1591. Updated Fluoroquinolone MIC Breakpoints: Impact on Susceptibility Rates in the United States

Background

In 2015 USCAST, the National Advisory Committee for the United States (US) to EUCAST, produced a report (Version 1.0) on their website (www.uscast.org) re-evaluating fluoroquinolone (FQ) breakpoint interpretive criteria (IC) based on analysis of current microbiology and pharmacokinetic/pharmacodynamic (PK/PD) data. EUCAST initiated a consultative process using USCAST analyses in an effort to update FQ IC, released in 2017. CLSI formed an ad-hoc working group in late 2015 to review the USCAST FQ document and formulate questions about content. In 2018, USCAST released V1.3 of the FQ document and CLSI subsequently published updated FQ MIC IC in the M100-S29 (2019) document. This study evaluated the impact on susceptibility (S) rates for US surveillance data that these IC changes created.

Methods

Clinical isolates (reference broth microdilution MIC) from 2016–2018 US SENTRY Program were analyzed for S based on current and previous IC. FQ results for ciprofloxacin (CIP), levofloxacin (LEV), and moxifloxacin (MOX) were evaluated. Benchmark S comparison data for meropenem, cefepime, piperacillin–tazobactam and delafloxacin (new FQ) were also included.

Results

S rates for Enterobacteriaceae (ENT;Figure) were reduced by 3.8/3.7% for CIP/LEV (CLSI) and 2.3/2.5% (EUCAST). MOX-S rate vs. ENT declined 5.7% (EUCAST). Although reductions in S occurred for most organism groups, K. pneumoniae (6.0/5.5% for CIP/LEV [CLSI] and 4.0/4.2% [EUCAST]) and S. marcescens (7.4/4.1% for CIP/LEV [CLSI] and 4.1/5.0% [EUCAST]) reductions were among the largest changes. For Pseudomonas aeruginosa (PSA), CIP-S decreased 6.8% and LEV-S 10.1% (CLSI); but potential for false-S results remain using CLSI IC (5 pathogens).

Conclusion

USCAST’s comprehensive analyses of FQ IC in 2015 led to revised breakpoints for most organism/drug combinations among ENT and PSA compared with those being used before. USCAST analysis was most influenced by PK/PD in vivo data as current clinical outcomes data by MIC was limited. Awareness and interactions (both formal and informal) among breakpoint setting organizations has modified FQ ICs which are lower than previously recommended, and although not perfectly harmonized in time and detail, this represents a successful model.

Disclosures

All authors: No reported disclosures.

Optimizing Antibiotic Drug Therapy in Pediatrics: Current State and Future Needs

The selection of the right antibiotic and right dose necessitates clinicians understand the contribution of pharmacokinetic variability stemming from age-related physiologic maturation and the pharmacodynamics to optimize drug exposure for clinical response. The complexity of selecting the right dose arises from the multiplicity of pediatric age groups, from premature neonates to adolescents. Body size and age (which relate to organ function) must be incorporated to optimize antibiotic dosing in this vulnerable population. In the effort to optimize and individualize drug dosing regimens, clinical pharmacometrics that incorporate population-based pharmacokinetic modeling, Bayesian estimation, and Monte Carlo simulations are utilized as a quantitative approach to understanding and predicting the pharmacology and clinical and microbiologic efficacy of antibiotics. In addition, opportunistic study designs and alternative blood sampling strategies can serve as practical approaches to ensure successful conduct of pediatric studies. This review article examines relevant literature on optimization of antibiotic pharmacotherapy in pediatric populations published within the last decade. Specific pediatric antibiotic data, including beta-lactam antibiotics, aminoglycosides, and vancomycin, are critically evaluated.

Invasive Pneumococcal Disease in Children's Hospitals: 2014-2017

BACKGROUND

The 13-valent pneumococcal conjugate vaccine (PCV13) was licensed in the United States in 2010. We describe invasive pneumococcal disease (IPD) in children at 8 children's hospitals in the US from 2014 to 2017.

