A National Quality Improvement Collaborative to Improve Antibiotic Use in Pediatric Infections

BACKGROUND

Nearly 25% of antibiotics prescribed to children are inappropriate or unnecessary, subjecting patients to avoidable adverse medication effects and cost.

METHODS

We conducted a quality improvement initiative across 118 hospitals participating in the American Academy of Pediatrics Value in Inpatient Pediatrics Network 2020 to 2022. We aimed to increase the proportion of children receiving appropriate: (1) empirical, (2) definitive, and (3) duration of antibiotic therapy for community-acquired pneumonia, skin and soft tissue infections, and urinary tract infections to ≥85% by Jan 1, 2022. Sites reviewed encounters of children >60 days old evaluated in the emergency department or hospital. Interventions included monthly audit with feedback, educational webinars, peer coaching, order sets, and a mobile app containing site-specific, antibiogram-based treatment recommendations. Sites submitted 18 months of baseline, 2-months washout, and 10 months intervention data. We performed interrupted time series (analyses for each measure.

RESULTS

Sites reviewed 43 916 encounters (30 799 preintervention, 13 117 post). Overall median [interquartile range] adherence to empirical, definitive, and duration of antibiotic therapy was 67% [65% to 70%]; 74% [72% to 75%] and 61% [58% to 65%], respectively at baseline and was 72% [71% to 72%]; 79% [79% to 80%] and 71% [69% to 73%], respectively, during the intervention period. Interrupted time series revealed a 13% (95% confidence interval: 1% to 26%) intercept change at intervention for empirical therapy and a 1.1% (95% confidence interval: 0.4% to 1.9%) monthly increase in adherence per month for antibiotic duration above baseline rates. Balancing measures of care escalation and revisit or readmission did not increase.

CONCLUSIONS

This multisite collaborative increased appropriate antibiotic use for community-acquired pneumonia, skin and soft tissue infections, and urinary tract infection among diverse hospitals.

Incidence of Pediatric Urinary Tract Infections Before and During the COVID-19 Pandemic

IMPORTANCE

Urinary tract infection (UTI) is common in children, but the population incidence is largely unknown. Controversy surrounds the optimal diagnostic criteria and how to balance the risks of undertreatment and overtreatment. Changes in health care use during the COVID-19 pandemic created a natural experiment to examine health care use and UTI diagnosis and outcomes.

OBJECTIVES

To examine the population incidence of UTI in children and assess the changes of the COVID-19 pandemic regarding UTI diagnoses and measures of UTI severity.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective observational cohort study used US commercial claims data from privately insured patients aged 0 to 17 years from January 1, 2016, to December 31, 2021.

EXPOSURE

Time periods included prepandemic (January 1, 2016, to February 29, 2020), early pandemic (April 1 to June 30, 2020), and midpandemic (July 1, 2020, to December 31, 2021).

MAIN OUTCOMES AND MEASURES

The primary outcome was the incidence of UTI, defined as having a UTI diagnosis code with an accompanying antibiotic prescription. Balancing measures included measures of UTI severity, including hospitalizations and intensive care unit admissions. Trends were evaluated using an interrupted time-series analysis.

RESULTS

The cohort included 13 221 117 enrollees aged 0 to 17 years, with males representing 6 744 250 (51.0%) of the population. The mean incidence of UTI diagnoses was 1.300 (95% CI, 1.296-1.304) UTIs per 100 patient-years. The UTI incidence was 0.86 per 100 patient-years at age 0 to 1 year, 1.58 per 100 patient-years at 2 to 5 years, 1.24 per 100 patient-years at 6 to 11 years, and 1.37 per 100 patient-years at 12 to 17 years, and was higher in females vs males (2.48 [95% CI, 2.46-2.50] vs 0.180 [95% CI, 0.178-0.182] per 100 patient-years). Compared with prepandemic trends, UTIs decreased in the early pandemic: -33.1% (95% CI, -39.4% to -26.1%) for all children and -52.1% (95% CI, -62.1% to -39.5%) in a subgroup of infants aged 60 days or younger. However, all measures of UTI severity decreased or were not significantly different. The UTI incidence returned to near prepandemic rates (-4.3%; 95% CI, -32.0% to 34.6% for all children) after the first 3 months of the pandemic.

CONCLUSIONS AND RELEVANCE

In this cohort study, UTI diagnosis decreased during the early pandemic period without an increase in measures of disease severity, suggesting that reduced overdiagnosis and/or reduced misdiagnosis may be an explanatory factor.

Clinical Course of Children 1 to 24 Months Old With Positive Urine Cultures Without Pyuria

OBJECTIVE

To describe the clinical course of children with positive urine cultures without pyuria who were not given antibiotics initially, identify predictors of subsequent antibiotic treatment, and evaluate the association between subsequent treatment and urinary tract infection (UTI) within 30 days.

METHODS

We conducted a multicenter retrospective cohort study of children 1 to 24 months old who had positive urine cultures without pyuria and who were not started on antibiotics upon presentation to 3 health care systems from 2010 to 2021. Outcomes included clinical status at the time urine cultures resulted, escalation of care (emergency department visit or hospitalization) and subsequent antibiotic treatment within 7 days, and subsequent UTI within 30 days of presentation.

RESULTS

Of 202 included children, 61% were female and median age was 9 months. Of 151 patients with clinical status information when cultures resulted, 107 (70.8%, 95% confidence interval [CI] 62.9-77.9%) were improved. Two of 202 children (1.0%, 95% CI 0.2-4.0%) experienced care escalation. Antibiotics were started in 142 (82.2%) children, and treatment was associated with prior UTI (risk ratio [RR] 1.20, 95% CI 1.15-1.26) and lack of improvement (RR 1.22, 95% CI 1.13-1.33). Subsequent UTI was diagnosed in 2 of 164 (1.2%, 95% CI 0.1-4.3%) treated and 0 of 36 (0%, 95% CI 0-9.7%) untreated children.

CONCLUSIONS

Seventy percent of children with positive urine cultures without pyuria improved before starting antibiotics; however, >80% were ultimately treated. Future research should study the impact of diagnostic stewardship interventions and various urine testing strategies to optimize the management of children evaluated for UTI.retain-->.

Research Methods: Diagnostic Test Characteristics

The goal of a diagnostic test is to provide information on the probability of disease. In this article, we review the principles of diagnostic test characteristics, including sensitivity, specificity, positive and negative predictive value, receiver operating characteristics curves, likelihood ratios, and interval likelihood ratios. We illustrate how interval likelihood ratios optimize the information that can be obtained from test results that can take on >2 values, how they are reflected in the slope of the receiver operating characteristics curve, and how they can be easily calculated from published data.

Prevalence of Urinary Tract Infection, Bacteremia, and Meningitis Among Febrile Infants Aged 8 to 60 Days With SARS-CoV-2

Importance

The prevalence of urinary tract infection (UTI), bacteremia, and bacterial meningitis in febrile infants with SARS-CoV-2 is largely unknown. Knowledge of the prevalence of these bacterial infections among febrile infants with SARS-CoV-2 can inform clinical decision-making.

Objective

To describe the prevalence of UTI, bacteremia, and bacterial meningitis among febrile infants aged 8 to 60 days with SARS-CoV-2 vs without SARS-CoV-2.

Design, Setting, and Participants

This multicenter cross-sectional study was conducted as part of a quality improvement initiative at 106 hospitals in the US and Canada. Participants included full-term, previously healthy, well-appearing infants aged 8 to 60 days without bronchiolitis and with a temperature of at least 38 °C who underwent SARS-CoV-2 testing in the emergency department or hospital between November 1, 2020, and October 31, 2022. Statistical analysis was performed from September 2022 to March 2023.

Exposures

SARS-CoV-2 positivity and, for SARS-CoV-2-positive infants, the presence of normal vs abnormal inflammatory marker (IM) levels.

Main Outcomes and Measures

Outcomes were ascertained by medical record review and included the prevalence of UTI, bacteremia without meningitis, and bacterial meningitis. The proportion of infants who were SARS-CoV-2 positive vs negative was calculated for each infection type, and stratified by age group and normal vs abnormal IMs.

