Central Nervous System Antimicrobial Exposure and Proposed Dosing for Anthrax Meningitis

BACKGROUND

The high mortality of systemic anthrax is likely a consequence of the severe central nervous system (CNS) inflammation that occurs in anthrax meningitis. Effective treatment of such infections requires, at a minimum, adequate cerebrospinal fluid (CSF) antimicrobial concentrations.

METHODS

We reviewed English medical literature and regulatory documents to extract information on serum and CSF exposures for antimicrobials with in vitro activity against Bacillus anthracis. Using CSF pharmacokinetic exposures and in vitro B. anthracis susceptibility data, we employed population pharmacokinetic modeling and Monte Carlo simulations to predict whether a specific antimicrobial dosage would likely achieve effective CSF antimicrobial activity in patients with normal to inflamed meninges (i.e., an intact to markedly disrupted blood brain barrier).

RESULTS

Probability of microbiologic success at achievable antimicrobial dosages was high (≥95%) for ciprofloxacin, levofloxacin (500 mg q12 h), meropenem, imipenem/cilastatin, penicillin G, ampicillin, ampicillin/sulbactam, doxycycline, and minocycline; acceptable (90-95%) for piperacillin/tazobactam and levofloxacin (750 mg q24 h); and low (<90%) for vancomycin, amikacin, clindamycin, and linezolid.

CONCLUSION

Prompt empiric antimicrobial therapy of patients with suspected or confirmed anthrax meningitis may reduce the high morbidity and mortality. Our data support using several β-lactam-, fluoroquinolone-, and tetracycline-class antimicrobials as first-line and alternative agents for treatment of patients with anthrax meningitis; all should achieve effective microbiologic exposures. Our data also suggest antimicrobials that should not be relied upon to treat suspected or documented anthrax meningitis. Furthermore, the protein synthesis inhibitors clindamycin and linezolid can decrease toxin production and may be useful components of combination therapy.

Clinical Practice Guideline by the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA): 2023 Guideline on Diagnosis and Management of Acute Bacterial Arthritis in Pediatrics

This clinical practice guideline for the diagnosis and treatment of acute bacterial arthritis (ABA) in children was developed by a multidisciplinary panel representing the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA). This guideline is intended for use by healthcare professionals who care for children with ABA, including specialists in pediatric infectious diseases and orthopedics. The panel's recommendations for the diagnosis and treatment of ABA are based upon evidence derived from topic-specific systematic literature reviews. Summarized below are the recommendations for the diagnosis and treatment of ABA in children. The panel followed a systematic process used in the development of other IDSA and PIDS clinical practice guidelines, which included a standardized methodology for rating the certainty of the evidence and strength of recommendation using the GRADE approach (Grading of Recommendations Assessment, Development and Evaluation) (see Figure 1). A detailed description of background, methods, evidence summary and rationale that support each recommendation, and knowledge gaps can be found online in the full text.

Contribution of Concurrent Comorbidities to Sepsis-Related Mortality in Preterm Infants ≤32 Weeks of Gestation at an Academic Neonatal Intensive Care Network

OBJECTIVE

 This study sought to identify concurrent major comorbidities in preterm infants ≤32 weeks of gestation that may have contributed to sepsis-related mortality following a diagnosis of bacteremia or blood culture-negative sepsis within the neonatal period (≤28 days of life).

STUDY DESIGN

 This is a retrospective chart review of infants ≤32 weeks of gestation who were admitted to a single academic network of multiple neonatal intensive care units between January 1, 2012, and December 31, 2015, to determine the primary cause(s) and timing of death in those diagnosed with bacteremia or blood culture-negative sepsis. Direct comparisons between early-onset sepsis (EOS; ≤72 hours) and late-onset sepsis (LOS; >72 hours) were made.

RESULTS

 In our study cohort, of 939 total patients with ≤32 weeks of gestation, 182 infants were diagnosed with 198 episodes of sepsis and 7.7% (14/182) died. Mortality rates did not significantly differ between neonates with bacteremia or blood culture-negative sepsis (7/14 each group), and those diagnosed with EOS compared with LOS (6/14 vs. 8/14). Nearly 80% (11/14) of infants were transitioned to comfort care prior to their death secondary to a coinciding diagnosis of severe grade-3 or -4 intraventricular hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, and/or intestinal perforation.

CONCLUSION

 Preexisting comorbidities commonly associated with extreme preterm birth contributed to sepsis-related mortality in our patient cohort.

KEY POINTS

· Concurrent comorbidities contribute to, and may artificially inflate, sepsis-related mortality.. · Absence of a consensus definition for neonatal sepsis complicates the investigation of infection.. · Accurate assessment of the incidence of sepsis in very low birth weight infants is vital for future investigations..

Pharmacokinetics, Safety, and Tolerability of Imipenem/Cilastatin/Relebactam in Children with Confirmed or Suspected Gram-Negative Bacterial Infections: A Phase 1b, Open-Label, Single-Dose Clinical Trial

Imipenem/cilastatin/relebactam is approved for the treatment of serious gram-negative bacterial infections in adults. This study assessed the pharmacokinetics (PK), safety, and tolerability of a single dose of imipenem/cilastatin/relebactam (with a fixed 2:1 ratio of imipenem/cilastatin to relebactam, and with a maximum dose of 15 mg/kg imipenem and 15 mg/kg cilastatin [≤500 mg imipenem and ≤500 mg cilastatin] and 7.5 mg/kg relebactam [≤250 mg relebactam]) in children with confirmed/suspected gram-negative bacterial infections receiving standard-of-care antibacterial therapy. In this phase 1, noncomparative study (ClinicalTrials.gov identifier, NCT03230916), PK parameters from 46 children were analyzed using both population modeling and noncompartmental analysis. The PK/pharmacodynamic (PD) target for imipenem was percent time of the dosing interval that unbound plasma concentration exceeded the minimum inhibitory concentration (%fT>MIC) of ≥30% (MIC = 2 mcg/mL). For relebactam, the PK/PD target was a free drug area under the plasma concentration-time curve (AUC) normalized to MIC (at 2 mcg/mL) of ≥8.0 (equivalent to an AUC from time zero extrapolated to infinity of ≥20.52 mcg·h/mL). Safety was assessed up to 14 days after drug infusion. For imipenem, the ranges for the geometric mean %fT>MIC and maximum concentration (Cmax ) across age cohorts were 56.5%-93.7% and 32.2-38.2 mcg/mL, respectively. For relebactam, the ranges of the geometric mean Cmax and AUC from 0 to 6 hours across age cohorts were 16.9-21.3 mcg/mL and 26.1-55.3 mcg·h/mL, respectively. In total, 8/46 (17%) children experienced ≥1 adverse events (AEs) and 2/46 (4%) children experienced nonserious AEs that were deemed drug related by the investigator. Imipenem and relebactam exceeded plasma PK/PD targets; single doses of imipenem/cilastatin/relebactam were well tolerated with no significant safety concerns identified. These results informed imipenem/cilastatin/relebactam dose selection for further pediatric clinical evaluation.

Pharmacokinetics and safety of a single dose of telavancin in pediatric subjects 2-17 years of age

Antimicrobial resistance increases infection morbidity in both adults and children, necessitating the development of new therapeutic options. Telavancin, an antibiotic approved in the United States for certain bacterial infections in adults, has not been examined in pediatric patients. The objectives of this study were to evaluate the short-term safety and pharmacokinetics (PK) of a single intravenous infusion of telavancin in pediatric patients. Single-dose safety and PK of 10 mg/kg telavancin was investigated in pediatric subjects >12 months to ≤17 years of age with known or suspected bacterial infection. Plasma was collected up to 24-h post-infusion and analyzed for concentrations of telavancin and its metabolite for noncompartmental PK analysis. Safety was monitored by physical exams, vital signs, laboratory values, and adverse events following telavancin administration. Twenty-two subjects were enrolled: 14 subjects in Cohort 1 (12-17 years), 7 subjects in Cohort 2 (6-11 years), and 1 subject in Cohort 3 (2-5 years). A single dose of telavancin was well-tolerated in all pediatric age cohorts without clinically significant effects. All age groups exhibited increased clearance of telavancin and reduced exposure to telavancin compared to adults, with mean peak plasma concentrations of 58.3 µg/mL (Cohort 1), 60.1 µg/mL (Cohort 2), and 53.1 µg/mL (Cohort 3). A 10 mg/kg dose of telavancin was well tolerated in pediatric subjects. Telavancin exposure was lower in pediatric subjects compared to adult subjects. Further studies are needed to determine the dose required in phase 3 clinical trials in pediatrics.