METHODS

Children with IPD occurring from 2014 to 2017 were identified from a prospective study. Demographic and clinical data, including results of any immune evaluation along with the number and dates of previous pneumococcal conjugate vaccines administered, were recorded on case report forms. Isolate serotypes were determined in a central laboratory. Pneumococcal conjugate vaccine doses were counted if IPD occurred ≥2 weeks after a dose.

RESULTS

PCV13 serotypes accounted for 23.9% (115 out of 482) of IPD isolates from 2014 to 2017. Serotypes 3, 19A, and 19F accounted for 91% of PCV13 serotypes. The most common non-PCV13 serotypes were 35B, 23B, 33F, and 22F. An underlying condition was significantly (P < .0001) more common in children with IPD due to non-PCV13 serotypes (200 out of 367, 54.5%) than for children with PCV13 serotypes (27 out of 115, 23.5%). An immune evaluation was undertaken in 28 children who received ≥2 PCV13 doses before IPD caused by a PCV13 serotype. Only 1 was found to have an immunodeficiency.

CONCLUSIONS

PCV13 serotypes (especially serotypes 3, 19A, and 19F) continue to account for nearly a quarter of IPD in US children 4 to 7 years after PCV13 was introduced. Underlying conditions are more common in children with non-PCV13 serotype IPD. Immune evaluations in otherwise healthy children with PCV13 serotype IPD despite receiving ≥2 PCV13 doses did not identify an immunodeficiency.

A non-randomized trial to assess the safety, tolerability, and pharmacokinetics of posaconazole oral suspension in immunocompromised children with neutropenia

Background

Posaconazole (POS) is a potent triazole antifungal agent approved in adults for treatment and prophylaxis of invasive fungal infections (IFIs). The objectives of this study were to evaluate the pharmacokinetics (PK), safety, and tolerability of POS oral suspension in pediatric subjects with neutropenia.

Methods

This was a prospective, multicenter, sequential dose-escalation study. Enrolled subjects were divided into 3 age groups: AG1, 7 to <18 years; AG2, 2 to <7 years; and AG3, 3 months to <2 years. AG1 and AG2 were divided into 3 dosage cohorts: DC1, 12 mg/kg/day divided twice daily (BID); DC2, 18 mg/kg/day BID; and DC3, 18 mg/kg/day divided thrice daily (TID). AG3 was also divided into DC1 and DC2; however, no subjects were enrolled in DC2. Subjects received 7–28 days of POS oral suspension. PK samples were collected at predefined time points. The POS PK target was predefined as ~90% of subjects with C_avg (AUC /dosing interval) between 500 and 2500 ng/mL, with an anticipated mean steady state C_avg exposure of ~1200 ng/mL.

Results

The percentage of subjects meeting the PK target was <90% across all age groups and dosage cohorts (range: 31% to 80%). The percentage of subjects that achieved the C_avg target of 500 to 2500 ng/mL on Day 7 ranged from 31% to 80%, with the lowest proportion in subjects 2 to <7 years receiving 12 mg/kg/day BID (AG2/DC1) and the highest proportion in subjects 7 to <18 years receiving 18 mg/kg/day TID (AG1/DC3). At all three dose levels (12 mg/kg/day BID, 18 mg/kg/day BID and 18 mg/kg/day TID), subjects in AG1 (7 to <18 years old) had higher mean PK exposures at steady state than those in AG2. High variability in exposures was observed in all groups. POS oral suspension was generally well tolerated and most of the reported adverse events were related to the subjects’ underlying diseases.

Conclusion

The POS PK target of 90% of subjects with C_avg between 500 and 2500 ng/mL was not achieved in any of the age groups across the different dosage cohorts. New formulations of the molecule with a greater potential to achieve the established PK target are currently under investigation.

Trial registration

ClinicalTrials.gov identifier: NCT01716234

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.