Results

Among 14 402 febrile infants with SARS-CoV-2 testing, 8413 (58.4%) were aged 29 to 60 days; 8143 (56.5%) were male; and 3753 (26.1%) tested positive. Compared with infants who tested negative, a lower proportion of infants who tested positive for SARS-CoV-2 had UTI (0.8% [95% CI, 0.5%-1.1%]) vs 7.6% [95% CI, 7.1%-8.1%]), bacteremia without meningitis (0.2% [95% CI, 0.1%-0.3%] vs 2.1% [95% CI, 1.8%-2.4%]), and bacterial meningitis (<0.1% [95% CI, 0%-0.2%] vs 0.5% [95% CI, 0.4%-0.6%]). Among infants aged 29 to 60 days who tested positive for SARS-CoV-2, 0.4% (95% CI, 0.2%-0.7%) had UTI, less than 0.1% (95% CI, 0%-0.2%) had bacteremia, and less than 0.1% (95% CI, 0%-0.1%) had meningitis. Among SARS-CoV-2-positive infants, a lower proportion of those with normal IMs had bacteremia and/or bacterial meningitis compared with those with abnormal IMs (<0.1% [0%-0.2%] vs 1.8% [0.6%-3.1%]).

Conclusions and Relevance

The prevalence of UTI, bacteremia, and bacterial meningitis was lower for febrile infants who tested positive for SARS-CoV-2, particularly infants aged 29 to 60 days and those with normal IMs. These findings may help inform management of certain febrile infants who test positive for SARS-CoV-2.

A Cross-sectional Study Characterizing Pediatric Temperature Percentiles in Children at Well-Child Visits

BACKGROUND

Temperature measurement plays a central role in determining pediatric patients' disease risk and management. However, current pediatric temperature thresholds may be outdated and not applicable to children.

OBJECTIVE

To characterize pediatric temperature norms and variation by patient characteristics, time of measurement, and thermometer route.

METHODS

In this cross-sectional study, we analyzed 134,641 well-child visits occurring between 2014-2019 at primary care clinics that routinely measured temperature. We performed bivariate and multivariable quantile regressions with clustered standard errors to determine temperature percentiles and variation by age, sex, time of measurement, and thermometer route. We performed sensitivity analyses: 1) using a cohort that excluded visits with infectious diagnoses that could explain temperature aberrations and 2) including clinic as a fixed effect.

RESULTS

The median rectal temperature for visits of infants ≤12 months old was 37.2˚C, which was 0.4˚C higher than the median axillary temperature. The median axillary temperature for children 1-18 years old was 36.7˚C, which was 0.1˚C lower than the median values of all other routes. The 99th percentile for rectal temperatures in infants was 37.8˚C and the 99.9th percentile for axillary temperatures in children was 38.5˚C. Adjusted analyses did not demonstrate clinically significant variation in temperature by sex, age, or time of measurement.

CONCLUSIONS

These updated temperature norms can serve as reference values in clinical practice and should be considered in the context of thermometer route used and the clinical condition being evaluated. Variations in temperature values by sex, age, and time of measurement were not clinically significant.

Trends in Prevalence of Bacterial Infections in Febrile Infants During the COVID-19 Pandemic

OBJECTIVES

Our objective was to describe the prevalence of urinary tract infection (UTI) and invasive bacterial infection (IBI) in febrile infants during the coronavirus disease 2019 pandemic.

METHODS

We conducted a multicenter cross-sectional study that included 97 hospitals in the United States and Canada. We included full-term, well-appearing infants 8 to 60 days old with a temperature of ≥38°C and an emergency department visit or hospitalization at a participating site between November 1, 2020 and March 31, 2022. We used logistic regression to determine trends in the odds of an infant having UTI and IBI by study month and to determine the association of COVID-19 prevalence with the odds of an infant having UTI and IBI.

RESULTS

We included 9112 infants; 603 (6.6%) had UTI, 163 (1.8%) had bacteremia without meningitis, and 43 (0.5%) had bacterial meningitis. UTI prevalence decreased from 11.2% in November 2020 to 3.0% in January 2022. IBI prevalence was highest in February 2021 (6.1%) and decreased to 0.4% in January 2022. There was a significant downward monthly trend for odds of UTI (odds ratio [OR] 0.93; 95% confidence interval [CI]: 0.91-0.94) and IBI (OR 0.90; 95% CI: 0.87-0.93). For every 5% increase in COVID-19 prevalence in the month of presentation, the odds of an infant having UTI (OR 0.97; 95% CI: 0.96-0.98) or bacteremia without meningitis decreased (OR 0.94; 95% CI: 0.88-0.99).

CONCLUSIONS

The prevalence of UTI and IBI in eligible febrile infants decreased to previously published, prepandemic levels by early 2022. Higher monthly COVID-19 prevalence was associated with lower odds of UTI and bacteremia.

Duration of Antibiotic Therapy for Bacterial Meningitis in Young Infants: A Systematic Review

BACKGROUND AND OBJECTIVES

Recommendations for parenteral antibiotic therapy duration in bacterial meningitis in young infants are based predominantly on expert consensus. Prolonged durations are generally provided for proven and suspected meningitis and are associated with considerable costs and risks. The objective of the study was to review the literature on the duration of parenteral antibiotic therapy and outcomes of bacterial meningitis in infants &lt;3 months old.

METHODS

We searched PubMed, Embase, and the Cochrane Library for publications until May 31, 2021. Eligible studies were published in English and included infants &lt;3 months old with bacterial meningitis for which the route and duration of antibiotic therapy and data on at least 1 outcome (relapse rates, mortality, adverse events, duration of hospitalization, or neurologic sequelae) were reported.

RESULTS

Thirty-two studies were included: 1 randomized controlled trial, 25 cohort studies, and 6 case series. The randomized controlled trial found no difference in treatment failure rates between 10 and 14 days of therapy. One cohort study concluded that antibiotic courses &gt;21 days were not associated with improved outcomes as compared with shorter courses. The remaining studies had small sample sizes and/or did not stratify outcomes by therapy duration. Meta-analysis was not possible because of the heterogeneity of the treatments and reported outcomes.

CONCLUSIONS

Rigorous, prospective clinical trial data are lacking to determine the optimal parenteral antibiotic duration in bacterial meningitis in young infants. Given the associated costs and risks, there is a pressing need for high-quality comparative effectiveness research to further study this question.

Improving Efficiency on a Pediatric Hospital Medicine Service With Schedule-Based Family-Centered Rounds

BACKGROUND AND OBJECTIVES

Inconsistencies in the timing and process of family-centered rounds can contribute to inefficiencies in patient care, inconsistent nursing participation, and variable end times. Through the implementation of schedule-based rounds, our aims were to (1) start 90% of rounds encounters within 30 minutes of the scheduled time, (2) increase nursing presence from 79% to >90%, and (3) increase the percentage of rounds completed by 11:20 am from 0% to 80% within 1 year.

METHODS

We used quality improvement methods to implement and evaluate a scheduled rounds process on a pediatric hospital medicine service at a university-affiliated children's hospital. Interventions included customization of an electronic health record-linked scheduling tool, daily schedule management by the senior resident, real-time rounds notification to nurses, improved education on rounding expectations, streamlined rounding workflow, and family notification of rounding time. Data were collected daily and run charts were used to track metrics.

RESULTS

One year after implementation, a median of 96% of rounds encounters occurred within 30 minutes of scheduled rounding time, nursing presence increased from a median of 79% to 94%, and the percentage of rounds completed by 11:20 am increased from a median of 0% to 86%. Rounds end times were later with a higher patient census.

CONCLUSIONS

We improved the efficiency of our rounding workflow and bedside nursing presence through a scheduled rounds process facilitated by an electronic health record-linked scheduling tool.

A National Survey of Outpatient Parenteral Antibiotic Therapy Practices

We conducted a national survey of pediatric infectious diseases (ID) clinicians on outpatient parenteral antibiotic therapy (OPAT) practices and post-discharge ID follow-up. Only 15% of sites required ID consultation for all OPAT. ID division resources for post-discharge care varied. Opportunities exist to increase ID involvement in post-discharge management of serious infections.

Clinical guideline highlights for the hospitalist: Diagnosis and management of acute hematogenous osteomyelitis in children

Clinical practice guideline by the Pediatric Infectious Diseases Society and the Infectious Disease Society of America: 2021 Guideline on Diagnosis and Management of Acute Hematogenous Osteomyelitis in Children RELEASE DATE: August 5, 2021 PRIOR VERSION(S): n/a DEVELOPER: Pediatric Infectious Diseases Society (PIDS) and Infectious Disease Society of America (IDSA) FUNDING SOURCE: PIDS and IDSA TARGET POPULATION: Children with suspected or confirmed acute hematogenous osteomyelitis.