Subgroup analysis of phase 2 study of ceftolozane/tazobactam in neonates and young infants with pyelonephritis

Ceftolozane/tazobactam is approved for the treatment of patients from birth to <18 y old with complicated urinary tract infections (cUTI). This post hoc analysis evaluated the safety, efficacy, and pharmacokinetics (PK) of ceftolozane/tazobactam compared with meropenem in neonates and young infants. NCT03230838 was a phase 2, randomized, active comparator-controlled, double-blind study of patients from birth to <18 y of age with cUTI, including pyelonephritis, given ceftolozane/tazobactam or meropenem in a 3:1 ratio. This subset analysis included only neonates and young infants < 3 mo of age. The microbiologic modified intent-to-treat population (mMITT) included 20 patients (ceftolozane/tazobactam, n = 14; meropenem, n = 6). All patients had pyelonephritis at baseline; two patients in each treatment group had bacteremia (overall 4/20, 20%). Escherichia coli was the most common baseline pathogen (overall 16/20, 80%). Safety and efficacy results were similar between treatment groups and consistent with the overall pediatric population. There were no serious drug-related adverse events (AEs), no discontinuations due to AEs, and no AEs leading to death in either treatment group. For the ceftolozane/tazobactam and meropenem treatment groups, clinical cure rates in the mMITT population were 92.9% and 100%, respectively. The population PK analysis of neonates and young infants demonstrated similar ceftolozane and tazobactam exposures to those of adults, achieving pharmacodynamic targets associated with clinical and microbiologic cure. Ceftolozane/tazobactam has a favorable safety profile and achieves high clinical cure and microbiologic eradication rates in neonates and young infants < 3 mo of age with cUTI and pyelonephritis. IMPORTANCE Extrapolation of antibacterial agent pharmacokinetics from adults to newborns and young infants may not be appropriate; similarly, the clinical manifestations of infectious diseases and outcomes following antibacterial treatment may not be similar. Ceftolozane/tazobactam is an antibacterial drug combination active against Pseudomonas aeruginosa and other multidrug-resistant gram-negative bacteria. A clinical study led to the approval for ceftolozane/tazobactam in patients from birth to 18 y of age who have complicated urinary tract infections, including those with serious kidney infections. Based on data collected during that clinical study, we compared newborns and young infants who were treated with ceftolozane/tazobactam (14 patients) and those who were treated with meropenem (6 patients). We found that ceftolozane/tazobactam treatment of newborns and young infants up to 3 mo of age who have complicated urinary tract infections demonstrated a favorable safety profile and high clinical cure and microbiologic eradication rates, similar to meropenem.

Bacteriophage Therapy of Multidrug-resistant Achromobacter in an 11-Year-old Boy With Cystic Fibrosis Assessed by Metagenome Analysis

BACKGROUND

Cystic fibrosis (CF) is a genetic disease associated with lung disease characterized by chronic pulmonary infection, increasingly caused by multiple drug-resistant pathogens after repeated antibiotic exposure, limiting antibiotic treatment options. Bacteriophages can provide a pathogen-specific bactericidal treatment used with antibiotics to improve microbiologic and clinical outcomes in CF.

METHODS

Achromobacter species isolates from sputum of a chronically infected person with CF, were assessed for susceptibility to bacteriophages: 2 highly active, purified bacteriophages were administered intravenously every 8 hours, in conjunction with a 14-day piperacillin/tazobactam course for CF exacerbation. Sputum and blood were collected for metagenome analysis during treatment, with sputum analysis at 1-month follow-up. Assessments of clinical status, pulmonary status and laboratory evaluation for safety were conducted.

RESULTS

Bacteriophage administration was well-tolerated, with no associated clinical or laboratory adverse events. Metagenome analysis documented an 86% decrease in the relative proportion of Achromobacter DNA sequence reads in sputum and a 92% decrease in blood, compared with other bacterial DNA reads, comparing pretreatment and posttreatment samples. Bacteriophage DNA reads were detected in sputum after intravenous administration during treatment, and at 1-month follow-up. Reversal of antibiotic resistance to multiple antibiotics occurred in some isolates during treatment. Stabilization of lung function was documented at 1-month follow-up.

CONCLUSIONS

Bacteriophage/antibiotic treatment decreased the host pulmonary bacterial burden for Achromobacter assessed by metagenome analysis of sputum and blood, with ongoing bacteriophage replication documented in sputum at 1-month follow-up. Prospective controlled studies are needed to define the dose, route of administration and duration of bacteriophage therapy for both acute and chronic infection in CF.

Defining Variability in Evaluation and Management of Children with Chronic Osteomyelitis

Pediatric chronic osteomyelitis is a rare, debilitating condition lacking management guidelines. In a national survey of 162 pediatric infectious disease physicians through the Emerging Infections Network, tremendous variability in diagnostic approaches and management was noted, highlighting a need for a prospective study to better define the spectrum of pathogens and disease.

Safety and Efficacy of Ceftolozane/Tazobactam Versus Meropenem in Neonates and Children With Complicated Urinary Tract Infection, Including Pyelonephritis: A Phase 2, Randomized Clinical Trial

BACKGROUND

Ceftolozane/tazobactam, a cephalosporin-β-lactamase inhibitor combination, active against multidrug-resistant Gram-negative pathogens, is approved for treatment of adults with complicated urinary tract infections (cUTI). Safety and efficacy of ceftolozane/tazobactam in pediatric participants with cUTI, including pyelonephritis, were assessed.

METHODS

This phase 2 study (NCT03230838) compared ceftolozane/tazobactam with meropenem for treatment of cUTI in participants from birth to <18 years of age. The primary objective was safety and tolerability. Key secondary end points included clinical cure and per-participant microbiologic response rates at end of treatment (EOT) and test of cure (TOC) visits.

RESULTS

The microbiologic modified intent-to-treat (mMITT) population included 95 participants (ceftolozane/tazobactam, n = 71; meropenem, n = 24). The most common diagnosis and pathogen were pyelonephritis (ceftolozane/tazobactam, 84.5%; meropenem, 79.2%) and Escherichia coli (ceftolozane/tazobactam, 74.6%; meropenem, 87.5%); 5.7% (ceftolozane/tazobactam) and 4.8% (meropenem) of E. coli isolates were extended-spectrum β-lactamase-producers. Rates of adverse events were similar between treatment groups (any: ceftolozane/tazobactam, 59.0% vs. meropenem, 60.6%; drug-related: ceftolozane/tazobactam, 14.0% vs. meropenem, 15.2%; serious: ceftolozane/tazobactam, 3.0% vs. meropenem, 6.1%). Rates of clinical cure for ceftolozane/tazobactam and meropenem at EOT were 94.4% and 100% and at TOC were 88.7% and 95.8%, respectively. Rates of microbiologic eradication for ceftolozane/tazobactam and meropenem at EOT were 93.0% and 95.8%, and at TOC were 84.5% and 87.5%, respectively.

CONCLUSIONS

Ceftolozane/tazobactam had a favorable safety profile in pediatric participants with cUTI; rates of clinical cure and microbiologic eradication were high and similar to meropenem. Ceftolozane/tazobactam is a safe and effective new treatment option for children with cUTI, especially due to antibacterial-resistant Gram-negative pathogens.

Pediatric Community-acquired Pneumonia: What is it, and How Do We Study It?

Pediatric community-acquired pneumonia in pre-school aged children is a common diagnosis, frequently treated with antibiotics although most often caused by viruses. An accurate assessment of treatment-related clinical outcomes is dependent on identifying the pathogen(s) and their susceptibility to treatment interventions.

What Is the Appropriate Dose, Route, and Duration of Antibiotic Therapy for Pediatric Acute Hematogenous Osteomyelitis (AHO)? I Wish I Knew

Treatment of pediatric AHO requires antibiotic/surgical management. Considerable clinical experience exists, but with current knowledge of antibiotic pharmacokinetics and pharmacodynamics, recommendations for dosages for old or new antibiotics should be based on current standards for drug development whenever possible.

1314. Defining Variability in the Evaluation and Management of Children with Chronic Osteomyelitis

Background

Pediatric chronic osteomyelitis (COM) is an uncommon, poorly defined, debilitating disorder often requiring multiple surgeries and prolonged antibiotic courses. Serious long-term sequelae may occur. As accepted diagnostic criteria do not exist, assessments of disease incidence, medical/surgical approach to management and outcomes are lacking.

Methods

We created a 14-question web-based survey sent to 390 pediatric infectious disease (PID) physician members of the Emerging Infections Network of the Infectious Diseases Society of America. With no standard definition of COM, respondents were asked to conceptualize this disease as they would during routine clinical practice. Of the 148 (38%) survey respondents so far (Table 1), 126 (85%) reported caring for children with COM. We assessed provider characteristics, diagnostic approach, and site-standard surgical and antibiotic management (including oral and intravenous [IV] antimicrobial choice and duration). We performed descriptive statistics on survey results.

Results

Of the 126 respondents, most were >5 years post-fellowship training and nearly half reported managing 3-6 cases of COM per year (Table 2). Prolonged duration of symptoms (79%), normal inflammatory markers (45%), and abnormal plain films (44%) were the most common findings used for diagnosis; however, diagnostic criteria varied. The most common risk factor was orthopedic implants (44%). Management choices and duration are in Figure 1. Most treated with IV antibiotics for < 2 weeks (34%), continuing oral antibiotics for at least 3-6 months (55%). In COM with retained orthopedic implant, most physicians (48%) use oral therapy until implant removal. Considerations for transition from IV to oral antibiotics included improved physical examination (60%), inflammatory markers (52%), extent of disease (55%), causative organism (41%) and location of infection (38%). Though 85% reported being comfortable diagnosing and managing COM, practices varied widely.

Reported approaches to surgical management (a), duration of IV antibiotics (b), and duration of oral antibiotics (c) in children with COM, and management of COM in patients with implanted hardware (d)

Responses from 126 pediatric infectious diseases physician participating in an Emerging Infections Network survey regarding diagnosis and management of chronic osteomyelitis (COM). Figure 1a) missing data for 2 respondents; figure 1b) missing data for 5 respondents; figure 1c) missing data for 2 respondents; figure 1d) missing data for 9 respondents. COM: Chronic osteomyelitis; IV: intravenous; abx: antibiotics.

Conclusion

Pediatric COM is a complex infection. Formal diagnostic criteria and future prospective studies for medical/surgical management by pathogen/site of infection and presence of foreign material are needed to optimize care and outcomes.

