidence) data for oral doxycycline are limited, practice guidelines were recently expanded to recommend either oral doxycycline or ceftriaxone as first-line treatments for Lyme meningitis. Our goal is to compare oral doxycycline with intravenous ceftriaxone for the treatment of Lyme meningitis on short-term recovery and long-term quality of life.

METHODS AND ANALYSIS

We are performing a prospective cohort study at 20 US paediatric centres located in diverse geographical range where Lyme disease is endemic. The clinical care team will make all antibiotic treatment decisions for children with Lyme meningitis, as per usual practice. We will follow enrolled children for 6 months to determine time of acute symptom recovery and impact on quality of life.

ETHICS AND DISSEMINATION

Boston Children's Hospital, the single Institutional Review Board (sIRB), has approved the study protocol with the other 19 enrolling sites as well as the Utah data coordinating centre relying on the Boston Children's Hospital sIRB. Once the study is completed, we will publish our findings in a peer-reviewed medical journal.

Cognitive function following diabetic ketoacidosis in young children with type 1 diabetes

INTRODUCTION

Young children with type 1 diabetes (T1D) may be at particularly high risk of cognitive decline following diabetic ketoacidosis (DKA). However, studies of cognitive functioning in T1D typically examine school-age children. The goal of this study was to examine whether a single experience of DKA is associated with lower cognitive functioning in young children. We found that recently diagnosed 3- to 5-year-olds who experienced one DKA episode, regardless of its severity, exhibited lower IQ scores than those with no DKA exposure.

METHODS

We prospectively enrolled 46 3- to 5-year-old children, who presented with DKA at the onset of T1D, in a randomized multi-site clinical trial evaluating intravenous fluid protocols for DKA treatment. DKA was moderate/severe in 22 children and mild in 24 children. Neurocognitive function was assessed once 2-6 months after the DKA episode. A comparison group of 27 children with T1D, but no DKA exposure, was also assessed. Patient groups were matched for age and T1D duration at the time of neurocognitive testing.

RESULTS

Children who experienced DKA, regardless of its severity, exhibited significantly lower IQ scores than children who did not experience DKA, F(2, 70) = 6.26, p = .003, partial η²  = .15. This effect persisted after accounting for socioeconomic status and ethnicity.

CONCLUSIONS

A single DKA episode is associated with lower IQ scores soon after exposure to DKA in young children.

Trends in the Use of Procalcitonin at US Children's Hospital Emergency Departments

OBJECTIVES

Procalcitonin (PCT) was approved by the Food and Drug Administration in 2016. We assessed changes in PCT utilization over time in emergency departments (EDs) at US Children's Hospitals and identified the most common conditions associated with PCT testing.

METHODS

We performed a cross-sectional study of children <18 years of age presenting to 1 of 33 EDs contributing data to the Pediatric Health Information System between 2016 and 2020. We examined trends in PCT utilization during an ED encounter between institutions and over the study period. Using All Patients Refined Diagnosis Related Groups, we identified the most common conditions for which PCT was obtained (overall, and relative to the performance of a complete blood count).

RESULTS

The overall rate of PCT testing increased from 0.2% of all ED visits in 2016 to 1.8% in 2020. Across hospitals, the proportion of ED encounters with PCT obtained ranged from 0.0005% to 4.3% with marked variability in overall use. Among children who had PCT testing performed, the most common diagnoses were fever (10.7%), infections of the upper respiratory tract (9.2%), and pneumonia (5.9%). Relative to the performance of a complete blood count, rates of PCT testing were highest among children with sepsis (28.7%), fever (21.4%), pulmonary edema/respiratory failure (17.3%), and bronchiolitis/respiratory syncytial virus pneumonia (15.6%).

CONCLUSIONS

PCT utilization in the ED has increased over the past 5 years with variation between hospitals. PCT is most frequently obtained for children with respiratory infections and febrile illnesses.

Pyuria in Children with Diabetic Ketoacidosis

Acute kidney injury occurs frequently during pediatric diabetic ketoacidosis (DKA). We reviewed urinalyses from 561 children with DKA; pyuria was detected in 19% overall and in 40% of children with more comprehensive urine testing (≥3 urinalyses) during DKA.

Clinical Characteristics of Children with Cerebral Injury preceding Treatment of Diabetic Ketoacidosis

Previous studies have identified more severe acidosis and higher blood urea nitrogen (BUN) as risk factors for cerebral injury during treatment of diabetic ketoacidosis (DKA) in children; however, cerebral injury also can occur before DKA treatment. We found that lower pH and higher BUN levels also were associated with cerebral injury at presentation.

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.

Empiric antibiotics for children with suspected Lyme disease

In our prospective cohort of children undergoing evaluation for non-cutaneous Lyme disease, 02 (13.9% of those with Lyme disease) were not initially treated with an appropriate antibiotics and 356 (13.3% without Lyme disease) received potentially unnecessary antibiotics. Rapid and accurate diagnostics are needed to further improve initial antibiotic treatment decisions.