Frequency and Consequences of Routine Temperature Measurement at Well-Child Visits

OBJECTIVES

To determine the (1) frequency and visit characteristics of routine temperature measurement and (2) rates of interventions by temperature measurement practice and the probability of incidental fever detection.

METHODS

In this retrospective cohort study, we analyzed well-child visits between 2014-2019. We performed multivariable regression to characterize visits associated with routine temperature measurement and conducted generalized estimating equations regression to determine adjusted rates of interventions (antibiotic prescription, and diagnostic testing) and vaccine deferral by temperature measurement and fever status, clustered by clinic and patient. Through dual independent chart review, fever (≥100.4°F) was categorized as probable, possible, or unlikely to be incidentally detected.

RESULTS

Temperature measurement occurred at 155 527 of 274 351 (58.9%) well-child visits. Of 24 clinics, 16 measured temperature at >90% of visits ("routine measurement clinics") and 8 at <20% of visits ("occasional measurement clinics"). After adjusting for age, ethnicity, race, and insurance, antibiotic prescription was more common (adjusted odds ratio: 1.21; 95% CI 1.13-1.29), whereas diagnostic testing was less common (adjusted odds ratio: 0.76; 95% CI 0.71-0.82) at routine measurement clinics. Fever was detected at 270 of 155 527 (0.2%) routine measurement clinic visits, 47 (17.4%) of which were classified as probable incidental fever. Antibiotic prescription and diagnostic testing were more common at visits with probable incidental fever than without fever (7.4% vs 1.7%; 14.8% vs 1.2%; P < .001), and vaccines were deferred at 50% such visits.

CONCLUSIONS

Temperature measurement occurs at more than one-half of well-child visits and is a clinic-driven practice. Given the impact on subsequent interventions and vaccine deferral, the harm-benefit profile of this practice warrants consideration.

1148. Duration of Antibiotic Therapy in the Treatment of Bacterial Meningitis in Young Infants: A Systematic Review and Narrative Synthesis

Background

IDSA recommendations of 14-21 days of parenteral therapy for bacterial meningitis are based predominantly on expert consensus. Parenteral durations consistent with these recommendations are sometimes provided even when meningitis is suspected but not confirmed. We aimed to systematically review the literature on duration of parenteral antibiotic therapy and outcomes in bacterial meningitis in infants < 3 months of age.

Methods

We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials for publications up until May 11, 2021. Eligible studies were published in English and included infants < 3 months of age with bacterial meningitis for which route and duration of antibiotic therapy and outcomes were reported. We excluded case reports and infants with birth weight < 1500g, major congenital malformations, or neurosurgical conditions. We assessed bias using published tools specific to study type. A meta-analysis was not conducted due to insufficient data on outcomes by duration of therapy. PROSPERO registration: CRD42020201667.

Results

A total of 2195 studies were identified; 280 were selected for full text review and 32 were included for narrative synthesis. There was 1 randomized-controlled trial (RCT), 25 cohort studies, and 6 case series. The RCT found no difference in treatment failure rates between 10 and 14 days of therapy, but only included 2 cerebrospinal fluid (CSF) culture-positive cases. A single cohort study including only CSF culture-negative cases presented outcomes by duration of therapy and concluded that courses >21 days had no impact on prognosis. Twenty-one studies had data on duration of therapy and outcomes by patient, most with small samples (median 4 patients). No conclusions on efficacy of shortened antibiotic courses could be drawn due to small sample sizes and lack of stratification of outcomes by short versus long courses.

Conclusion

Data on parenteral treatment duration in bacterial meningitis in infants < 3 months are primarily observational, and larger studies rarely report outcomes by duration of therapy. Given the associated risks and costs of prolonged parenteral therapy, there is a pressing need for comparative effectiveness research to determine the optimal parenteral treatment duration.

Disclosures

All Authors: No reported disclosures

Height of fever and invasive bacterial infection

OBJECTIVE

We aimed to evaluate the association of height of fever with invasive bacterial infection (IBI) among febrile infants <=60 days of age.

METHODS

In a secondary analysis of a multicentre case-control study of non-ill-appearing febrile infants <=60 days of age, we compared the maximum temperature (at home or in the emergency department) for infants with and without IBI. We then computed interval likelihood ratios (iLRs) for the diagnosis of IBI at each half-degree Celsius interval.

RESULTS

The median temperature was higher for infants with IBI (38.8°C; IQR 38.4-39.2) compared with those without IBI (38.4°C; IQR 38.2-38.9) (p<0.001). Temperatures 39°C-39.4°C and 39.5°C-39.9°C were associated with a higher likelihood of IBI (iLR 2.49 and 3.40, respectively), although 30.4% of febrile infants with IBI had maximum temperatures <38.5°C.

CONCLUSIONS

Although IBI is more likely with higher temperatures, height of fever alone should not be used for risk stratification of febrile infants.

Management and Outcomes in Children with Third-Generation Cephalosporin-Resistant Urinary Tract Infections

BACKGROUND

Third-generation cephalosporin-resistant urinary tract infections (UTIs) often have limited oral antibiotic options with some children receiving prolonged parenteral courses. Our objectives were to determine predictors of long parenteral therapy and the association between parenteral therapy duration and UTI relapse in children with third-generation cephalosporin-resistant UTIs.

METHODS

We conducted a multisite retrospective cohort study of children <18 years presenting to acute care at 5 children's hospitals and a large managed care organization from 2012 to 2017 with a third-generation cephalosporin-resistant UTI from Escherichia coli or Klebsiella spp. Long parenteral therapy was ≥3 days and short/no parenteral therapy was 0-2 days of concordant parenteral antibiotics. Discordant therapy was antibiotics to which the pathogen was non-susceptible. Relapse was a UTI from the same organism within 30 days.

RESULTS

Of the 482 children included, 81% were female and the median age was 3.3 years (interquartile range: 0.8-8). Fifty-four children (11.2%) received long parenteral therapy (median duration: 7 days). Predictors of long parenteral therapy included age <2 months (adjusted odds ratio [aOR] 67.3; 95% confidence interval [CI]: 16.4-275.7), limited oral antibiotic options (aOR 5.9; 95% CI: 2.8-12.3), and genitourinary abnormalities (aOR 5.4; 95% CI: 1.8-15.9). UTI relapse occurred in 1 of the 54 (1.9%) children treated with long parenteral therapy and in 6 of the 428 (1.5%) children treated with short/no parenteral therapy (P = .57). Of the 105 children treated exclusively with discordant antibiotics, 3 (2.9%, 95% CI: 0.6%-8.1%) experienced UTI relapse.

CONCLUSIONS

Long parenteral therapy was associated with age <2 months, limited oral antibiotic options, and genitourinary abnormalities. UTI relapse was rare and not associated with duration of parenteral therapy. For UTIs with limited oral options, further research is needed on the effectiveness of continued discordant therapy.

Temperature Measurement at Well-Child Visits in the United States

OBJECTIVE

To determine the frequency and predictors of temperature measurement at well-child visits in the US and report rates of interventions associated with visits at which temperature is measured and fever is detected.

STUDY DESIGN

In this cross-sectional study, we analyzed 22 518 sampled well-child visits from the National Ambulatory Medical Care Survey between 2003 and 2015. We estimated the frequency of temperature measurement and performed multivariable regression to identify patient, provider/clinic, and seasonal factors associated with the practice. We described rates of interventions (complete blood count, radiograph, urinalysis, antibiotic prescription, and emergency department/hospital referral) by measurement and fever (temperature ≥100.4 °F, ≥38.0 °C) status.

RESULTS

Temperature was measured in 48.5% (95% CI 45.6-51.4) of well-child visits. Measurement was more common during visits by nonpediatric providers (aOR 2.0, 95% CI 1.6-2.5; reference: pediatricians), in Hispanic (aOR 1.9, 95% CI 1.6-2.3) and Black (aOR 1.5, 95% CI 1.2-1.9; reference: non-Hispanic White) patients, and in patients with government (aOR 2.0, 95% CI 1.7-2.4; reference: private) insurance. Interventions were more commonly pursued when temperature was measured (aOR 1.3, 95% CI 1.1-1.6) and fever was detected (aOR 3.8, 95% CI 1.5-9.4).