Community-acquired pneumonia in children: cell-free plasma sequencing for diagnosis and management

Community-acquired pneumonia (CAP) is a common cause of pediatric hospital admission. Empiric antibiotic therapy for hospitalized children with serious CAP now targets the most likely pathogen(s), including those that may demonstrate significant antibiotic resistance. Cell-free plasma next-generation sequencing (CFPNGS) was first made available for Pediatric Infectious Diseases physicians in June 1, 2017, to supplement standard-of-care diagnostic techniques. A retrospective chart review was performed for children hospitalized with CAP between June 1, 2017, and January 22, 2018, to evaluate the impact of CFPNGS. We identified 15 hospitalized children with CAP without other underlying medical conditions for whom CFPNGS was performed. CFPNGS identified a pathogen in 13 of 15 (86%) children compared with 47% for those using standard culture and PCR-based methods alone. Changes in antibiotic management were made in 7 of 15 (47%) of children as a result of CFPNGS.

2562. Re-Appraisal of Aminoglycoside (AG) Susceptibility Testing Breakpoints Based on the Application of Pharmacokinetics–Pharmacodynamics (PK-PD) and Contemporary Microbiology Surveillance Data

Background

Resistance to AGs and numerous other classes continues to emerge. To ensure that susceptibility is accurately characterized and that clinicians have reliable data to select effective agents, appropriate in vitro susceptibility testing interpretive criteria (susceptible breakpoints [BKPTs]) are crucial to ensure optimal patient care. Recently, USCAST, the USA voice to EUCAST/EMA, evaluated the BKPTs for the 3 most commonly used AGs, gentamicin, tobramycin, and amikacin [Bhavnani et al., IDWeek 2016; P-1977]. As a result of consultation from interested parties, which included evaluating AG dosing regimens provided in the US-FDA product package inserts and simulated patients with varying creatinine clearance, these BKPTS were reassessed.

Methods

Data sources considered included longitudinal US reference MIC distributions using in vitro surveillance data collected over 18 years, QC performance (MIC, disk diffusion), population pharmacokinetics (PK), and in vivo PK-PD models. Using population PK models, PK-PD targets for efficacy and Monte Carlo simulation, percent probabilities of PK-PD target attainment by MIC after administration of traditional and extended interval AG dosing regimens were evaluated among simulated patients. Epidemiological cut-off and PK-PD BKPTs were considered when recommending BKPTs for AG–pathogen pairs.

Results

An example of PK-PD target attainment analysis output is provided in Figure 1 and a subset of recommended AG BKPTs for 3 pathogens is shown in Table 1. Updated USCAST BKPTs, which were based on the application of population PK and PK-PD models, simulation techniques, and contemporary MIC distribution statistics, are generally lower than those of EUCAST/EMA, USA-FDA, and CLSI. Adequate PK-PD target attainment was not achieved for some AG-pathogen pairs, even when high-dose AG dosing regimens and PK-PD targets for stasis were evaluated (e.g., gentamicin vs. P. aeruginosa; amikacin vs. S. aureus).

Conclusion

These revised AG BKPT recommendations, which will be made freely available to EUCAST, USA-FDA, and CLSI, will be finalized after considering comments from additional interested stakeholders. This process will be followed in an effort to bring harmonization to global BKPTs for AGs.

Disclosures

All authors: No reported disclosures.

Invasive Pneumococcal Disease in Infants Aged 0-60 Days in the United States in the 13-Valent Pneumococcal Conjugate Vaccine Era

We identified 53 infants aged 0-60 days with invasive pneumococcal disease (IPD) at 8 children's hospitals in the United States (2005-2015). After the introduction of 13-valent pneumococcal conjugate vaccine (PCV13), IPD caused by PCV13 serotypes decreased ~30% providing some evidence of indirect protection. However, approximately 60% of IPD was still caused by PCV13 serotypes.