Disclosures

Daniel Benjamin, Jr., MD PhD MPH, Allergan: Advisor/Consultant|Melinta Therapuetics: Advisor/Consultant|Syneos Health: Advisor/Consultant.

Clinical Features of Patients Hospitalized for All Routes of Anthrax, 1880-2018: A Systematic Review

BACKGROUND

Anthrax is a toxin-mediated zoonotic disease caused by Bacillus anthracis, with a worldwide distribution recognized for millennia. Bacillus anthracis is considered a potential biowarfare agent.

METHODS

We completed a systematic review for clinical and demographic characteristics of adults and children hospitalized with anthrax (cutaneous, inhalation, ingestion, injection [from contaminated heroin], primary meningitis) abstracted from published case reports, case series, and line lists in English from 1880 through 2018, assessing treatment impact by type and severity of disease. We analyzed geographic distribution, route of infection, exposure to anthrax, and incubation period.

RESULTS

Data on 764 adults and 167 children were reviewed. Most cases reported for 1880 through 1915 were from Europe; those for 1916 through 1950 were from North America; and from 1951 on, cases were from Asia. Cutaneous was the most common form of anthrax for all populations. Since 1960, adult anthrax mortality has ranged from 31% for cutaneous to 90% for primary meningitis. Median incubation periods ranged from 1 day (interquartile range [IQR], 0-4) for injection to 7 days (IQR, 4-9) for inhalation anthrax. Most patients with inhalation anthrax developed pleural effusions and more than half with ingestion anthrax developed ascites. Treatment and critical care advances have improved survival for those with systemic symptoms, from approximately 30% in those untreated to approximately 70% in those receiving antimicrobials or antiserum/antitoxin.

CONCLUSIONS

This review provides an improved evidence base for both clinical care of individual anthrax patients and public health planning for wide-area aerosol releases of B. anthracis spores.

Systematic Review of Hospital Treatment Outcomes for Naturally Acquired and Bioterrorism-Related Anthrax, 1880-2018

BACKGROUND

Bacillus anthracis can cause anthrax and is a potential bioterrorism agent. The 2014 Centers for Disease Control and Prevention recommendations for medical countermeasures against anthrax were based on in vitro data and expert opinion. However, a century of previously uncompiled observational human data that often includes treatment and outcomes is available in the literature for analysis.

METHODS

We reviewed treatment outcomes for patients hospitalized with anthrax. We stratified patients by meningitis status, route of infection, and systemic criteria, then analyzed survival by treatment type, including antimicrobials, antitoxin/antiserum, and steroids. Using logistic regression, we calculated odds ratios and 95% confidence intervals to compare survival between treatments. We also calculated hospital length of stay. Finally, we evaluated antimicrobial postexposure prophylaxis (PEPAbx) using data from a 1970 Russian-language article.

RESULTS

We identified 965 anthrax patients reported from 1880 through 2018. After exclusions, 605 remained: 430 adults, 145 children, and 30 missing age. Survival was low for untreated patients and meningitis patients, regardless of treatment. Most patients with localized cutaneous or nonmeningitis systemic anthrax survived with 1 or more antimicrobials; patients with inhalation anthrax without meningitis fared better with at least 2. Bactericidal antimicrobials were effective for systemic anthrax; addition of a protein synthesis inhibitor(s) (PSI) to a bactericidal antimicrobial(s) did not improve survival. Likewise, addition of antitoxin/antiserum to antimicrobials did not improve survival. Mannitol improved survival for meningitis patients, but steroids did not. PEPAbx reduced risk of anthrax following exposure to B. anthracis.

CONCLUSIONS

Combination therapy appeared to be superior to monotherapy for inhalation anthrax without meningitis. For anthrax meningitis, neither monotherapy nor combination therapy were particularly effective; however, numbers were small. For localized cutaneous anthrax, monotherapy was sufficient. For B. anthracis exposures, PEPAbx was effective.

Anthrax Meningoencephalitis and Intracranial Hemorrhage

The neurological sequelae of Bacillus anthracis infection include a rapidly progressive fulminant meningoencephalitis frequently associated with intracranial hemorrhage, including subarachnoid and intracerebral hemorrhage. Higher mortality than other forms of bacterial meningitis suggests that antimicrobials and cardiopulmonary support alone may be insufficient and that strategies targeting the hemorrhage might improve outcomes. In this review, we describe the toxic role of intracranial hemorrhage in anthrax meningoencephalitis. We first examine the high incidence of intracranial hemorrhage in patients with anthrax meningoencephalitis. We then review common diseases that present with intracranial hemorrhage, including aneurysmal subarachnoid hemorrhage and spontaneous intracerebral hemorrhage, postulating applicability of established and potential neurointensive treatments to the multimodal management of hemorrhagic anthrax meningoencephalitis. Finally, we examine the therapeutic potential of minocycline, an antimicrobial that is effective against B. anthracis and that has been shown in preclinical studies to have neuroprotective properties, which thus might be repurposed for this historically fatal disease.

Solithromycin in Children and Adolescents With Community-acquired Bacterial Pneumonia

BACKGROUND

Solithromycin is a new macrolide-ketolide antibiotic with potential effectiveness in pediatric community-acquired bacterial pneumonia (CABP). Our objective was to evaluate its safety and effectiveness in children with CABP.

METHODS

This phase 2/3, randomized, open-label, active-control, multicenter study randomly assigned solithromycin (capsules, suspension or intravenous) or an appropriate comparator antibiotic in a 3:1 ratio (planned n = 400) to children 2 months to 17 years of age with CABP. Primary safety endpoints included treatment-emergent adverse events (AEs) and AE-related drug discontinuations. Secondary effectiveness endpoints included clinical improvement following treatment without additional antimicrobial therapy.

RESULTS

Unrelated to safety, the sponsor stopped the trial prior to completion. Before discontinuation, 97 participants were randomly assigned to solithromycin (n = 73) or comparator (n = 24). There were 24 participants (34%, 95% CI, 23%-47%) with a treatment-emergent AE in the solithromycin group and 7 (29%, 95% CI, 13%-51%) in the comparator group. Infusion site pain and elevated liver enzymes were the most common related AEs with solithromycin. Study drug was discontinued due to AEs in 3 subjects (4.3%) in the solithromycin group and 1 (4.2%) in the comparator group. Forty participants (65%, 95% CI, 51%-76%) in the solithromycin group achieved clinical improvement on the last day of treatment versus 17 (81%, 95% CI, 58%-95%) in the comparator group. The proportion achieving clinical cure was 60% (95% CI, 47%-72%) and 68% (95% CI, 43%-87%) for the solithromycin and comparator groups, respectively.

CONCLUSIONS

Intravenous and oral solithromycin were generally well-tolerated and associated with clinical improvement in the majority of participants treated for CABP.

Decrease in Pediatric Invasive Pneumococcal Disease During the COVID-19 Pandemic

Measures to limit SARS-CoV-2 transmission in 2020 reduced other viral infections. Among 7 US children's hospitals, invasive pneumococcal disease cumulative incidence decreased by 46% in 2020 vs 2017-2019. Limited droplet transmission of pneumococci and preceding viral pathogens may be responsible.

Implementation of Vancomycin Therapeutic Monitoring Guidelines: Focus on Bayesian Estimation Tools in Neonatal and Pediatric Patients

BACKGROUND

The 2020 consensus guidelines for vancomycin therapeutic monitoring recommend using Bayesian estimation targeting the ratio of the area under the curve over 24 hours to minimum inhibitory concentration as an optimal approach to individualize therapy in pediatric patients. To support institutional guideline implementation in children, the objective of this study was to comprehensively assess and compare published population-based pharmacokinetic (PK) vancomycin models and available Bayesian estimation tools, specific to neonatal and pediatric patients.

METHODS

PubMed and Embase databases were searched from January 1994 to December 2020 for studies in which a vancomycin population PK model was developed to determine clearance and volume of distribution in neonatal and pediatric populations. Available Bayesian software programs were identified and assessed from published articles, software program websites, and direct communication with the software company. In the present review, 14 neonatal and 20 pediatric models were included. Six programs (Adult and Pediatric Kinetics, BestDose, DoseMeRx, InsightRx, MwPharm++, and PrecisePK) were evaluated.

RESULTS

Among neonatal models, Frymoyer et al and Capparelli et al used the largest PK samples to generate their models, which were externally validated. Among the pediatric models, Le et al used the largest sample size, with multiple external validations. Of the Bayesian programs, DoseMeRx, InsightRx, and PrecisePK used clinically validated neonatal and pediatric models.

CONCLUSIONS

To optimize vancomycin use in neonatal and pediatric patients, clinicians should focus on selecting a model that best fits their patient population and use Bayesian estimation tools for therapeutic area under the -curve-targeted dosing and monitoring.

Impact of Cell-Free Next-Generation Sequencing on Management of Pediatric Complicated Pneumonia

BACKGROUND

Community-acquired pneumonia (CAP) is common in pediatrics. More severe complicated CAP (cCAP) requires broad-spectrum empirical therapy. Cell-free plasma next-generation sequencing (cfNGS), a DNA-based diagnostic tool, could be used to guide therapy. We retrospectively compared the pathogen identification rate of cfNGS to that of standard culture methods and assessed the impact of cfNGS on antibiotic therapy in children hospitalized for cCAP.

METHODS

We conducted a retrospective review of children aged 3 months to 18 years hospitalized for cCAP with cfNGS results from January 24, 2018, to December 31, 2020. We compared the positivity rate of conventional microbiologic diagnostic testing with that of cfNGS and the impact on clinical management, including changes in antibiotic therapy.