CONCLUSIONS

Temperature was measured in nearly one-half of all well-child visits. Interventions were more common when temperature was measured and fever was detected. The value of routine temperature measurement during well-child visits warrants further evaluation.

Characteristics of Afebrile Infants ≤60 Days of Age With Invasive Bacterial Infections

OBJECTIVES

To describe the characteristics and outcomes of afebrile infants ≤60 days old with invasive bacterial infection (IBI).

METHODS

We conducted a secondary analysis of a cross-sectional study of infants ≤60 days old with IBI presenting to the emergency departments (EDs) of 11 children's hospitals from 2011 to 2016. We classified infants as afebrile if there was absence of a temperature ≥38°C at home, at the referring clinic, or in the ED. Bacteremia and bacterial meningitis were defined as pathogenic bacterial growth from a blood and/or cerebrospinal fluid culture.

RESULTS

Of 440 infants with IBI, 78 (18%) were afebrile. Among afebrile infants, 62 (79%) had bacteremia without meningitis and 16 (20%) had bacterial meningitis (10 with concomitant bacteremia). Five infants (6%) died, all with bacteremia. The most common pathogens were Streptococcus agalactiae (35%), Escherichia coli (16%), and Staphylococcus aureus (16%). Sixty infants (77%) had an abnormal triage vital sign (temperature <36°C, heart rate ≥181 beats per minute, or respiratory rate ≥66 breaths per minute) or a physical examination abnormality (ill appearance, full or depressed fontanelle, increased work of breathing, or signs of focal infection). Forty-three infants (55%) had ≥1 of the following laboratory abnormalities: white blood cell count <5000 or >15 000 cells per μL, absolute band count >1500 cells per μl, or positive urinalysis. Presence of an abnormal vital sign, examination finding, or laboratory test result had a sensitivity of 91% (95% confidence interval 82%-96%) for IBI.

CONCLUSIONS

Most afebrile young infants with an IBI had vital sign, examination, or laboratory abnormalities. Future studies should evaluate the predictive ability of these criteria in afebrile infants undergoing evaluation for IBI.

Febrile Infants ≤60 Days Old With Positive Urinalysis Results and Invasive Bacterial Infections

OBJECTIVES

We aimed to describe the clinical and laboratory characteristics of febrile infants ≤60 days old with positive urinalysis results and invasive bacterial infections (IBI).

METHODS

We performed a planned secondary analysis of a retrospective cohort study of febrile infants ≤60 days old with IBI who presented to 11 emergency departments from July 1, 2011, to June 30, 2016. For this subanalysis, we included infants with IBI and positive urinalysis results. We analyzed the sensitivity of high-risk past medical history (PMH) (prematurity, chronic medical condition, or recent antimicrobial receipt), ill appearance, and/or abnormal white blood cell (WBC) count (<5000 or >15 000 cells/μL) for identification of IBI.

RESULTS

Of 148 febrile infants with positive urinalysis results and IBI, 134 (90.5%) had bacteremia without meningitis and 14 (9.5%) had bacterial meningitis (11 with concomitant bacteremia). Thirty-five infants (23.6%) with positive urinalysis results and IBI did not have urinary tract infections. The presence of high-risk PMH, ill appearance, and/or abnormal WBC count had a sensitivity of 53.4% (95% confidence interval: 45.0-61.6) for identification of IBI. Of the 14 infants with positive urinalysis results and concomitant bacterial meningitis, 7 were 29 to 60 days old. Six of these 7 infants were ill-appearing or had an abnormal WBC count. The other infant had bacteremia with cerebrospinal fluid pleocytosis after antimicrobial pretreatment and was treated for meningitis.

CONCLUSIONS

The sensitivity of high-risk PMH, ill appearance, and/or abnormal WBC count is suboptimal for identifying febrile infants with positive urinalysis results at low risk for IBI. Most infants with positive urinalysis results and bacterial meningitis are ≤28 days old, ill-appearing, or have an abnormal WBC count.

Diagnosis and Management of UTI in Febrile Infants Age 0-2 Months: Applicability of the AAP Guideline

Urinary tract infections (UTIs) are the most common bacterial infection in young infants. The American Academy of Pediatrics' (AAP) clinical practice guideline for UTIs focuses on febrile children age 2-24 months, with no guideline for infants <2 months of age, an age group commonly encountered by pediatric hospitalists. In this review, we assess the applicability of the AAP UTI Guideline's action statements for previously healthy, febrile infants <2 months of age. We also discuss additional considerations in this age group, including concurrent bacteremia and routine testing for meningitis.

Clinical Response to Discordant Therapy in Third-Generation Cephalosporin-Resistant UTIs

OBJECTIVES

To describe the initial clinical response and care escalation needs for children with urinary tract infections (UTIs) resistant to third-generation cephalosporins while on discordant antibiotics.

METHODS

We performed a retrospective study of children <18 years old presenting to an acute care setting of 5 children's hospitals and a large managed care organization from 2012 to 2017 with third-generation cephalosporin-resistant UTIs (defined as the growth of ≥50 000 colony-forming units per mL of Escherichia coli or Klebsiella spp. nonsusceptible to ceftriaxone with a positive urinalysis). We included children started on discordant antibiotics who had follow-up when culture susceptibilities resulted. Outcomes were escalation of care (emergency department visit, hospital admission, or ICU transfer while on discordant therapy) and clinical response at follow-up (classified as improved or not improved).

RESULTS

Of the 316 children included, 78% were girls and the median age was 2.4 years (interquartile range 0.6-6.5). Children were evaluated in the emergency department (56%) or clinic (43%), and 90% were started on a cephalosporin. A total of 7 of 316 children (2.2%; 95% confidence interval 0.8%-4.5%) experienced escalation of care. For the 230 children (73%) with clinical response recorded, 192 of 230 (83.5%; 95% confidence interval 78.0%-88.0%) experienced clinical improvement. In children with repeat urine testing while on discordant therapy, pyuria improved or resolved in 16 of 19 (84%) and urine cultures sterilized in 11 of 17 (65%).

CONCLUSIONS

Most children with third-generation cephalosporin-resistant UTIs started on discordant antibiotics experienced initial clinical improvement, and few required escalation of care. Our findings suggest that narrow-spectrum empiric therapy is appropriate while awaiting final urine culture results.

Clinical Guideline Highlights for the Hospitalist: Diagnosis and Management of Measles

GUIDELINE TITLE: (1) Measles (Rubeola): For Healthcare Professionals and (2) Interim Infection Prevention and Control Recommendations for Measles in Healthcare Settings RELEASE DATE: (1) February 5, 2018, and (2) July 2019 PRIOR VERSION(S): n/a DEVELOPER: Centers for Disease Control and Prevention (CDC) FUNDING SOURCE: CDC TARGET POPULATION: Children and adults with suspected or confirmed measles.

Cerebrospinal Fluid Profiles of Infants ≤60 Days of Age With Bacterial Meningitis

OBJECTIVES

We aimed to describe the cerebrospinal fluid (CSF) profiles of infants ≤60 days old with bacterial meningitis and the characteristics of infants with bacterial meningitis who did not have CSF abnormalities.

METHODS

We included infants ≤60 days old with culture-positive bacterial meningitis who were evaluated in the emergency departments of 11 children's hospitals between July 1, 2011, and June 30, 2016. From medical records, we abstracted clinical and laboratory data. For infants with traumatic lumbar punctures (CSF red blood cell count of ≥10 000 cells per mm³), we used a red blood cell count/white blood cell (WBC) count correction factor of 1000:1 to determine the corrected CSF WBC count. We calculated the sensitivity for bacterial meningitis of a CSF Gram-stain and corrected CSF pleocytosis (≥16 WBCs per mm³ for infants ≤28 days old and ≥10 WBCs per mm³ for infants 29-60 days old).

RESULTS

Among 66 infants with bacterial meningitis, the sensitivity of a CSF Gram-stain was 71.9% (95% confidence interval [CI]: 59.2-82.4), and the sensitivity of corrected CSF pleocytosis was 80.3% (95% CI: 68.7-89.1). The sensitivity of combining positive Gram-stain results with corrected CSF pleocytosis was 86.4% (95% CI: 75.7-93.6). Of 9 infants with meningitis who had a negative Gram-stain result and no corrected CSF pleocytosis, 8 (88.9%) had either an abnormal peripheral WBC count (>15 000 or <5000 cells per μL) or bandemia >10%.