Extensive orf infection in a toddler with associated id reaction

Orf is a zoonotic parapoxvirus typically transmitted to humans by a bite from goats or sheep. We present an unusual case of multiple orf lesions on the fingers of a 13-month-old child who was bitten by a goat and subsequently developed progressive swelling, blistering, and necrotic papulonodules of the hand followed by an additional diffuse, pruritic, papular rash. A primary diagnosis of orf infection was confirmed using real-time polymerase chain reaction, and the diffuse eruption was clinically consistent with an id reaction. Extensive necrosis and papular id reaction associated with orf rarely have been described.

Pharmacokinetics of single-dose ceftaroline fosamil in children with cystic fibrosis

BACKGROUND

Single-dose pharmacokinetics (PK) and safety of ceftaroline fosamil with population pharmacokinetic/pharmacodynamic (PK/PD) modeling for staphylococcal pneumonia was performed in children with CF.

METHODS

Subjects between 6 and 18 years old were evaluated in this phase 1, open-label, single-dose, prospective study using 10 mg/kg (up to 600 mg). Non-compartmental analysis and population-based PK analyses with Monte Carlo simulation (for doses 8-20 mg/kg every 8 h, infused over 1-4 h) were conducted.

RESULTS

A total of 20 subjects were enrolled. The median age and weight were 12 yr (range 6.3-17.4) and 38.7 kg (range 17.8-94.3), respectively. A 3-compartment linear model incorporating age and weight provided the best fit for the data. Comparing children 6 to <12 years to those 12 to <18 years, the mean posthoc Bayesian parameter estimates for total volume of distribution (VT ) were 0.32 ± 0.05 L/kg versus 0.32 ± 0.04 L/kg, P = 0.7; and total Clearance (CLT ), 0.50 ± 0.10 L/h/kg versus 0.30 ± 0.07 L/h/kg, P = 0.001. Using susceptibility data from pediatric MRSA lower respiratory tract isolates, 8 mg/kg (maximum of 1000 mg per dose) infused over 1 h every 8 h achieved free-drug plasma concentrations above the minimum inhibitory concentration for ≥60% of the dosing interval in at least 95% of virtual subjects.

CONCLUSIONS

Since children with CF have increased ceftaroline CL compared with published data from non-CF children; greater dosages may be required in children with CF to achieve adequate exposure in the treatment of MRSA pneumonia. Pharmacodynamic-based dosing predicts that dosing should also be based on the patient's MRSA MIC.

Intravenous Zanamivir in Hospitalized Patients With Influenza

BACKGROUND

Children with severe influenza infection may require parenteral therapy if oral or inhaled therapies are ineffective or cannot be administered. Results from a study investigating intravenous (IV) zanamivir for the treatment of hospitalized infants and children with influenza are presented.

METHODS

This phase II, open-label, multicenter, single-arm study assessed the safety of investigational IV zanamivir in hospitalized children with influenza. Safety outcomes included treatment-emergent adverse events (TEAEs), clinical laboratory measurements, and vital signs. Clinical outcomes, pharmacokinetics, and virologic efficacy data were collected as key secondary outcomes.

RESULTS

In total, 71 children received treatment with investigational IV zanamivir (exposure comparable to 600 mg twice daily in adults). TEAEs and serious TEAEs (STEAEs) were reported in 51 (72%) and 15 (21%) patients, respectively. The mortality rate was 7%, and median durations of hospital and ICU stays were 6 and 7.5 days, respectively. No STEAEs or deaths were considered related to IV zanamivir treatment, and no patterns of TEAEs, laboratory abnormalities, or vital signs were observed. The mean zanamivir exposures from 34 patients with normal renal function who received 12 mg/kg, 14 mg/kg, or 600 mg of IV zanamivir ranged from 64.5 to 110 hour·µg/mL. The median change from baseline in the viral load was -1.81 log₁₀ copies per mL after 2 days of treatment.