RESULTS

We identified 46 hospitalized children with cCAP with cfNGS results. Of these children, 34 also had blood cultures (1 positive for pathogen; 3%) and 37 had pleural fluid cultures (10 positive for pathogen; 27%). Of the 46 children, positive cfNGS testing results were positive for pathogen in 45 (98%), with the causative pathogen identified in 41 (89%). cfNGS was the only method for pathogen identification in 32 children (70%). cfNGS results changed management in 36 (78%) of 46 children, with the antibiotic spectrum narrowed in 29 (81%).

CONCLUSIONS

cfNGS provided a higher diagnostic yield in our pediatric cCAP cohort compared with conventional diagnostic testing and affected management in 78% of children. Prospective studies are needed to better characterize the clinical outcome, cost-effectiveness, and antimicrobial stewardship benefits of cfNGS in pediatric cCAP.

Spectrum of Viral Pathogens Identified in Children with Clinical Myocarditis (Pre-Coronavirus Disease-2019, 2000-2018): Etiologic Agent Versus Innocent Bystander

OBJECTIVE

To identify the etiologies of viral myocarditis in children in the pre-coronavirus disease 2019 era.

STUDY DESIGN

This was a retrospective review of all patients (age <18 years) diagnosed with myocarditis and hospitalized at Rady Children's Hospital San Diego between 2000 and 2018.

RESULTS

Twenty-nine patients met inclusion criteria. Of 28 (97%) patients who underwent testing for viruses, polymerase chain reaction was used in 24 of 28 (86% of cases), and 16 of 24 (67%) detected a virus. Pathogens were rhinovirus (6), influenza A/B (4), respiratory syncytial virus (RSV) (3), coronavirus (3), parvovirus B19 (2), adenovirus (2), and coxsackie B5 virus, enterovirus, and parainfluenza virus type 2 in one case each. Six (21%) patients had no pathogen detected but imaging and other laboratory test results were compatible with myocarditis. Age 0-2 years was associated with RSV, influenza A/B, coronavirus, and enteroviruses (P < .001). Twenty-one patients (72%) experienced full clinical recovery. Three patients (10%) required venoarterial extracorporeal membrane oxygenation (VA-ECMO), and all 3 recovered. Three others (10%) required and underwent successful cardiac transplantation without complications. Two patients (7%) died 9-10 days after hospitalization (1 had RSV and 1 had influenza A/B). Two other patients presented with complete atrioventricular block; 1 case (rhinovirus) resolved spontaneously, and 1 (coronavirus) resolved after support with VA-ECMO. Age <2 years, female sex, lower ejection fraction at admission, and greater initial and peak levels of brain natriuretic peptide were significant predictors of critical outcomes (use of VA-ECMO, listing for cardiac transplantation, and death).

CONCLUSIONS

Viral nucleic acid-based testing revealed a wider spectrum of viruses that could be associated with myocarditis in children than previously reported and traditionally anticipated. A predilection of certain pathogens in the very young patients was observed. Whether the observed range of viral agents reflects an undercurrent of change in viral etiology or viral detection methods is unclear, but the wider spectrum of viral pathogens found underscores the usefulness of polymerase chain reaction testing to explore possible viral etiologies of myocarditis in children.

Population Pharmacokinetic Modeling and Probability of Pharmacodynamic Target Attainment for Ceftazidime-Avibactam in Pediatric Patients Aged 3 Months and Older

Increasing prevalence of infections caused by antimicrobial-resistant gram-negative bacteria represents a global health crisis, and while several novel therapies that target various aspects of antimicrobial resistance have been introduced in recent years, few are currently approved for children. Ceftazidime-avibactam is a novel β-lactam β-lactamase inhibitor combination approved for adults and children 3 months and older with complicated intra-abdominal infection, and complicated urinary tract infection or hospital-acquired ventilator-associated pneumonia (adults only in the United States) caused by susceptible gram-negative bacteria. Extensive population pharmacokinetic (PK) data sets for ceftazidime and avibactam obtained during the adult clinical development program were used to iteratively select, modify, and validate the approved adult dosage regimen (2,000-500 mg by 2-hour intravenous (IV) infusion every 8 hours (q8h), with adjustments for renal function). Following the completion of one phase I (NCT01893346) and two phase II ceftazidime-avibactam studies (NCT02475733 and NCT02497781) in children, adult PK data sets were updated with pediatric PK data. This paper describes the development of updated combined adult and pediatric population PK models and their application in characterizing the population PK of ceftazidime and avibactam in children, and in dose selection for further pediatric evaluation. The updated models supported the approval of ceftazidime-avibactam pediatric dosage regimens (all by 2-hour IV infusion) of 50-12.5 mg/kg (maximum 2,000-500 mg) q8h for those ≥6 months to 18 years old, and 40-10 mg/kg q8h for those ≥3 to 6 months old with creatinine clearance > 50 mL/min/1.73 m2 .

183. Decrease in Invasive Pneumococcal Disease in 7 United States Children’s Hospitals during the COVID-19 Pandemic

Background

During the 2020 SARS-CoV-2 pandemic, physical distancing and mask use guidelines were implemented resulting in a decline in the number of infections caused by influenza, respiratory syncytial virus and otitis media. A surveillance analysis from England and Taiwan showed a decline in invasive pneumococcal disease (IPD) (Clin Infect Dis. 2021;72: e65-75 and J Infect. 2021;82:296-297). We hypothesized that COVID mitigation efforts resulted in a decrease in incidence of pediatric IPD within the U.S. during 2020 compared to previous years.

Methods

We reviewed all cases of IPD among 7 children’s hospitals from the U.S. Pediatric Multicenter Pneumococcal Surveillance Group from 2017-2020. IPD was defined by the isolation of Streptococcus pneumoniae from normally sterile sites (eg. blood, cerebrospinal, pleural, synovial or peritoneal fluid). Pneumococcal pneumonia was defined as an abnormal chest radiograph in the presence of a positive blood, pleural fluid or lung culture. Mastoiditis was identified by positive middle ear, subperiosteal abscess or mastoid bone culture. Serotypes were determined by the capsular swelling method. Hospital admission numbers were obtained for incidence calculations. Statistical analyses were performed using STATA11. A p< 0.05 was considered significant.

Results

A total of 410 IPD cases were identified. The cumulative incidence of IPD (0-22 years of age) decreased from 99.2/100,000 admissions in 2017-2019 to 53.8/100,000 admissions in 2020 (risk ratio 0.54, CI: 0.40-0.72, p< 0.00001). Pneumococcal bacteremia and pneumonia decreased significantly in 2020 (p< 0.05), and although not statistically significant, there were fewer cases of meningitis and mastoiditis when compared to previous years (p=0.08) (Figure 1). Sex, race, age or presence of comorbidities were not significantly different between groups. Most common serotypes in 2020 were 35B, 3 and 15B/C (Figure 2).

Conclusion

The observed decline in IPD cases during the first year of the SARS-CoV-2 pandemic is likely associated with mask use and physical distancing limiting transmission of S. pneumoniae via droplets and viral infections frequently preceding IPD. These precautions might be useful in the future to decrease IPD, especially in high-risk patients.

Disclosures

Sheldon L. Kaplan, MD, Pfizer (Research Grant or Support) Tina Q. Tan, MD, GSK (Individual(s) Involved: Self): Advisor or Review Panel member, Grant/Research Support; ILiAD (Individual(s) Involved: Self): Advisor or Review Panel member; Merck (Individual(s) Involved: Self): Advisor or Review Panel member, Grant/Research Support; Moderna (Individual(s) Involved: Self): Advisor or Review Panel member; Pfizer (Individual(s) Involved: Self): Advisor or Review Panel member Pia S. Pannaraj, MD, MPH, Pfizer (Grant/Research Support)Sanofi-Pasteur (Advisor or Review Panel member)Seqirus (Advisor or Review Panel member) Larry Givner, MD, AstraZeneca (Advisor or Review Panel member) Kristina G. Hulten, PhD, Pfizer (Research Grant or Support)

1150. Pediatric Osteoarticular Infections Caused by Mycobacteria Tuberculosis Complex: A Twenty-Six Year Review of Cases in San Diego, California

Background

Osteoarticular infections (OAI) account for 10-20% of extrapulmonary Mycobacteria tuberculosis (MTB) complex infections in children. Given the rarity of MTB OAI, the epidemiology, disease manifestations, and treatment are poorly characterized. We describe 21 children treated for MTB complex OAI over a 26-year period at a tertiary pediatric center in southern California.

Methods

We conducted a retrospective review of children diagnosed with MTB complex OAI and cared for between 31 Dec 1992 to 31 Dec 2018 at a single tertiary care pediatric hospital with close proximity to the United States-Mexico border.

Results

We identified 21 children with MTB complex OAI during the study period (Table 1). Concurrent pulmonary disease (4.8%), meningitis (9.5%), and intra-abdominal involvement (14.3%) were all observed. MTB complex was identified by culture from operative samples in 15/21 children (71.4%); 8/15 (51.3%) cultures were positive for Mycobacterium bovis. Of the eight cases of vertebral OAI (the most common site), one was culture-positive for M. bovis. Open bone biopsy was the most common procedure for procurement of a tissue sample and had the highest culture yield (Table 2). The median duration of antimicrobial therapy was 52 weeks (IQR 52-58). Successful completion of therapy was documented in 15 children (71.4%). Seven children (33.3%) experienced long term sequelae related to their infection.

Table 1. Twenty-one children with Mycobacteria tuberculosis complex osteoarticular infections.