CONCLUSIONS

Most infants ≤60 days old with bacterial meningitis have CSF pleocytosis or a positive Gram-stain result. Infants with no CSF pleocytosis and a negative Gram-stain result are unlikely to have bacterial meningitis in the absence of other laboratory abnormalities.

Testing for Meningitis in Febrile Well-Appearing Young Infants With a Positive Urinalysis

BACKGROUND AND OBJECTIVES

To determine factors associated with cerebrospinal fluid (CSF) testing in febrile young infants with a positive urinalysis and assess the probability of delayed diagnosis of bacterial meningitis in infants treated for urinary tract infection (UTI) without CSF testing.

METHODS

We performed a retrospective cohort study using data from the Reducing Excessive Variability in Infant Sepsis Evaluation quality improvement project. A total of 20 570 well-appearing febrile infants 7 to 60 days old presenting to 124 hospitals from 2015 to 2017 were included. A mixed-effects logistic regression was conducted to determine factors associated with CSF testing. Delayed meningitis was defined as a new diagnosis of bacterial meningitis within 7 days of discharge.

RESULTS

Overall, 3572 infants had a positive urinalysis; 2511 (70.3%) underwent CSF testing. There was wide variation by site, with CSF testing rates ranging from 64% to 100% for infants 7 to 30 days old and 10% to 100% for infants 31 to 60 days old. Factors associated with CSF testing included: age 7 to 30 days (adjusted odds ratio [aOR]: 4.6; 95% confidence interval [CI]: 3.8-5.5), abnormal inflammatory markers (aOR: 2.2; 95% CI: 1.8-2.5), and site volume >300 febrile infants per year (aOR: 1.8; 95% CI: 1.2-2.6). Among 505 infants treated for UTI without CSF testing, there were 0 (95% CI: 0%-0.6%) cases of delayed meningitis.

CONCLUSIONS

There was wide variation in CSF testing in febrile infants with a positive urinalysis. Among infants treated for UTI without CSF testing (mostly 31 to 60-day-old infants), there were no cases of delayed meningitis within 7 days of discharge, suggesting that routine CSF testing of infants 31 to 60 days old with a positive urinalysis may not be necessary.

Parenteral Antibiotic Therapy Duration in Young Infants With Bacteremic Urinary Tract Infections

OBJECTIVES

To determine the association between parenteral antibiotic duration and outcomes in infants ≤60 days old with bacteremic urinary tract infection (UTI).

METHODS

This multicenter retrospective cohort study included infants ≤60 days old who had concomitant growth of a pathogen in blood and urine cultures at 11 children's hospitals between 2011 and 2016. Short-course parenteral antibiotic duration was defined as ≤7 days, and long-course parenteral antibiotic duration was defined as >7 days. Propensity scores, calculated using patient characteristics, were used to determine the likelihood of receiving long-course parenteral antibiotics. We conducted inverse probability weighting to achieve covariate balance and applied marginal structural models to the weighted population to examine the association between parenteral antibiotic duration and outcomes (30-day UTI recurrence, 30-day all-cause reutilization, and length of stay).

RESULTS

Among 115 infants with bacteremic UTI, 58 (50%) infants received short-course parenteral antibiotics. Infants who received long-course parenteral antibiotics were more likely to be ill appearing and have growth of a non-Escherichia coli organism. There was no difference in adjusted 30-day UTI recurrence between the long- and short-course groups (adjusted risk difference: 3%; 95% confidence interval: -5.8 to 12.7) or 30-day all-cause reutilization (risk difference: 3%; 95% confidence interval: -14.5 to 20.6).

CONCLUSIONS

Young infants with bacteremic UTI who received ≤7 days of parenteral antibiotics did not have more frequent recurrent UTIs or hospital reutilization compared with infants who received long-course therapy. Short-course parenteral therapy with early conversion to oral antibiotics may be considered in this population.

A Prediction Model to Identify Febrile Infants ≤60 Days at Low Risk of Invasive Bacterial Infection

OBJECTIVES

To derive and internally validate a prediction model for the identification of febrile infants ≤60 days old at low probability of invasive bacterial infection (IBI).

METHODS

We conducted a case-control study of febrile infants ≤60 days old who presented to the emergency departments of 11 hospitals between July 1, 2011 and June 30, 2016. Infants with IBI, defined by growth of a pathogen in blood (bacteremia) and/or cerebrospinal fluid (bacterial meningitis), were matched by hospital and date of visit to 2 control patients without IBI. Ill-appearing infants and those with complex chronic conditions were excluded. Predictors of IBI were identified with multiple logistic regression and internally validated with 10-fold cross-validation, and an IBI score was calculated.

RESULTS

We included 181 infants with IBI (155 [85.6%] with bacteremia without meningitis and 26 [14.4%] with bacterial meningitis) and 362 control patients. Twenty-three infants with IBI (12.7%) and 138 control patients (38.1%) had fever by history only. Four predictors of IBI were identified (area under the curve 0.83 [95% confidence interval (CI): 0.79-0.86]) and incorporated into an IBI score: age <21 days (1 point), highest temperature recorded in the emergency department 38.0-38.4°C (2 points) or ≥38.5°C (4 points), absolute neutrophil count ≥5185 cells per μL (2 points), and abnormal urinalysis results (3 points). The sensitivity and specificity of a score ≥2 were 98.8% (95% CI: 95.7%-99.9%) and 31.3% (95% CI: 26.3%-36.6%), respectively. All 26 infants with meningitis had scores ≥2.

CONCLUSIONS

Infants ≤60 days old with fever by history only, a normal urinalysis result, and an absolute neutrophil count <5185 cells per μL have a low probability of IBI.

Factors Associated with Adverse Outcomes among Febrile Young Infants with Invasive Bacterial Infections

OBJECTIVE

To determine factors associated with adverse outcomes among febrile young infants with invasive bacterial infections (IBIs) (ie, bacteremia and/or bacterial meningitis).

STUDY DESIGN

Multicenter, retrospective cohort study (July 2011-June 2016) of febrile infants ≤60 days of age with pathogenic bacterial growth in blood and/or cerebrospinal fluid. Subjects were identified by query of local microbiology laboratory and/or electronic medical record systems, and clinical data were extracted by medical record review. Mixed-effect logistic regression was employed to determine clinical factors associated with 30-day adverse outcomes, which were defined as death, neurologic sequelae, mechanical ventilation, or vasoactive medication receipt.

RESULTS

Three hundred fifty infants met inclusion criteria; 279 (79.7%) with bacteremia without meningitis and 71 (20.3%) with bacterial meningitis. Forty-two (12.0%) infants had a 30-day adverse outcome: 29 of 71 (40.8%) with bacterial meningitis vs 13 of 279 (4.7%) with bacteremia without meningitis (36.2% difference, 95% CI 25.1%-48.0%; P < .001). On adjusted analysis, bacterial meningitis (aOR 16.3, 95% CI 6.5-41.0; P < .001), prematurity (aOR 7.1, 95% CI 2.6-19.7; P < .001), and ill appearance (aOR 3.8, 95% CI 1.6-9.1; P = .002) were associated with adverse outcomes. Among infants who were born at term, not ill appearing, and had bacteremia without meningitis, only 2 of 184 (1.1%) had adverse outcomes, and there were no deaths.

CONCLUSIONS

Among febrile infants ≤60 days old with IBI, prematurity, ill appearance, and bacterial meningitis (vs bacteremia without meningitis) were associated with adverse outcomes. These factors can inform clinical decision-making for febrile young infants with IBI.

Risk Stratification of Febrile Infants ≤60 Days Old Without Routine Lumbar Puncture

: media-1vid110.1542/5840460609001PEDS-VA_2018-1879Video Abstract OBJECTIVES: To evaluate the Rochester and modified Philadelphia criteria for the risk stratification of febrile infants with invasive bacterial infection (IBI) who do not appear ill without routine cerebrospinal fluid (CSF) testing.

METHODS

We performed a case-control study of febrile infants ≤60 days old presenting to 1 of 9 emergency departments from 2011 to 2016. For each infant with IBI (defined as a blood [bacteremia] and/or CSF [bacterial meningitis] culture with growth of a pathogen), controls without IBI were matched by site and date of visit. Infants were excluded if they appeared ill or had a complex chronic condition or if data for any component of the Rochester or modified Philadelphia criteria were missing.