CONCLUSIONS

The safety profile of IV zanamivir was favorable, with no drug-related STEAEs reported. The majority of children experienced virologic response and clinical improvement during the treatment course. Systemic zanamivir exposures in children were consistent with adults.

Low Infection-Related Re-Admission Rates in a Retrospective of 4725 Children with Appendicitis Using a Clinical Pathway in a Tertiary Care Pediatric Center

BACKGROUND

Standardization of antibiotic management of appendicitis in tertiary care pediatric centers has been associated with improved outcomes. Rady Children's Hospital-San Diego implemented an appendicitis clinical pathway in 2005. We evaluated infection-related re-admission risk factors since 2010, when an electronic medical record was established, with the aim to optimize the clinical pathway.

METHODS

Between January 2010 and August 2015, 4725 children with a diagnosis of appendicitis were evaluated for demographic data, pathology diagnoses, culture results, and inpatient and oral step-down antibiotic therapy regimens. From children originally admitted for appendicitis, those who were re-admitted with infection were compared with those who were not re-admitted for infection. The populations were controlled by severity of infection using a pathology-defined appendicitis severity scale: Grade 0, no appendicitis; grade 1, simple acute appendicitis with gross and microscopic evidence of inflammation, but no perforation; grade 2, gangrenous/necrotizing/micro-perforated appendicitis with subserosal or serosal exudate, but no frank or visually appreciated perforation; and grade 3, frank perforation.

RESULTS

Of 4725 children (total population, TP) admitted with a diagnosis of appendicitis, only 199 (4.2%) were re-admitted, with 125 of these admissions for infection (2.65% of the TP). Age, race/ethnicity, language preference, and body mass index were not found to correlate with re-admission for infection. Length of stay significantly differed between the no infection-related re-admission population and infection-related re-admission population (3.02 vs. 4.03 d, p < 0.001). There was a trend toward higher infection-re-admission rates as the pathology grade increased (odds ratio grade 1 vs. grade 3 = 2.28, 95% confidence interval 1.03, 5.03).

CONCLUSIONS

Infection-related re-admission rates for children on the clinical pathway in our institution were infrequent. The greater association of all-cause and infection-related re-admission rates with pathology grade suggest that defining appendicitis by pathology and clinical severity may provide an evidence-based scoring system to support clinical observation in the use and duration of antibiotic therapy.

Global shortage of neonatal and paediatric antibiotic trials: rapid review

OBJECTIVES

There have been few clinical trials (CTs) on antibiotics that inform neonatal and paediatric drug labelling. The rate of unlicensed and off-label prescribing in paediatrics remains high. It is unclear whether the current neonatal and paediatric antibiotic research pipeline is adequate to inform optimal drug dosing. Using the ClinicalTrials.gov registry, this review aims to establish the current global status of antibiotic CTs in children up to 18 years of age.

METHODS

Studies were identified using key word searches of the ClinicalTrials.gov registry and were manually filtered using prespecified inclusion/exclusion criteria.

RESULTS

76 registered open CTs of antibiotics in children were identified globally; 23 (30%) were recruiting newborns (only 8 (11%) included preterm neonates), 52 (68%) infants and toddlers, 58 (76%) children and 54 (71%) adolescents. The majority of registered trials were late phase (10 (15%) phase 3 and 23 (35%) phase 4/pharmacovigilance). Two-thirds were sponsored by non-profit organisations, compared with pharmaceutical companies (50 (66%) vs 26 (34%), respectively). A greater proportion of non-profit funded trials were efficacy-based strategic trials (n=34, 68%), in comparison with industry-led trials, which were most often focused on safety or pharmacokinetic data (n=17, 65%). Only 2 of the 37 antibiotics listed on the May 2016 Pew Charitable Trusts antibiotic development pipeline, currently being studied in adults, appear to be currently recruiting in open paediatric CTs.

CONCLUSIONS

This review highlights that very few paediatric antibiotic CTs are being conducted globally, especially in neonates. There is a striking disparity noted between antibiotic drug development programmes in adults and children.