Table 2. Surgical sample type and percent positivity.

Conclusion

Among the 21 children with MTB complex OAI assessed, 8 of 15 (53.3%) children with a positive tissue culture had M. bovis (intrinsically resistant to pyrazinamide), representing a higher percentage than in previous reports and potentially reflecting its presence in unpasteurized dairy products in the California-Baja region. Local epidemiological trends in endemic MTB complex species should be considered when evaluating and managing MTB complex OAI. Bone biopsy produced the highest culture yield in this study. Given the rarity of this disease, multicenter collaborative studies are needed to improve our understanding of the presentation and management of pediatric MTB complex OAI.

Disclosures

Vanessa Raabe, MD, MSc, Pfizer (Scientific Research Study Investigator, Other Financial or Material Support, Editorial support)Sanofi (Scientific Research Study Investigator)

1159. Pharmacokinetics, Safety, and Tolerability of Imipenem/Cilastatin/Relebactam in Pediatric Participants With Confirmed or Suspected Gram-negative Bacterial Infections: A Phase 1b, Open-label, Single-Dose Clinical Trial

Background

Imipenem/cilastatin/relebactam (IMI/REL) is approved for treating hospital-acquired/ventilator-associated bacterial pneumonia, complicated urinary tract infection, and complicated intra-abdominal infection in adults. This study assessed single-dose pharmacokinetics (PK), safety, and tolerability of IMI/REL in neonatal and pediatric participants with confirmed or suspected gram-negative bacterial infections.

Methods

This was a phase 1, open-label, non-comparative study (NCT03230916). Age- and weight-adjusted dosing is summarized in Table 1. The primary objective was to characterize the PK profiles for imipenem and relebactam after a single intravenous dose of IMI/REL. PK parameters were analyzed using population modeling. The PK target for imipenem was the percent time of the dosing interval that the unbound plasma concentration exceeded the minimum inhibitory concentration (%fT >MIC) of ≥30% (MIC used, 2 µg/mL). The PK target for relebactam was an area under the curve (AUC)/MIC ratio >8 (MIC used, 2 µg/mL), corresponding to AUC0-24h >58.88 μM∙h. Safety and tolerability were assessed for up to 14 days after drug infusion.

Results

Of the 46 participants who received IMI/REL, 42 were included in the PK analysis. The mean plasma concentration-time profiles for imipenem and relebactam were generally comparable across age cohorts (Figure). For imipenem, the geometric mean %ƒT >MIC ranged from 50% to 94% and the mean maximum concentration (C_max) ranged from 65 μM to 126 μM (Table 2). For relebactam, the geometric C_max ranged from 33 μM to 87 μM and mean AUC_0-6h ranged from 51 μM·h to 159 μM·h across the age cohorts (Table 2). IMI/REL was well tolerated with 8 (17.4%) participants experiencing ≥1 adverse events (AE) and 2 (4.3%) participants experiencing AE that were deemed drug related by the investigator. Drug-related AE were increased alanine aminotransferase, increased aspartate aminotransferase, anemia, and diarrhea, which were non-serious, mild in severity, and resolved within the follow-up period of 14 days.

Figure 1

Conclusion

Imipenem and relebactam exceeded the pediatric plasma PK targets across pediatric age cohorts in the study; the single doses of IMI/REL were well tolerated. These results will inform IMI/REL dose selection for further pediatric clinical evaluation.

Disclosures

Camilla Tøndel, MD, PhD, Merck & Co., Inc., (Grant/Research Support) Emmanuel Roilides, MD, PhD, FIDSA, FAAM, FESCMID, FECMM, FISAC, Merck Sharp & Dohme Corp. (Consultant, Grant/Research Support) Matthew S. Kelly, MD, MPH, Merck Sharp & Dohme Corp. (Consultant, Grant/Research Support) Munjal Patel, PhD, Merck Sharp & Dohme Corp. (Employee, Shareholder) Pavan Vaddady, PhD, Merck Sharp & Dohme Corp. (Employee) Alok Maniar, MD, MPH, Merck Sharp & Dohme Corp. (Employee, Shareholder) Ying Zhang, PhD, Merck & Co., Inc. (Employee, Shareholder) Amanda Paschke, MD MSCE, Merck Sharp & Dohme Corp. (Employee, Shareholder) Joan R. Butterton, MD, Merck Sharp & Dohme Corp. (Employee, Shareholder) Luke F. Chen, MBBS MPH MBA FRACP FSHEA FIDSA, Merck (Employee)

1143. Safety and Efficacy of Ceftolozane/Tazobactam Versus Meropenem in Neonatal and Pediatric Participants With Complicated Urinary Tract Infection, Including Pyelonephritis: A Phase 2, Randomized, Clinical Trial

Background

Ceftolozane/tazobactam (C/T) is a cephalosporin–β-lactamase inhibitor combination approved to treat complicated urinary tract infections (cUTI), complicated intra-abdominal infections, and nosocomial pneumonia in adults. Safety and efficacy of C/T in neonatal and pediatric participants with cUTI was assessed.

Methods

This phase 2, randomized, double-blind study (NCT03230838) compared C/T with meropenem (MEM) for treatment of cUTI, including pyelonephritis in participants from birth to 18 years of age. Treatment duration was 7-14 days. After 3 days of intravenous therapy, optional oral step-down therapy was allowed. Participants were stratified and dosed by age group (Table 1). The primary objective was to evaluate the safety and tolerability of C/T compared with MEM, and key secondary end points included clinical response and per-participant microbiologic response at end of treatment (EOT) and test of cure (TOC).

Results

Participants were randomized 3:1 and treated with C/T (n=100) or MEM (n=33). The microbiologic modified intent-to-treat population (mMITT) included 95 participants in the C/T (n=71) and MEM (n=24) arms; the most common reason for mMITT exclusion was lack of a qualifying baseline uropathogen (28.4%). Pyelonephritis was the most common baseline diagnosis (83.2%), and Escherichia coli was the most common qualifying baseline uropathogen (77.9%). Overall mean treatment duration was comparable in both arms (C/T, 10.2 days; MEM, 10.7); a total of 50 (70.4%) and 20 (83.3%) participants switched to optional oral step-down therapy in the C/T and MEM arms, respectively, both for a mean of approximately 6 days. The overall incidence of adverse events (AE; all and drug related), serious AE (SAE), and AE leading to discontinuation was comparable between C/T and MEM arms. There were no AE leading to death, drug-related SAE, or discontinuations due to drug-related AE or SAE (Table 2). For C/T and MEM, rates of clinical cure and microbiologic eradication at EOT and TOC were high (Figure).

Conclusion

In this study, C/T was well tolerated with a safety profile comparable to MEM and to the previously reported safety profile for C/T in adults with cUTI. C/T achieved high clinical cure and microbiologic eradication rates and is a potential new treatment option for children with cUTI.

Disclosures

Emmanuel Roilides, MD, PhD, FIDSA, FAAM, FESCMID, Merck Sharp & Dohme Corp. (Consultant, Grant/Research Support) Negar Ashouri, MD, Merck Sharp & Dohme Corp. (Grant/Research Support) Matthew G. Johnson, MD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Julia Lonchar, MSc, Merck Sharp & Dohme Corp. (Employee, Shareholder) Feng-Hsiu Su, MPH, MBA, Merck Sharp & Dohme Corp. (Employee, Shareholder) Jennifer A. Huntington, PharmD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Myra W. Popejoy, PharmD, Merck Sharp & Dohme Corp. (Employee) Mekki Bensaci, PhD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee) Carisa S. De Anda, PharmD, Merck Sharp & Dohme Corp. (Employee, Shareholder) Elizabeth G. Rhee, MD, Merck Sharp & Dohme Corp (Employee, Shareholder) Christopher Bruno, MD, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA (Employee)

Clinical Practice Guideline by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America: 2021 Guideline on Diagnosis and Management of Acute Hematogenous Osteomyelitis in Pediatrics

This clinical practice guideline for the diagnosis and treatment of acute hematogenous osteomyelitis (AHO) in children was developed by a multidisciplinary panel representing Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA). This guideline is intended for use by healthcare professionals who care for children with AHO, including specialists in pediatric infectious diseases, orthopedics, emergency care physicians, hospitalists, and any clinicians and healthcare providers caring for these patients. The panel's recommendations for the diagnosis and treatment of AHO are based upon evidence derived from topic-specific systematic literature reviews. Summarized below are the recommendations for the diagnosis and treatment of AHO in children. The panel followed a systematic process used in the development of other IDSA and PIDS clinical practice guidelines, which included a standardized methodology for rating the certainty of the evidence and strength of recommendation using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. A detailed description of background, methods, evidence summary and rationale that support each recommendation, and knowledge gaps can be found online in the full text.

Ceftolozane/Tazobactam in Neonates and Young Infants: The Challenges of Collecting Pharmacokinetics and Safety Data in This Vulnerable Patient Population

OBJECTIVE

New treatments are needed for multidrug-resistant (MDR) gram-negative infections in neonates. Ceftolozane/tazobactam is a β-lactam/β-lactamase inhibitor combination that has broad-spectrum activity against most common gram-negative bacteria, including MDR strains. We evaluated pharmacokinetics (PK) and safety of ceftolozane/tazobactam in term and premature neonates and young infants.

STUDY DESIGN

This is a subgroup analysis of a phase 1, noncomparative, open-label, multicenter study that characterized the PK, safety, and tolerability of a single intravenous (IV) dose of ceftolozane/tazobactam in pediatric patients with proven/suspected gram-negative infection or receiving perioperative prophylaxis.

