Madigan, Theresa

AbstractBackgroundPlasma ammonia is commonly measured in the diagnostic evaluation of hospitalized newborns, but reference values are not well defined.MethodsWe prospectively enrolled newborns admitted to the level III/IV neonatal intensive care unit and level II intermediate special care nursery from January 2017 to January 2018. Infants with inborn errors of metabolism or liver disease were excluded. Plasma ammonia concentrations were measured once within the first week of life and evaluated by sex, gestational age, timing of the draw, blood collection method, and type of nutrition. Reference intervals were calculated.Results127 neonates were included; one third (34%) were term infants born at ≥37 weeks gestation, and two thirds (66%) were born preterm at <37 weeks gestation. Median plasma ammonia concentrations were 32 μmol/L (range <10 to 86 μmol/L). Median ammonia concentrations were higher among preterm compared to term infants (35 vs. 28 μmol/L, p = 0.0119), and term female compared to term male infants (34 vs. 26 μmol/L, p = 0.0228). There was no difference in median ammonia concentrations between female and male preterm infants, based on gestational age within the preterm group, timing of the blood draw, presence of hyperbilirubinemia, blood collection method, or type of nutritional intake.ConclusionsPlasma ammonia concentrations among newborns are higher than the expected adult concentrations and may vary by gestational age and sex. Blood collection method, type of nutrition, hyperbilirubinemia, and timing of the draw do not impact concentrations. We propose a reference limit of ≤82 μmol/L for newborns less than one week of age.

Abstract Background Respiratory syncytial virus (RSV) can cause severe lower respiratory tract infection (LRTI) in immunocompromised children. There is no standard effective treatment, though ribavirin (inhaled or oral), pooled human intravenous immunoglobulin (IVIG), and monoclonal anti-RSV antibody (palivizumab) have been described. RI-002 (ADMA Biologics Inc.) is a pooled human polyclonal IVIG that contains standardized levels of neutralizing anti-RSV antibodies. It was recently FDA-approved for prophylaxis in primary immunodeficiency patients and has been used as compassionate treatment for RSV LRTI in stem cell transplant patients. Methods Two children with T-cell lymphoblastic lymphoma, both undergoing delayed intensification chemotherapy, were diagnosed with RSV LRTI. They were both treated with RI-002 under an emergency FDA Investigational New Drug protocol. Results Patient 1, a 4-year-old boy, was admitted with fever, neutropenia and nasal congestion, and diagnosed with RSV infection on hospital day (HD) 5. On HD17, he was intubated for respiratory failure. IVIG, palivizumab, and daily oral ribavirin were administered. On HD18, he required high frequency oscillator ventilation, nitric oxide, and paralysis. He was given RI-002 (1.5 g/kg on HD20 and 0.75 g/kg on HD22). He was placed on veno-venous extracorporeal membrane oxygenation (ECMO) on HD23. RSV PCR crossing point (Cp) values trended higher, but remained positive (table). On HD33, RI-002 was re-dosed (0.75 g/kg). Pulmonary compliance and chest CTs improved (figure). On HD52, ECMO support was discontinued. He was discharged on HD88, and currently requires no respiratory support. Patient 2, a 5-year-old boy, was admitted with fever, neutropenia, nasal congestion, cough, and stridor and diagnosed with RSV infection (HD1). He required nasal cannula oxygen. IVIG and daily oral ribavirin were administered. He was given RI-002 (1.5 g/kg on HD3 and 0.75 g/kg on HD5). By HD5, he was afebrile; oxygen was discontinued. He was discharged HD6. Conclusion Human polyclonal IVIG containing standardized levels of neutralizing anti-RSV antibodies may be useful in the treatment of RSV LRTI in immunocompromised children. Future studies on the role of RI-002 in treatment of RSV infection in immunocompromised children are warranted. Disclosures All authors: No reported disclosures.