RESULTS

Overall, 135 infants with IBI (118 [87.4%] with bacteremia without meningitis and 17 [12.6%] with bacterial meningitis) and 249 controls were included. The sensitivity of the modified Philadelphia criteria was higher than that of the Rochester criteria (91.9% vs 81.5%; P = .01), but the specificity was lower (34.5% vs 59.8%; P < .001). Among 67 infants >28 days old with IBI, the sensitivity of both criteria was 83.6%; none of the 11 low-risk infants had bacterial meningitis. Of 68 infants ≤28 days old with IBI, 14 (20.6%) were low risk per the Rochester criteria, and 2 had meningitis.

CONCLUSIONS

The modified Philadelphia criteria had high sensitivity for IBI without routine CSF testing, and all infants >28 days old with bacterial meningitis were classified as high risk. Because some infants with bacteremia were classified as low risk, infants discharged from the emergency department without CSF testing require close follow-up.

Epidemiology and Etiology of Invasive Bacterial Infection in Infants ≤60 Days Old Treated in Emergency Departments

OBJECTIVES

To help guide empiric treatment of infants ≤60 days old with suspected invasive bacterial infection by describing pathogens and their antimicrobial susceptibilities.

STUDY DESIGN

Cross-sectional study of infants ≤60 days old with invasive bacterial infection (bacteremia and/or bacterial meningitis) evaluated in the emergency departments of 11 children's hospitals between July 1, 2011 and June 30, 2016. Each site's microbiology laboratory database or electronic medical record system was queried to identify infants from whom a bacterial pathogen was isolated from either blood or cerebrospinal fluid. Medical records of these infants were reviewed to confirm the presence of a pathogen and to obtain demographic, clinical, and laboratory data.

RESULTS

Of the 442 infants with invasive bacterial infection, 353 (79.9%) had bacteremia without meningitis, 64 (14.5%) had bacterial meningitis with bacteremia, and 25 (5.7%) had bacterial meningitis without bacteremia. The peak number of cases of invasive bacterial infection occurred in the second week of life; 364 (82.4%) infants were febrile. Group B streptococcus was the most common pathogen identified (36.7%), followed by Escherichia coli (30.8%), Staphylococcus aureus (9.7%), and Enterococcus spp (6.6%). Overall, 96.8% of pathogens were susceptible to ampicillin plus a third-generation cephalosporin, 96.0% to ampicillin plus gentamicin, and 89.2% to third-generation cephalosporins alone.

CONCLUSIONS

For most infants ≤60 days old evaluated in a pediatric emergency department for suspected invasive bacterial infection, the combination of ampicillin plus either gentamicin or a third-generation cephalosporin is an appropriate empiric antimicrobial treatment regimen. Of the pathogens isolated from infants with invasive bacterial infection, 11% were resistant to third-generation cephalosporins alone.

Time to Pathogen Detection for Non-ill Versus Ill-Appearing Infants ≤60 Days Old With Bacteremia and Meningitis

OBJECTIVES

We sought to determine the time to pathogen detection in blood and cerebrospinal fluid (CSF) for infants ≤60 days old with bacteremia and/or bacterial meningitis and to explore whether time to pathogen detection differed for non-ill-appearing and ill-appearing infants.

METHODS

We included infants ≤60 days old with bacteremia and/or bacterial meningitis evaluated in the emergency departments of 10 children's hospitals between July 1, 2011, and June 30, 2016. The microbiology laboratories at each site were queried to identify infants in whom a bacterial pathogen was isolated from blood and/or CSF. Medical records were then reviewed to confirm the presence of a pathogen and to extract demographic characteristics, clinical appearance, and the time to pathogen detection.

RESULTS

Among 360 infants with bacteremia, 316 (87.8%) pathogens were detected within 24 hours and 343 (95.3%) within 36 hours. A lower proportion of non-ill-appearing infants with bacteremia had a pathogen detected on blood culture within 24 hours compared with ill-appearing infants (85.0% vs 92.9%, respectively; P = .03). Among 62 infants with bacterial meningitis, 55 (88.7%) pathogens were detected within 24 hours and 59 (95.2%) were detected within 36 hours, with no difference based on ill appearance.

CONCLUSIONS

Among infants ≤60 days old with bacteremia and/or bacterial meningitis, pathogens were commonly identified from blood or CSF within 24 and 36 hours. However, clinicians must weigh the potential for missed bacteremia in non-ill-appearing infants discharged within 24 hours against the overall low prevalence of infection.

Risk factors for possible serious bacterial infection in a rural cohort of young infants in central India

Background

Possible serious bacterial infection (PBSI) is a major cause of neonatal mortality worldwide. We studied risk factors for PSBI in a large rural population in central India where facility deliveries have increased as a result of a government financial assistance program.

Methods

We studied 37,379 pregnant women and their singleton live born infants with birth weight ≥ 1.5 kg from 20 rural primary health centers around Nagpur, India, using data from the 2010–13 population-based Maternal and Newborn Health Registry supported by NICHD’s Global Network for Women’s and Children’s Health Research. Factors associated with PSBI were identified using multivariable Poisson regression.

Results

Two thousand one hundred twenty-three infants (6 %) had PSBI. Risk factors for PSBI included nulliparity (RR 1.13, 95 % CI 1.03–1.23), parity > 2 (RR 1.30, 95 % CI 1.07–1.57) compared to parity 1–2, first antenatal care visit in the 2^nd/3^rd trimester (RR 1.46, 95 % CI 1.08–1.98) compared to 1^st trimester, administration of antenatal corticosteroids (RR 2.04, 95 % CI 1.60–2.61), low birth weight (RR 3.10, 95 % CI 2.17–4.42), male sex (RR 1.20, 95 % CI 1.10–1.31) and lack of early initiation of breastfeeding (RR 3.87, 95 % CI 2.69–5.58).

Conclusion

Infants who are low birth weight, born to mothers who present late to antenatal care or receive antenatal corticosteroids, or born to nulliparous women or those with a parity > 2, could be targeted for interventions before and after delivery to improve early recognition of signs and symptoms of PSBI and prompt referral. There also appears to be a need for a renewed focus on promoting early initiation of breastfeeding following delivery in facilities.

Trial registration

This trial is registered at ClinicalTrials.gov (NCT01073475).

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3688-3) contains supplementary material, which is available to authorized users.

Trends in the incidence of possible severe bacterial infection and case fatality rates in rural communities in Sub-Saharan Africa, South Asia and Latin America, 2010-2013: a multicenter prospective cohort study

Background

Possible severe bacterial infections (pSBI) continue to be a leading cause of global neonatal mortality annually. With the recent publications of simplified antibiotic regimens for treatment of pSBI where referral is not possible, it is important to know how and where to target these regimens, but data on the incidence and outcomes of pSBI are limited.

Methods

We used data prospectively collected at 7 rural community-based sites in 6 low and middle income countries participating in the NICHD Global Network’s Maternal and Newborn Health Registry, between January 1, 2010 and December 31, 2013. Participants included pregnant women and their live born neonates followed for 6 weeks after delivery and assessed for maternal and infant outcomes.

Results

In a cohort of 248,539 infants born alive between 2010 and 2013, 32,088 (13 %) neonates met symptomatic criteria for pSBI. The incidence of pSBI during the first 6 weeks of life varied 10 fold from 3 % (Zambia) to 36 % (Pakistan), and overall case fatality rates varied 8 fold from 5 % (Kenya) to 42 % (Zambia). Significant variations in incidence of pSBI during the study period, with proportions decreasing in 3 sites (Argentina, Kenya and Nagpur, India), remaining stable in 3 sites (Zambia, Guatemala, Belgaum, India) and increasing in 1 site (Pakistan), cannot be explained solely by changing rates of facility deliveries. Case fatality rates did not vary over time.

Conclusions

In a prospective population based registry with trained data collectors, there were wide variations in the incidence and case fatality of pSBI in rural communities and in trends over time. Regardless of these variations, the burden of pSBI is still high and strategies to implement timely diagnosis and treatment are still urgently needed to reduce neonatal mortality.

Trial registration

The study was registered at ClinicalTrials.gov (NCT01073475).