RESULTS

Seven patients were enrolled in Group A (birth [7 days postnatal] to < 3 months, > 32 weeks gestation) and six patients were enrolled in Group B (birth [7 days postnatal] to < 3 months, ≤ 32 weeks gestation). PK profiles in neonates and young infants were generally comparable to those of older children receiving a single IV dose of ceftolozane/tazobactam. No serious adverse events (AEs), treatment-related AEs, severe AEs, or clinically significant laboratory abnormalities were reported.

CONCLUSION

Among term and premature neonates and young infants, PK was comparable to older children and ceftolozane/tazobactam was generally well tolerated. An adaptable and flexible study design is necessary for enrollment in neonatal PK trials.

Therapeutic Monitoring of Vancomycin for Serious Methicillin-resistant Staphylococcus aureus Infections: A Revised Consensus Guideline and Review by the American Society of Health-system Pharmacists, the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society, and the Society of Infectious Diseases Pharmacists

Recent clinical data on vancomycin pharmacokinetics and pharmacodynamics suggest a reevaluation of current dosing and monitoring recommendations. The previous 2009 vancomycin consensus guidelines recommend trough monitoring as a surrogate marker for the target area under the curve over 24 hours to minimum inhibitory concentration (AUC/MIC). However, recent data suggest that trough monitoring is associated with higher nephrotoxicity. This document is an executive summary of the new vancomycin consensus guidelines for vancomycin dosing and monitoring. It was developed by the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society, and the Society of Infectious Diseases Pharmacists vancomycin consensus guidelines committee. These consensus guidelines recommend an AUC/MIC ratio of 400-600 mg*hour/L (assuming a broth microdilution MIC of 1 mg/L) to achieve clinical efficacy and ensure safety for patients being treated for serious methicillin-resistant Staphylococcus aureus infections.

Detection of Neisseria gonorrhoeae from Joint Aspirate by Metagenomic Sequencing in Disseminated Gonococcal Infection

Disseminated gonococcal infection (DGI) often manifests as gonococcal arthritis and may carry significant morbidity. However, diagnosis remains elusive due to limited sensitivity of available diagnostic tests. We used metagenomic next-generation sequencing to detect Neisseria gonorrhoeae from culture-negative joint aspirates of 2 patients with clinically diagnosed DGI.

An 11-Year-old Male With X-linked Agammaglobulinemia and Persistent Abdominal Pain

Metagenomic next-generation sequencing is a promising tool for detecting pathogens that are difficult to isolate by traditional modalities, particularly in the diagnosis of complex infections in immunocompromised children. We describe a child with X-linked agammaglobulinemia and chronic abdominal pain diagnosed with a multiorganism infection (Helicobacter cinaedi, Campylobacter coli and Parainfluenza) identified by various diagnostic tools, including plasma metagenomic next-generation sequencing.

Pharmacokinetics and Safety of Single-dose Tedizolid Phosphate in Children 2 to <12 Years of Age

BACKGROUND

Infections with Gram-positive bacteria, including acute bacterial skin and skin structure infections (ABSSSIs), are common in children. We describe a single-dose pharmacokinetics and safety study of tedizolid phosphate, a new oxazolidinone under investigation for the treatment of ABSSSIs in children, in hospitalized participants 2 to <12 years of age.

METHODS

This open-label, multicenter, phase 1 trial (NCT02750761) enrolled hospitalized children 2 to <12 years of age receiving treatment for a confirmed/suspected Gram-positive bacterial infection. Participants were stratified by age (2 to <6 years and 6 to <12 years) to receive a single oral or intravenous dose of tedizolid phosphate. Evaluations included safety and pharmacokinetics of tedizolid phosphate and its active metabolite, tedizolid. Palatability of the oral suspension was also evaluated.

RESULTS

Thirty-two participants were enrolled and received 3-6 mg/kg of study medication. For both routes of administration, tedizolid phosphate was rapidly converted to tedizolid; median time to maximum tedizolid plasma concentration was 1-2 hours after initiation of the 1-hour intravenous infusion and 2-3 hours after oral dosing. The tedizolid mean terminal half-life was 5-6 hours and 6-7 hours for the intravenous and oral administration groups, respectively. The oral tedizolid phosphate suspension demonstrated high bioavailability comparable to that of the parenteral administration. A single dose of intravenous or oral tedizolid phosphate was well tolerated; no unexpected safety findings were observed.

CONCLUSIONS

Pharmacokinetic and safety observations provide the information necessary for the continued development of tedizolid phosphate for the treatment of Gram-positive infections in children, particularly ABSSSIs.

Safety and Efficacy of Oral and/or Intravenous Tedizolid Phosphate From a Randomized Phase 3 Trial in Adolescents With Acute Bacterial Skin and Skin Structure Infections

BACKGROUND

Tedizolid phosphate is an oxazolidinone prodrug approved in 2014 for treatment of adults with acute bacterial skin and skin structure infections (ABSSSIs); however, efficacy has not previously been evaluated in children. This study compared the safety and efficacy of tedizolid (administered as tedizolid phosphate) with active antibacterial comparators for the treatment of ABSSSIs in adolescents.

METHODS

This was a randomized, assessor-blind, global phase 3 study of tedizolid versus active comparators for the treatment of Gram-positive ABSSSIs in adolescents (12 to <18 years of age; NCT02276482). Enrolled participants were stratified by region and randomized 3:1 to receive tedizolid phosphate 200 mg (oral and/or intravenous) once daily for 6 days or active comparator, selected by investigator from an allowed list per local standard of care, for 10 days. The primary endpoint was safety; blinded investigator's assessment of clinical success at the test-of-cure visit (18-25 days after the first dose) was a secondary efficacy endpoint. Statistical comparisons between treatment groups were not performed.

RESULTS

Of the 121 participants enrolled, 120 were treated (tedizolid, n = 91; comparator, n = 29). Treatment-emergent adverse events were balanced between treatment groups (tedizolid, 14.3%; comparator, 10.3%). Overall, 3 participants (3.3%) in the tedizolid group and 1 (3.4%) in the comparator group experienced a single drug-related TEAE. Clinical success rates were high in both treatment groups: 96.7% and 93.1% at the test-of-cure visit for the tedizolid and comparator groups, respectively.

CONCLUSIONS

Tedizolid demonstrated safety and efficacy similar to comparators for the treatment of ABSSSIs in adolescents.

Antimicrobial prescribing for treatment of serious infections caused by Staphylococcus aureus and methicillin-resistant Staphylococcus aureus in pediatrics: an expert review

Introduction: Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), remains a significant pathogen in children. Despite evidence of decreasing prevalence, MRSA bacteremia has been closely associated with complications, including certain infections (i.e. musculoskeletal and endovascular) linked to increased treatment failures.Areas covered: This expert review summarized recent published literature on the role of treatment, dosing and administration of antibiotics used to combat serious S. aureus infections in children. The pertinent antibiotics presented were vancomycin, oxazolidinones, semi-synthetic glycopeptides, daptomycin, tigecycline, novel cephalosporins, fosfomycin and lefamulin. Vancomycin has been the most commonly used antibiotic in empiric therapy for serious MRSA infection, with new key recommendations emphasizing a different approach to dosing and therapeutic monitoring. For other antibiotics, data remain limited or clinical trials are underway.Expert opinion: MRSA remains a significant pathogen in the pediatric population. As numerous therapeutic agents are available, many agents have limited data on usage in pediatric patients. Future studies require pharmacokinetic, safety and efficacy studies in pediatric patients to ensure appropriate therapeutic treatment and outcomes. Phage therapy has been used to treat deep-seated MRSA infections and is an emerging investigational treatment option.

1373. Vaccine Effectiveness and Pneumococcal Serotypes in Pediatric Otitis Media in the Era of Routine 13-valent Pneumococcal Vaccination in the United States

Background

Pneumococcal acute otitis media (AOM) in children due to vaccine related serotypes (St) declined after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13).

Methods

Patients < 18 years with pneumococcal OM isolates from 2014-2019 from the U S Pediatric Multicenter Pneumococcal Surveillance Group were analyzed for demographics, immunization status, antimicrobial susceptibility and St distribution. p< 0.05 was considered statistically significant. Vaccine effectiveness (VE) was calculated using a standard formula: 1-([PCV13St vaccinated (≥3 PCV13 doses) x Non-PCV13St unvaccinated (0-1 PCV13 doses)]/[PCV13St unvaccinated x Non-PCV13St vaccinated])

Results

646 patients were identified. Patients with PCV13 St were older compared to patients with non-PCV13 serotypes (3.3 vs 1.5 median years, p< 0.0001). Most isolates were from spontaneous drainage (71.4 %) and PE tube placements (26.9%). 36 different Sts were identified; 83.4% of isolates were non-PCV13 Sts; 35B represented 18.3% of all isolates. St 19A decreased over time (p=0.0003). 14% of isolates had penicillin MIC ≥2 µg/ml and 2.4% had ceftriaxone MIC >1 µg/ml. (Figure) 633 patients had known vaccine status. VE was 86.4% (Table).

Table.

Conclusion

Non-PCV13 Sts caused most pneumococcal OM. St35B was the most common St. St 19A decreased as a cause of otitis. In this study the VE of≥3 PCV13 doses was 86% for pneumococcal OM.