Plasma Pharmacokinetics of Ceftolozane/Tazobactam in Pediatric Subjects with Cystic Fibrosis

Background

Ceftolozane/tazobactam (TOL/TAZ), a novel anti-pseudomonal cephalosporin/β-lactamase inhibitor combination, is approved for the treatment of complicated intra-abdominal infections (cIAI) and urinary tract infections (cUTI) in adults. TOL/TAZ has potent activity against Gram-negative pathogens associated with pulmonary infections in cystic fibrosis (CF). Limited data exists on the pharmacokinetics (PK) of TOL/TAZ in the CF population. The aim of this analysis is to evaluate plasma PK parameters in CF and non-CF pediatric subjects to assess whether CF alters the PK of TOL/TAZ.

Methods

Nine subjects with CF were enrolled in the 2 to &lt;18 y old cohort of an ongoing Phase 1 PK study of a single dose of intravenous TOL/TAZ in pediatric subjects with suspected or proven Gram-negative infection (NCT02266706). Population PK models for TOL and TAZ were developed using PK data from 12 adult studies and preliminary PK data from pediatric subjects. An exploratory analysis comparing model-derived plasma TOL and TAZ PK parameters between CF (N = 9) and non-CF (N = 9) pediatric subjects was conducted.

Results

Mean (range) age and weight of the 9 CF subjects were 11.4 y (5.5–17.5 y) and 37.4 kg (17.4–60 kg), respectively. For TOL, the mean (SD) systemic clearance (CL) normalized by weight was 0.16 (0.03) and 0.15 (0.03) L/hours/kg in CF and non-CF subjects, respectively, suggesting no difference in CL; similar observations were made for volume of the central compartment normalized by weight. All subjects achieved the plasma PK/pharmacodynamic (PD) target of %fT&gt;MIC of at least 30% for an MIC of 4 µg/mL.

Differences in weight-normalized CL were more pronounced for TAZ in CF and non-CF subjects (mean [SD]: 0.73 [0.25], 0.42 [0.13] L/hours/kg, respectively). However, the half-life was similar in CF and non-CF subjects (mean [SD]: 0.99 [0.15] hours, 1.08 [0.15] hours, respectively), suggesting that differences are unlikely to be clinically meaningful. At the recommended dose being advanced into Phase 2, subjects are projected to achieve the TAZ plasma PK/PD target of %fT&gt;threshold concentration (Ct) of &gt;20% for a Ct of 1 µg/mL.

Conclusion

Preliminary exploratory analysis of TOL/TAZ PK in a small group of pediatric patients supports evaluation of the same TOL/TAZ dose in children with and without CF in future clinical studies.

Disclosures

K. Larson, Merck: Employee, Salary. S. Yang, Merck: Employee, Salary.; B. Yu, Merck: Employee, Salary. M. G. Johnson, Merck: Employee, Salary. M. Rizk, Merck: Employee, Salary. E. Rhee, Merck: Employee, Salary.

Analysis of Invasive Pneumococcal Infections Due to 13-Pneumococcal Conjugate Vaccine Serotypes at 8 US Children’s Hospitals During 2014 to 2016

Background

The 13-Valent Pneumococcal Conjugate Vaccine (PCV13) was licensed in 2010 and is directed against serotypes (ST) 1,3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F. Details of cases of invasive pneumococcal disease (IPD) due to PCV13 ST since 2010 in the US are sparse. We describe IPD cases due to PCV13 ST seen at 8 US children’s hospitals over years 2014 to 2016 which may aid in understanding why some IPD cases due to these ST have persisted.

Methods

Children with IPD have been prospectively identified at 8 children’s hospitals in the US since 1993. Data from 2014 through 2016 were analyzed. Demographic, clinical data and number and dates of PCV doses were collected on case report forms and isolates were sent to a central laboratory for serotyping. PCV doses are counted if IPD occurred &gt; 2 weeks after a dose.