Concomitant inhibition of Janus kinase 3 and calcineurin-dependent signaling pathways synergistically prolongs the survival of rat heart allografts

The cytoplasmic localized Janus tyrosine kinase 3 (Jak3) is activated by multiple cytokines, including IL-2, IL-4, and IL-7, through engagement of the IL-2R common gamma-chain. Genetic inactivation of Jak3 is manifested as SCID in humans and mice. These findings have suggested that Jak3 represents a pharmacological target to control certain lymphoid-derived diseases. Using the rat T cell line Nb2-11c, we document that tyrphostin AG-490 blocked in vitro IL-2-induced cell proliferation (IC(50) approximately 20 microM), Jak3 autophosphorylation, and activation of its key substrates, Stat5a and Stat5b, as measured by tyrosine/serine phosphorylation analysis and DNA-binding experiments. To test the notion that inhibition of Jak3 provides immunosuppressive potential, a 7-day course of i.v. therapy with 5-20 mg/kg AG-490 was used to inhibit rejection of heterotopically transplanted Lewis (RT1(l)) heart allografts in ACI (RT1(a)) recipients. In this study, we report that AG-490 significantly prolonged allograft survival, but also acted synergistically when used in combination with the signal 1 inhibitor cyclosporin A, but not the signal 3 inhibitor, rapamycin. Finally, AG-490 treatment reduced graft infiltration of mononuclear cells and Stat5a/b DNA binding of ex vivo IL-2-stimulated graft infiltrating of mononuclear cells, but failed to affect IL2R alpha expression, as judged by RNase protection assays. Thus, inhibition of Jak3 prolongs allograft survival and also potentiates the immunosuppressive effects of cyclosporin A, but not rapamycin.

ICAM-1 antisense oligodeoxynucleotide improves islet allograft survival and function

Expression of intercellular adhesion molecule-1 (ICAM-1) and its ligand, leukocyte function antigen-1 (LFA-1), after pancreatic islet transplantation may affect both nonspecific and alloantigen-specific phases of graft destruction. We examined the effects of ICAM-1/LFA-1 blockade on the survival of islet allografts. Fresh C57BL/10 (H2h) pancreatic islets were transplanted under the renal subcapsular space (KC) or embolized into the liver after portal vein (PV) injection to C3H (H2k) mice. Recipients remained untreated or were treated for 7 days by i.p. administration of: ICAM-1 antisense phosphorothioate oligodeoxynucleotide (oligo) alone; anti-1CAM-1 (alphaICAM-1) monoclonal antibody (mAb) alone: alphaLFA-1 mAb alone; ICAM-1 oligo/alphaLFA mAb combination; alphaICAM-1 mAb/alphaLFA-1 mAb combination; or control oligo IP-8997 or IP-1082. In some experiments, donors were pretreated with ICAM-1 oligo. Inhibition of single ligand with 5.0 mg/kg ICAM-1 oligo (25.1 +/- 10.3), 100 microg/daily alphaICAM-1 mAb (24.2 +/- 8.0 days), or 50 microg/daily alphaLFA-1 mAb (42.8 +/- 25.9 days) prolonged the survivals of KC islet allografts in comparison with untreated controls (11.9 +/- 1.0 days; all p < 0.01). However, dual ICAM-1/LFA-1 blockade with either ICAM-1 oligo/alphaLFA-1 mAb (78.3 +/- 16.5 days) or (alphaICAM-1 mAb/aLFA-1 mAb (65.2 +/- 31.3 days) was the most effective therapy. Although pretreatment of donors with ICAM-1 oligo alone was ineffective (12.2 +/- 0.8 days; NS), a combination of donor pretreatment and recipient treatment started 1 day prior to grafting with ICAM-1 oligo (39.2 +/- 14.0 days) was more effective than the recipient treatment alone (24.6 +/- 8.8 days). Furthermore, ICAM-1/LFA-1 blockade improved islet function as evaluated by glucose tolerance test, and decreased inflammation in comparison with untreated controls. Similar in vivo results were obtained following PV administration of islet allografts. Thus, ICAM-1/LFA-1 blockade prolongs the survival of pancreatic islet allografts and improves their early function.

Inhibition of C-raf expression by antisense oligonucleotides extends heart allograft survival in rats

BACKGROUND

C-raf is a well-characterized serine/ threonine (Ser/Thr) protein kinase that is involved in the transduction of multiple signals of T cells. We demonstrate that the inhibition of C-raf mRNA expression prolongs heart allograft survival.

METHODS

Three 20-mer C-raf antisense oligonucleotides, each with identical sequences, were synthesized with different chemical modifications: one as a uniform phosphorothioate oligodeoxynucleotide (PS oligo), a second with a PS backbone and 2'-methoxyethyl (ME) substitutions at the 2'-sugar positions in the first and last five nucleotides, and a third with a mixed PS and phosphodiester (PD) backbone and ME modifications on the first and last five nucleotides.

RESULTS

Both ME-modified C-raf antisense oligos were at least 5-fold more effective than the PS C-raf antisense oligo in blocking C-raf mRNA expression in two cell lines. Similarly, each of the ME C-raf antisense oligos produced better heart allograft survival rates than did PS C-raf oligo. Furthermore, although the combination of PS C-raf antisense oligo with sirolimus (SRL) acted synergistically to extend heart allograft survival, the effect was potentiated by either of the ME-modified oligos.

CONCLUSIONS

C-raf inhibition extends heart allograft survival, and ME-modification potentiates antisense activity.

Perfusion of kidneys with unformulated "naked" intercellular adhesion molecule-1 antisense oligodeoxynucleotides prevents ischemic/reperfusion injury

BACKGROUND

We have previously shown that phosphorothioate intercellular adhesion molecule (ICAM)-1 antisense oligodeoxynucleotide (oligo) IP-9125 blocks the expression of rat ICAM-1 mRNA in rat L2 cells. A single ex situ perfusion of grafts with unformulated IP-9125, suspended in Euro-Collins solution, prolonged the survival of kidney allografts in rats. The present experiments examined whether perfusion of kidneys with unformulated IP-9125 prevents ischemic/reperfusion injury.

METHODS

Kidneys were perfused ex situ with 2 ml of Euro-Collins solution without or with IP-9125 and exposed to 30-min cold (4 degrees C storage time) and 30-min warm (anastomosis time) ischemia. Kidneys were then transplanted to syngeneic nephrectomized recipients.

RESULTS

Within 24 hr after transplantation, the glomerular filtration rate values were reduced by almost 60% to 0.49+/-0.14 ml/min from 1.20+/-0.27 ml/min in normal kidneys (P<0.001). Kidney perfusion with 10 mg of either IP-12140 (0.41+/-0.07 ml/min) or IP-13944 (0.47+/-0.07 ml/min) control oligo was ineffective. In contrast, perfusion with 10 mg of IP-9125 significantly improved kidney function (0.8+/-0.18 ml/min; P<0.005), whereas the lower doses of 2 mg (0.47+/-0.13 ml/min; NS) or 4 mg (0.54+/-0.04 ml/min; NS) had no significant effect. The glomerular filtration rate results were confirmed by measurements of blood creatinine (CR) levels at 24 hr after grafting: untreated recipients had a twofold higher CR value (0.70+/-0.14 mg/dl) compared with normal controls (0.65+/-0.07 mg/dl; P<0.001). Although perfusion with 10 mg of control IP-12140 (0.80+/-0.14 mg/dl) or IP-13944 (0.65+/-0.07 mg/dl) did not affect CR levels, perfusion with 10 mg of IP-9125 (0.45+/-0.07 mg/dl) lowered CR levels. The Western blots or reverse transcription-polymerase chain reaction experiments performed in kidney transplants within 24 hr after grafting showed that 10 mg of IP-9125 (but not control IP-12140) reduced the expression of ICAM-1 protein and ICAM-1 mRNA, respectively.

CONCLUSIONS

Perfusion of grafts with unformulated ICAM-1 antisense oligo specifically reduces intragraft ICAM-1 protein expression and prevents ischemic/reperfusion injury.

Prophylaxis of acute renal allograft rejection using FTY720 in combination with subtherapeutic doses of cyclosporine

BACKGROUND

In rodent transplant models, FTY720 exerts a synergistic affect with cyclosporine (CsA) to prolong allograft survival. The present experiments sought to test this combination in subhuman primates.