Disclosures

Tina Q. Tan, MD, Pfizer (Grant/Research Support, Other Financial or Material Support, Chair, DMSB for PCV20 vaccine) Pia S. Pannaraj, MD, MPH, AstraZeneca (Grant/Research Support)Pfizer (Grant/Research Support)Sanofi Pasteur (Advisor or Review Panel member) Sheldon L. Kaplan, MD, Allergan (Research Grant or Support)Pfizer (Grant/Research Support)

176. Selected Impact of the 13-valent Pneumococcal Conjugate Vaccine (PCV13) on Invasive Pneumococcal Disease (IPD) at Eight Children’s Hospitals in the United States. 2014–2019

Background

The 2011 IDSA/PIDS Clinical Practice Guidelines for the Management of Community-acquired Pneumonia (CAP) in Children Older than 3 months recommended empiric treatment with either ampicillin/penicillin or ceftriaxone based on PCV13 vaccine status and the local antibiotic susceptibilities of IPD isolates. No study has addressed differences in antibiotic susceptibilities for isolates from children with pneumococcal pneumonia (PP) based on PCV13 status.

Methods

Investigators from 8 US children’s hospitals identified infants and children with IPD between 1/1/2014 and 12/31/2019. IPD was documented by positive cultures from a normally sterile site. PP diagnosis required an abnormal chest radiograph. Clinical data were recorded and isolates analyzed for serotype (ST) by the capsular swelling method and antimicrobial susceptibilities by standard methods. Administration of PCV7/13 was documented through the patient’s medical records, health care provider or a vaccine registry. Fisher Exact was performed; p&lt; 0.05 was significant.

Results

690 IPD patients with isolates were available (0–18 y); 24% (166/690) of the isolates were PCV13 STs (ST3-75, ST19F-45, ST19A-36, ST7F-5, other STs-5). The most common non-PCV13 ST isolates were ST35B-60, ST23B-59, ST33F-47, ST22F-43, ST15C-35, ST23A-27, ST15B-26, ST10A-26, ST15A-23. Of non-PCV13 isolates, 41% (217/524) were among the 7 additional STs in PCV20. For children with PP (n=157), the distributions of penicillin (Table) (p=0.8) and ceftriaxone MICs were no different for isolates obtained from children regardless of prior PCV13 doses. Less than 7% of PP isolates were resistant to penicillin (MIC &gt;2 µg/mL).

Table. Minimal inhibitory concentrations (MIC) of pneumococcal isolates related to the number of PCV13 doses each patient received prior to pneumococcal pneumonia (PP).

Number of PCV13 doses

Conclusion

PCV13 status should not modify empiric antibiotics for children with suspected pneumococcal CAP. 41% of non-PCV13 IPD isolates were among the 7 additional PCV20 STs.

Disclosures

Sheldon L. Kaplan, MD, Allergan (Research Grant or Support)Pfizer (Grant/Research Support) Tina Q. Tan, MD, Pfizer (Grant/Research Support, Other Financial or Material Support, Chair, DMSB for PCV20 vaccine) Pia S. Pannaraj, MD, MPH, AstraZeneca (Grant/Research Support)Pfizer (Grant/Research Support)Sanofi Pasteur (Advisor or Review Panel member)

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Use of Simulation Strategies to Predict Subtherapeutic Meropenem Exposure Caused by Augmented Renal Clearance in Critically Ill Pediatric Patients With Sepsis

OBJECTIVES

The objectives of this study were to 1) define extent and potential clinical impact of increased or decreased renal elimination of meropenem in children with sepsis, based on analysis of renal function during the first 2 days of PICU stay; and 2) estimate the risk of subtherapeutic meropenem exposure attributable to increased renal clearance.

METHODS

This retrospective study evaluated patients with a diagnosis of sepsis, receiving meropenem from the PICU at Rady Children's Hospital San Diego from 2015-2017. Meropenem exposure was estimated by using FDA-approved doses (20 and 40 mg/kg/dose) on day 1 and day 2 of PICU stay, based on a population pharmacokinetic (PK) model. For this population with sepsis, we assessed time-above-minimum inhibitory concentration (T>MIC) for pathogen MICs.

RESULTS

Meropenem treatment was documented in 105 episodes of sepsis with a 48% rate of pathogen detection. By day 2, increased eGFR (>120 mL/min/1.73 m²) was documented in 49% of patients, with 17% meeting criteria for augmented renal clearance ([ARC] >160 mL/min/1.73 m²) and 10%, for decreased function. Simulations documented that 80% of PICU patients with ARC did not achieve therapeutic meropenem exposure for Pseudomonas aeruginosa with a MIC of 2, using standard doses to achieve a pharmacodynamic goal of 80% T>MIC.

CONCLUSIONS

Approximately 3 of every 20 children with sepsis exhibited ARC during the first 48 hours of PICU stay. Simulations documented an increased risk for subtherapeutic meropenem exposure, suggesting that higher meropenem doses may be required to achieve adequate antibiotic exposure early in the PICU course.

Phase 2 Study of the Safety, Pharmacokinetics and Efficacy of Ceftaroline Fosamil in Neonates and Very Young Infants With Late-onset Sepsis

BACKGROUND

With increasing antimicrobial resistance, antibiotic treatment options for neonatal late-onset sepsis (LOS) are becoming limited. Primary objective of this study was assessment of the safety of ceftaroline fosamil in LOS.

METHODS

Eligible neonates and very young infants 7 to <60 days of age with LOS were enrolled in this phase 2, open-label, multicenter study (NCT02424734) and received ceftaroline fosamil 4 or 6 mg/kg every 8 hours by 1-hour intravenous infusion plus intravenous ampicillin and optional aminoglycoside for 48 hours-14 days. Safety was assessed through the final study visit (21-35 days after the last study therapy dose). Efficacy, assessed as clinical and microbiologic response, was evaluated at end-of-treatment and test-of-cure. Pharmacokinetic samples were collected via sparse-sampling protocol.

RESULTS

Eleven patients [54.5% male, median (range) age 24 (12-53) days] were enrolled and received ceftaroline fosamil for a median (range) duration of 8 (3-15) days. Ten adverse events (AEs) occurred in 5 (45.5%) patients (safety population); most frequent AE was diarrhea (n = 2). All except 1 AE (diarrhea) were nontreatment-related. Predominant baseline pathogen was Escherichia coli. No patients were clinical failures at end-of-treatment/test-of-cure. Observed sparse steady-state pharmacokinetics data (19 samples) were comparable to previous pediatric data and generally within 90% model prediction intervals; neonatal probability of target attainment was >95% based on established pharmacokinetic/pharmacodynamic targets.

CONCLUSIONS

Safety in neonates and very young infants was consistent with the known ceftaroline fosamil safety profile. These results support the use of ceftaroline fosamil (6 mg/kg every 8 hours) as a potential treatment option for LOS.

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

Executive Summary: Therapeutic Monitoring of Vancomycin for Serious Methicillin-Resistant Staphylococcus aureus Infections: A Revised Consensus Guideline and Review of the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society, and the Society of Infectious Diseases Pharmacists

BACKGROUND

Recent vancomycin PK/PD and toxicodynamic studies enable a reassessment of the current dosing and monitoring guideline in an attempt to further optimize the efficacy and safety of vancomycin therapy. The area-under-the-curve to minimum inhibitory concentration (AUC/MIC) has been identified as the most appropriate pharmacokinetic/pharmacodynamic (PK/PD) target for vancomycin. The 2009 vancomycin consenus guidelines recommended specific trough concentrations as a surrogate marker for AUC/MIC. However, more recent toxicodynamic studies have reported an increase in nephrotoxicity associated with trough monitoring.

METHODS AND RESULTS

This is the executive summary of the new vancomycin consensus guidelines for dosing and monitoring vancomycin therapy and was developed by the American Society of Health-Systems Pharmacists, Infectious Diseases Society of America, Pediatric Infectious Diseases Society and the Society of Infectious Diseases Pharmacists vancomycin consensus guidelines committee.

CONCLUSIONS

The recommendations provided in this document are intended to assist the clinician in optimizing vancomycin for the treatment of invasive MRSA infections in adult and pediatric patients. An AUC/MIC by broth microdilution (BMD) ratio of 400 to 600 (assuming MICBMD of 1 mg/L) should be advocated as the target to achieve clinical efficacy while improving patient safety for patients with serious MRSA infections. In such cases, AUC-guided dosing and monitoring is the most accurate and optimal way to manage vancomycin therapy.

Old In Vitro Antimicrobial Breakpoints Are Misleading Stewardship Efforts, Delaying Adoption of Innovative Therapies, and Harming Patients

The current antimicrobial market and old (pre-2000) in vitro antimicrobial susceptibility test interpretative criteria (STIC) are not working properly. Malfunctioning susceptibility breakpoints and antimicrobial markets have serious implications for both patients (ie, from a safety and efficacy perspective) and antibiotic-focused pharmaceutical and biotechnology company economic viability. Poorly functioning STIC fail both patients and clinicians since they do not discriminate between likely effective and ineffective antimicrobial regimens. Poor economic viability fails patients and clinicians as it decreases the industry’s ability to develop antimicrobial agents that clinicians and patients urgently require now and in the future. Herein, we review how STIC for older antimicrobial agents were determined and how their correction can impact the perceived utility of old relative to new antimicrobial agents. Moreover, we describe the data and analysis needs to systematically reevaluate older STIC values. We call for professional infectious diseases societies, government agencies, and other consensus bodies interested in the appropriate use of antimicrobial agents to join an effort to systematically evaluate and, where warranted, correct STIC for all relevant antimicrobial agents. This effort will amplify the effects of other measures designed to increase appropriate antimicrobial use (ie, good antimicrobial stewardship), development, and regulation.