Results

PCV13 ST accounted for 19.7% (27/137), 26.8% (30/112) and 26% (33/127) of IPD cases in 2014, 2015 and 2016, respectively. ST 3, 19A and 19F accounted for 90% of the PCV13 ST IPD cases. &gt;50% of the children had received ≤2 doses of PCV13 prior to IPD. (Table) Of the 30 children with 0 doses of PCV, 15 were of an age at diagnosis for which ≥ 2 doses of PCV was recommended. An underlying condition was noted in 18. For PCV13 ST, the types of IPD were pneumonia (n = 39), mastoiditis (n = 15), bacteremia (n = 15), meningitis (n = 12) and other sites of infection (n = 9). Whereas the numbers of yearly cases were similar for ST3 (12, 10, 13) and ST19A (8, 10, 6), the numbers for 19F increased slightly (3, 8, 10).

Conclusion

Four to 6 years after PCV13 was introduced, PCV13 ST (especially ST 3, 19A and 19F) accounted for about 25% of IPD in children. For all of the PCV13 ST, over half of these IPD cases occurred in children who had received ≤ 2 doses of the recommended PCV schedule; 25% of cases occurred in children who had not received any doses but were of the age at diagnosis that at least 2 PCV doses should have been received. Additional PCV13 ST IPD cases may be preventable if the PCV13 schedule is followed as recommended.

Disclosures

S. L. Kaplan, Pfizer: Grant Investigator and Speaker at PCV13 Launch Meeting in China, Research grant and Speaker honorarium; J. S. Bradley, Merck & Co., Inc.: Investigator, Research support

Dalbavancin Pharmacokinetics and Safety in Children 3 Months to 11 Years of Age

BACKGROUND

Dalbavancin is a novel lipoglycopeptide antibiotic that has potent in vitro activity against Gram-positive microorganisms.

METHODS

We performed a phase 1, open-label, multicenter study to investigate the pharmacokinetics (PK) and safety of a single dose of intravenous dalbavancin in hospitalized pediatric subjects 3 months to 11 years of age. We combined these data with previously collected adolescent PK data and performed a population PK analysis.

RESULTS

Model development was performed using 311 dalbavancin plasma concentrations from 43 subjects. The median age was 5.9 years (range: 0.3-16.9). A 3-compartment, linear PK model was developed. Based on simulations, the following age-dependent dosing regimen was found to achieve similar dalbavancin exposure to that in adults administered a 2-dose regimen: children 6 to <18 years of age, 12 mg/kg (1000 mg maximum) on day 1 and 6 mg/kg (500 mg maximum) on day 8 and children 3 months to <6 years of age, 15 mg/kg (1000 mg maximum) on day 1 and 7.5 mg/kg (500 mg maximum) on day 8. Similarly, the following age-dependent regimen was found to match adult exposure after a single-dose (1500 mg): 6 to <18 years of age, 18 mg/kg (1500 mg maximum) on day 1 and 3 months to <6 years of age, 22.5 mg/kg (1500 mg maximum) on day 1. Nineteen subjects experienced 36 treatment-emergent adverse events. Five of 36 adverse events were assessed as possibly or probably related to treatment.

CONCLUSIONS

Dalbavancin pediatric dosing that matched adult exposure was identified. Overall, dalbavancin was well tolerated in our study population.