Abstract Background The BioFire FilmArray Gastrointestinal Panel (BioFire Diagnostics) (GIP) is a multiplex stool PCR test that detects 22 organisms. Studies in adults suggest that the diagnostic yield of the GIP in hospitalized patients is low. The utility of the GIP among hospitalized pediatric patients and indications for diagnostic stewardship of this test are not well described. Methods We conducted a retrospective chart review of hospitalized pediatric patients who had a GIP ordered between October 2015 and October 2017. Demographic, clinical, and laboratory information was extracted from the medical record. Statistical analysis was completed using JMP Pro 13.0.0 (SAS Institute Inc.). Results Over the 2-year study period, 193 GIPs were obtained on 155 individual pediatric patients. The mean patient age was 8 years and 59% were male. Forty-four percent of patients were immunocompromised and 21% had inflammatory bowel disease. The pediatric infectious disease (PID) team was consulted in 15% of patients at the time the test was ordered. The overall positivity rate of the GIP for one or more pathogens was 42% (Figure 1), with 76% of GIPs positive for one, 23% for two, and 1% for three pathogens. No parasitic infections were diagnosed. The GIP was more likely to be positive if GI symptom onset was prior to admission (48% vs. 24%, P = 0.004), if GI symptoms had been present for < 2 weeks vs. ≥2 weeks (52% vs. 20%, P = 0.0001), and if GI symptoms were the primary reason for the hospital admission (50% vs. 32%, P = 0.012). Only Clostridioides difficile or viral pathogens were detected in patients whose symptoms began in the hospital (Figure 2). Among patients with a positive test, 40% received treatment targeted at one or more of the detected pathogens (Figure 1). Enteropathogenic E.coli (EPEC) and Enteroaggregative E.coli (EAEC) were never treated (Figure 3). Conclusion The GIP was positive for one or more pathogens in 42% of hospitalized children for whom the test was ordered, and led to specific therapy in 40% of those with a positive test. EPEC and EAEC were not treated. The diagnostic yield of the GIP was higher if GI symptoms were present for <2 weeks, began before hospitalization, and were the primary reason for admission. The GIP was frequently obtained without guidance from the PID team. Disclosures R. Patel, CD Diagnostics, BioFire, Curetis, Merck, Hutchison Biofilm Medical Solutions, Accelerate Diagnostics, Allergan, and The Medicines Company: Grant Investigator, Research grant – monies paid to Mayo Clinic. Curetis, Specific Technologies, Selux Dx, GenMark Diagnostics, PathoQuest and Genentech: Consultant and Scientific Advisor, Consulting fee – monies paid to Mayo Clinic. ASM and IDSA: Travel reimbursement and editor’s stipends, Travel reimbursement and editor’s stipends. NBME, Up-to-Date and the Infectious Diseases Board Review Course: Varies, Honoraria. Mayo Clinic: Employee, Salary.

Abstract Background Medical trainees play a critical role in the prescribing of antimicrobials. Prescriber education is one of the CDC core elements of antimicrobial stewardship programs. Optimal strategies for educating residents about antimicrobials have not been identified; however, the common practice of teaching all classes of available antibiotics over a short period of time (usually a single 1–2 hour lecture or “bolus”) is generally not well received and likely ineffective. Methods We developed a novel antibiotic of the month (AOTM) education program (“continuous infusion”) for pediatric residents. It included a monthly 10-minute presentation by an infectious diseases physician or fellow about a single commonly prescribed antibiotic, a handout summarizing important aspects of the antibiotic and a display posted in the resident workroom. An anonymous survey was sent to all pediatric residents before and 6 months after implementation of the AOTM program. The survey consisted of questions on demographics, satisfaction with the program, and antibiotic knowledge. Responses were tabulated and analyzed using Microsoft Excel. Responses were summarized and reported as a proportion of total responses. Results Both pre- and post-implementation surveys were completed by 21 pediatric residents (51% response rate). Prior to the AOTM program, 55% of respondents felt very or somewhat uncomfortable about their current level of knowledge about antimicrobials and antimicrobial prescribing. Six months after initiation of the program, 86% and 76% agreed or strongly agreed that their knowledge of antimicrobials and antimicrobial resistance, respectively, had improved. After introduction of the program, 81% felt more comfortable or much more comfortable with antimicrobial prescribing. Fifty-seven percent had referenced the handout at some point after the teaching session and 100% agreed that the program was worthwhile continuing in the next academic year. Conclusion A continuous infusion of antimicrobial education in the form of an AOTM education program was well received among pediatric residents and increased their knowledge and comfort level with antimicrobial prescribing. Further studies to measure knowledge retention with this strategy are required. Disclosures All authors: No reported disclosures.

Background Kingella kingae is a known cause of osteoarticular infections in children younger than 4 years of age, but it is not always recoverable in culture. Molecular methods are increasingly used for diagnosis. Methods To facilitate diagnosis of K. kingae septic arthritis, we developed a real-time polymerase chain reaction (PCR) assay for the detection of K. kingae that targets the repeat-in-toxin gene (rtxB). Results We present three pediatric patients with K. kingae septic arthritis at our institution who were diagnosed using the real-time PCR assay. All underwent arthrotomy with irrigation and debridement and were symptom-free after 3 weeks of therapy with β-lactam antibiotics. Cultures of synovial fluid or tissue grew K. kingae in two of three; K. kingae real-time PCR was positive in all three patients. In addition, 11 cases of K. kingae osteoarticular infection were diagnosed through Mayo Medical Laboratories using this assay. The limit of detection of the real-time PCR assay was 73.7 colony-forming unit (CFU)/µL for tissue and 1.3 CFU/µL for synovial fluid. Conclusions PCR-based detection methods are faster and more sensitive than conventional culture-based methods for the diagnosis of K. kingae osteoarticular infections in children.