1534. Polymyxin Antimicrobial Susceptibility (AST) Testing and Breakpoints for P. aeruginosa, A. baumannii, and Enterobacteriaceae: Recommendations from the United States Committee on Antimicrobial Susceptibility Testing (USCAST)

Background

Polymyxins are important antimicrobial agents for the treatment of infections due to carbapenem-resistant and other multidrug-resistant organisms. Recently, the CLSI and EUCAST have set breakpoints for colistin (EUCAST and CLSI) and polymyxin B (CLSI) with slight differences in recommendations. However, there are issues unique to the polymyxin class that warrant additional guidances. Herein, we assess data related to breakpoint setting and make additional recommendations for polymyxin AST interpretive criteria.

Methods

Data sources included longitudinal (2011–2017) US surveillance reference broth microdilution (BMD) MIC distributions (128,573 isolates) for colistin and polymyxin B (PB), published data on accuracy of various AST methodologies, in vivo pharmacokinetic/pharmacodynamic (PK-PD) models, prior polymyxin guidelines and agency package insert dosing recommendations, and population PK-PD and toxicodynamic (TD) data. Epidemiological cut-off, PK-PD (and TD), and clinical data were all considered for susceptible (S) breakpoint determinations.

Results

Data demonstrate that the most commonly utilized AST methodologies (disk diffusion, Etest, and automated MIC susceptibility panels), as well as agar dilution testing cannot reliably detect resistance; and BMD is the preferred AST. Importantly, colistin S is a reliable surrogate for PB S with cross-S accuracy at > 99% of isolates in each pathogen group. Breakpoint recommendations can be found in the Table with emphasis on applying combination therapy. Key recommendations include an S breakpoint of ≤2 mg/L for each pathogen (both colistin and PB). However, based on a lack of preclinical efficacy in murine pneumonia models, PK/PD concerns, and poor clinical outcome data, we strongly suggest that no breakpoints are applied for pneumonia and that alternative therapies should be used where available. Additionally, due to a lack of significant renal excretion, PB will also have no S breakpoint recommendation for lower urinary tract infections.

Conclusion

The polymyxins have compromising characteristics that make them suboptimal antimicrobials when used alone, and additional caveats are required for AST breakpoint interpretive criteria and stewardship programs.

Disclosures

All authors: No reported disclosures.

471. Safety and Efficacy of Oral and/or Intravenous Tedizolid Phosphate (TZD) in Adolescents with Acute Bacterial Skin and Skin Structure Tissue Infections (ABSSSI)

Background

Tedizolid phosphate has activity against gram-positive pathogens, including methicillin-resistant Staphylococcus aureus, and was approved for the treatment of ABSSSI in adults in 2014. This study compared the safety and efficacy of TZD with protocol-specified, active comparators for the treatment of ABSSSI in adolescents.

Methods

This was a randomized, assessor-blind, global, multicenter, phase 3 study of TZD vs. active comparator for the treatment of gram-positive ABSSSI in adolescents (aged 12 to < 18 years; NCT02276482). Enrolled patients were stratified by region and randomized 3:1 to TZD 200 mg (IV and/or oral) once daily for 6 days or investigator-selected active comparator per local standard of care (IV vancomycin, linezolid, clindamycin, flucloxacillin, or cefazolin, and/or oral linezolid, clindamycin, flucloxacillin, or cephalexin) for 10 days. The primary endpoint was safety. The percentages of patients with treatment-emergent adverse events (TEAEs) were documented; secondary efficacy endpoints included the blinded investigator’s assessment of clinical success at a test of cure visit (18–25 days after start of dosing) and early clinical response (≥20% reduction from baseline lesion area) at 48–72 h. No hypothesis testing was planned for the treatment groups.

Results

Of the 121 patients enrolled, 120 were treated (TZD, N = 91; comparator, N = 29). Median (range) age was 15 (12–17) years. Most patients were male (62.5%), white (86.7%), and enrolled in Europe (78.3%). Infections included major cutaneous abscess (42.5%), cellulitis/erysipelas (40.0%), and infected wound (17.5%). At baseline, the median (range) lesion surface area was 82.1 (14–978) cm2. Of those with gram-positive cultures (n = 64), S. aureus was most frequently isolated (n = 55 [85.9%]) with 3 isolates (4.7%) being methicillin resistant. TZD was well tolerated, and TEAEs were balanced between treatment arms (TZD, 14.3%; comparator, 10.3%). A total of 3 (3.3%) patients in the TZD group and 1 (3.4%) in the comparator group experienced a single-drug-related TEAE. Clinical success rates were high and similar between treatment groups (table).

Conclusion

TZD demonstrated comparable safety and efficacy to comparator in the treatment of ABSSSI in adolescents.

Disclosures

All authors: No reported disclosures.

2707. Non 13-Valent Pneumococcal Conjugate Vaccine Serotypes Predominate as Causes of Pneumococcal Otitis Media in Children

Background

Pneumococcal acute otitis media (AOM) in children due to vaccine-related serotypes (ST) has declined after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13), although some serotypes, such has 3, 19A and 19F have persisted. Among non-vaccine serotypes, 35B has been shown to contribute substantially to both OM and invasive infections. This study describes the current epidemiology of pneumococcal OM isolates obtained from the U S Pediatric Multicenter Pneumococcal Surveillance Group (USPMPSG).

Methods

From the USPMPSG database, we collected data from patients <18 years of age with pneumococcal OM isolates from 2014 to 2018. Analysis included demographics, immunization status, antimicrobial susceptibility data and serotype. Statistical comparisons included Fisher’s exact and Wilcoxon rank-sum tests.

Results

A total of 494 patients with isolates were identified within the time period from 5 children’s hospitals. Median age was 1.7 years (range 0–17.6) and 299 (60.5%) were male; 176 (35.7%) had an underlying condition. Thirty-two patients had received no dose of either PCV7 or PCV13. Thirty-five serotypes were identified (3 isolates were non-typeable), of which 6 serotypes [35B (16.8%), 3 (9.5%), 15A (7.9%), 15B (7.9%), 23B (7.9%) and 21 (6.1%)] caused more than half of the total OM infections (figure). Ninety (18.2%) isolates were of PCV13 serotypes. Twenty-five of 476 (5.3%) isolates had a penicillin MIC>2 µg/mL. These were of serotypes 11A, 15A/C, 19A/F, 35B and NT; 10/455 (2.2%) isolates had ceftriaxone MIC>1 µg/mL and were of ST 3, 15A, 19A/F and 35B.

Conclusion

Most pneumococcal OM were caused by non-PCV13 serotypes. Serotype 35B remained the most common serotype among pneumococcal isolates recovered from ear drainage or middle ear cultures. The low proportion of penicillin-resistant isolates along with the increasing proportion of AOM cases being due to non-pneumococcal isolates supports the consideration to switch routine antibiotic treatment for AOM to standard dose amoxicillin-clavulanate from high dose amoxicillin in PCV13 immunized children (Pediatr Infect Dis J 2018;37:1255–1257).

Disclosures

All authors: No reported disclosures.

1590. Updated Aminoglycoside (AG) MIC Breakpoints (BP) to Minimize Adverse Events and Improve Outcome: Impact on Susceptibility (S) Rates

Background

In 2016 USCAST, the National Advisory Committee (NAC) for the United States (US) to EUCAST, undertook the re-evaluation of the in vitro susceptibility (AST) test interpretive criteria (IC) for gentamicin (GM), tobramycin (TO) and amikacin (AK) against Enterobacteriaceae (ENT), P. aeruginosa (PSA) and S. aureus (SA) based on an analysis of contemporary microbiology and PK/PD data. In 2019 USCAST posted the third version (www.uscast.org) of AG IC document and CLSI and EUCAST has published AG IC in CLSI M100-S29 and EUCAST v 9.0 documents. USCAST ICs for S were generally lower than those proposed by CLSI for all organism/drug combinations. PK/PD emphasized high, extended interval dosing (5 renal function groups) to reduce nephro-vestibular toxicity and a stasis exposure endpoint. Here, we evaluate the impact on S rates for US AST data that these IC changes created.

Methods

Clinical isolates from 2010 to 2018 US SENTRY Program (reference broth microdilution AST) were analyzed for S based on current and previous IC values. AG results for GM, TO and AK were evaluated against 66,280 ENT, 13,959 PSA and 51,950 SA. Benchmark S data for meropenem, cefepime, piperacillin–tazobactam and new AG, plazomicin (PZM) were included as well as ESBL and carbapenem-resistant ENT (CRE; 805 isolates).

Results

S rates for ENT as determined by USCAST IC were reduced by 4.2/1.2/3.1% for AK/GM/TO (CLSI) and by 3.3% for AK (EUCAST); no S rate difference for GM and TO as determined by USCAST/EUCAST. For PSA, S decreased by 46.8/6.2% for AK/TO (EUCAST) and 51.6/6.2% (CLSI). S for SA vs. GM declined by only 0.2% (CLSI). No AG IC could be calculated/offered for Acinetobacter or GM X PSA or AM/TO X SA. Best S overall coverage X ESBL (99.2%) or CRE (97.2%) isolates was by PZM.

Conclusion

USCAST IC updates for AG lead to reduced values for some organism/drug combinations among ENT and PSA compared with those proposed elsewhere. The USCAST-recommended ICs were based on achieving AUC/MIC ratio target associated with net bacterial stasis. Given the assumption of AG combination therapy, stasis was considered a reasonable endpoint when evaluating AG ICs to improve both safety and efficacy. Some organism X drug exposures could not be calculated and lower IC for pneumonia isolates (GM, TO) was recommended.

Disclosures

All authors: No reported disclosures.