METHODS

Cynomolgus monkeys were transplanted with kidney allografts that were incompatible in mixed lymphocyte culture reactions. The animals were treated with daily intramuscular injections of CsA using doses selected to maintain whole blood trough concentrations at therapeutic values between 40 and 200 ng/ml. The 4 experimental groups included CsA without or with 0.1, 0.3, or 1 mg/kg/day FTY720 delivered daily by intravenous bolus injection. Therapeutic effects were suggested both by the graft histology of biopsy within the first 10 posttransplant days and by the length of host survival.

RESULTS

Whereas recipients treated with CsA alone rejected kidney allografts at a median survival time of 8.5 days (n=4), those treated with either 0.1 or 0.3 mg/kg/day FTY720 in addition to CsA showed significant prolongation of kidney allograft survival to 71 days (n=3; P<0.04) or 63 days (n=5; P<0.05), respectively. The hosts in the 1.0 mg/kg/day FTY720 group survived 48 days, with 2 of 5 recipients succumbing at 9 or 17 days postgraft, suggesting possible complications caused by overimmunosuppression. Biopsies of the 0.1 mg/kg/day FTY720 group on posttransplant day 7 documented mild to moderate rejection (grade I), indicated by multiple focal areas of tubular destruction. The histology results of transplants in the 0.3 or 1 mg/kg/day FTY720 group showed only minimal interstitial inflammatory infiltrates (borderline grade), with no evidence of tubular or arterial damage. Serum creatinine values among the animals in the 0.1 mg/kg/day FTY720 group showed increases in 2 of 3 recipients by day 20 and in the third by day 41 postgraft. Among the 0.3 mg/kg/day FTY720 group, 3 of 5 recipients maintained baseline creatinine values to 45 days postgraft; 1 recipient had stable kidney function for 120 days postgraft.

CONCLUSIONS

Addition of FTY720 therapy to a subtherapeutic CsA immunosuppressive regimen delays the rejection of renal allografts in subhuman primates.

Protection against allograft rejection with intercellular adhesion molecule-1 antisense oligodeoxynucleotides

BACKGROUND

We designed an antisense phosphorothioate oligodeoxynucleotide (oligo) to specifically inhibit the expression of rat intercellular adhesion molecule-1 (ICAM-1) mRNA (IP-9125).

METHODS

IP-9125 oligo was delivered intravenously by osmotic pump alone or in combination with cyclosporine (CsA) to recipients in order to prevent the rejection of kidney or heart allografts. In additional experiments, kidney allografts were perfused with IP-9125 before grafting.

RESULTS

IP-9125 inhibited ICAM-1 mRNA and ICAM-1 protein expression in rat aortic endothelial cells; scrambled controls IP-12140 and IP-13944 were ineffective. Untreated ACI (RT1a) recipients rejected Lewis (RT1l) kidney allografts at a mean survival time of 8.5+/-1.1 days. A 14-day intravenous administration of 2.5 mg/kg/day IP-9125 prolonged the survival of kidney allografts to 39.2+/-16.4 days; 5.0 mg/kg/day, to 43.0+/-17.5 days; and 10.0 mg/kg/day, to 50.4+/-21.6 days. In contrast, a scrambled control IP-12140 was not effective. A combination of 10 mg/kg/day IP-9125 and 1.0 mg/kg/day CsA delivered for 14 days synergistically extended kidney allograft survival times 88.5+/-7.5 days. In contrast, the combination of 10.0 mg/kg/day control IP-12140 with CsA was ineffective (20.7+/-3.2 days) when compared with CsA alone (20.2+/-4.0 days). Similar results were obtained for heart transplants in recipients treated with IP-9125 alone or in combination with CsA. Furthermore, in situ immunostaining showed that IP-9125 significantly reduced the expression of ICAM-1 protein in kidney allografts. Finally, perfusion of kidney grafts alone with 20.0 mg per 2 ml of IP-9125 protected kidney allografts from rejection (37.5+/-7.5 days; P < 0.001), whereas perfusion with 20 mg per 2 ml of control IP-12140 was ineffective (12.6+/-5.0 days).

CONCLUSIONS

Rat ICAM-1 IP-9125 oligo inhibits ICAM-1 protein expression in vitro and in vivo as well as blocks allograft rejection when used for pretreatment of donors, graft perfusion, or postoperative treatment of recipients.

Immunosuppressive effects of FTY720 alone or in combination with cyclosporine and/or sirolimus

BACKGROUND

We examined the ability of FTY720, a novel immunosuppressant that prolongs the survival of allografts in experimental animal models, to potentiate the immunosuppressive effects of cyclosporine (CsA) and/or sirolimus (SRL) in vitro and in vivo.

METHODS

FTY720 alone (10-5000 ng/ml) or in combination with other drugs was added to human peripheral blood lymphocytes (PBLs) undergoing stimulation in vitro with phytohemagglutinin (PHA) or OKT3 monoclonal antibody. The combination index (CI) values were calculated to evaluate the nature of the interactions between FTY720 and CsA and/or SRL: CI values <1 reflect synergistic, CI=1, additive, and CI>1, antagonistic interactions. In addition, Wistar Furth (RT1u) rat recipients of Buffalo (RT1b) heart allografts were treated with FTY720 alone or in combination with other agents. FTY720 alone was also tested to block small bowel or liver allograft rejection in rats.

RESULTS

FTY720 alone produced only modest inhibition of the proliferation of human PBL stimulated with PHA or OKT3 monoclonal antibody. In combination with CsA or SRL, however, FTY720 produced synergistic effects, namely, CI values of 0.58 and 0.36, respectively. A 14-day course of FTY720 (0.05-8.0 mg/kg/day) by oral gavage prolonged heart allograft survival in dose-dependent fashion. Although a 14-day oral course of CsA (1.0 mg/kg/day) alone was ineffective (mean survival time=7.0+/-0.7 vs. 6.4+/-0.6 days in treated vs. untreated hosts), treatment with a combination of 1.0 mg/kg/day CsA and 0.1 mg/kg/day FTY720 extended allograft survival to 62.4+/-15.6 days (P<0.001; CI=0.15). Similarly, a 14-day oral course of 0.08 mg(kg/day SRL alone was ineffective (6.8+/-0.6 days; NS), but the combination of SRL with 0.5 mg/kg/day FTY720 extended the mean survival time to 34.4+/-8.8 days (CI=0.28). The CsA/SRL (0.5/0.08 mg/kg/day) combination acted synergistically with FTY720 (0.1 mg/kg/day) to prolong heart survivals to >60 days (CI=0.18).

CONCLUSIONS

FTY720 potentiates the immunosuppressive effects of CsA and/or SRL both in vitro (by inhibiting of T-cell proliferative response) and in vivo (by inhibiting allograft rejection).

Relative tissue distributions of cyclosporine and sirolimus after concomitant peroral administration to the rat: evidence for pharmacokinetic interactions

The authors sought to determine the effect of concomitant peroral (PO) administration of cyclosporine (CsA) and sirolimus (SRL, rapamycin) on the tissue distributions of CsA and SRL in the rat. Groups of four adult male Wistar-Furth rats were treated for 14 days with 2.5, 5.0, or 10.0 mg CsA/kg x day. Other groups of four adult male Wistar-Furth rats were treated for 14 days with a 1-to-6.25 weight-to-weight ratio of SRL to CsA at SRL doses of 0.4, 0.8, or 1.6 mg/kg x day. Concentrations of CsA and SRL in homogenates of heart, intestinal, kidney, liver, lung, muscle, spleen, and testes were compared to those in whole blood (WB). There was a large, dose-dependent, distinctive distribution of CsA among rat tissues, as has previously been well documented. At a constant molar dose ratio, concomitant oral administration of SRL produced an approximately two-fold increase in the concentrations of CsA in rat tissues, although SRL did not change the CsA tissue-to-WB partition coefficients. Concomitant oral CsA administration produced dose-dependent increases in SRL tissue concentrations and decreases in the SRL tissue-to-WB partition coefficients. The increases in tissue and WB concentrations on coadministration of both agents may be explained either by an increase in absorption caused by competition between the two agents for binding sites on P-glycoprotein in the gut, a reduced rate of metabolism, or to an as yet unidentified elimination mechanism. The dose-independent and unchanged CsA tissue-to-WB partition coefficients suggest that SRL does not affect the equilibrium of CsA between the central and tissue compartments, namely the tissue uptake or intracellular binding. Altered values of the SRL tissue-to-WB partition coefficients suggest that, under the conditions studied, CsA disturbs the equilibrium of SRL between the central and tissue compartments.