Population PK Modeling and Target Attainment Simulations to Support Dosing of Ceftaroline Fosamil in Pediatric Patients With Acute Bacterial Skin and Skin Structure Infections and Community-Acquired Bacterial Pneumonia

Ceftaroline, the active form of the prodrug ceftaroline fosamil, is approved for use in adults with community-acquired bacterial pneumonia (CABP) or acute bacterial skin and skin structure infections (ABSSSI) in the United States and for similar indications in Europe. Pharmacokinetic (PK) data from 5 pediatric (birth to <18 years) studies of ceftaroline fosamil were combined with PK data from adults to update a population PK model for ceftaroline and ceftaroline fosamil. This model, based on a data set including 305 children, was used to conduct simulations to estimate ceftaroline exposures and percentage of time that free drug concentrations were above the minimum inhibitory concentration (%fT>MIC) for pediatric dose regimens. With dose regimens of 8 mg/kg every 8 hours (q8h) in children aged 2 months to <2 years and 12 mg/kg (up to a maximum of 400 mg) q8h in children aged 2 years to <18 years or 600 mg q12h in children aged 12 to <18 years, >90% of children were predicted to achieve a target of 36% fT>MIC at an MIC of 2 mg/L, and >97% were predicted to achieve 44% fT>MIC at an MIC of 1 mg/L. Thus, high PK/pharmacodynamic target attainment would be maintained in children for targets associated with 1-log kill of Staphylococcus aureus and Streptococcus pneumoniae. The predicted ceftaroline exposures for these dose regimens were similar to those in adults given 600 mg q12h ceftaroline fosamil. This work contributed to the approval of dose regimens for children aged 2 months to <18 years by the FDA and EMA, which are presented.

Invasive pneumococcal infections in children following transplantation in the pneumococcal conjugate vaccine era

BACKGROUND

Pediatric recipients of hematopoietic stem cell and solid organ transplants are at increased risk of invasive pneumococcal infections (IPI). Data on IPI in this population are scarce. To our knowledge, this is the first study describing the epidemiology of IPI among pediatric transplant recipients in the pneumococcal conjugate vaccine (PCV) era.

METHODS

We identified transplant recipients with IPI at 8 children's hospitals in the U.S. from our surveillance database (2000-2014). Pneumococcal isolates were collected prospectively. Serotyping and antibiotic susceptibility were performed in a central laboratory. Categorical variables were analyzed by Fisher's exact test and continuous variables with nonparametric tests. Indirect cohort study design was used to calculate vaccine effectiveness.

RESULTS

We identified 65 episodes of IPI in transplant recipients. Recurrent IPI was observed in 10% of transplant recipients. The IPI crude incidence rate in solid organ transplant recipients was higher than in the general population. Most IPI episodes occurred >6 months after transplantation. Bacteremia and pneumonia were the most common presentations. Meningitis was unusual. No case fatalities were observed. Serotype 19A was the most common serotype (n=10), followed by 6C (n=7). In 2010-2014, 37% of IPI was caused by PCV13 serotypes. Four cases of vaccine breakthrough were identified. Most isolates were susceptible to penicillin and ceftriaxone. Pneumococcal conjugate and polysaccharide immunization rates were low.

CONCLUSION

Pediatric transplant recipients remain at increased risk of IPI in the vaccine era. Most cases presented as a late post-transplant infection. The interval between transplantation and IPI may allow adequate time for pneumococcal immunization.

Carbon Fibre Reinforced Plastics for Load-Bearing Implants

Work is currently in progress concerning two distinct groups of carbon fibre composites for orthopaedic implants. This paper will emphasize the work on carbon fibre reinforced ultra high molecular weight polyethylene for which preliminary results have been reported (Bradley and Evans, 1977). Carbon fibre reinforced epoxy will be referred to only briefly owing to publication elsewhere (Bradley et al, 1980).

Plane of nutrition affects growth rate, organ size and skeletal muscle satellite cell activity in newborn calves

Plane of nutrition effects on body, tissue and cellular growth in the neonatal calf are poorly understood. The hypothesis that a low plane of nutrition (LPN) would limit skeletal muscle size by reducing fibre growth and muscle progenitor cell activity was tested. At birth, calves were randomly assigned to either a LPN (20% CP, 20% fat; GE=1.9 Mcal/days) or a high plane of nutrition (HPN; 27% CP, 10% fat, GE = 3.8 Mcal/days) in a 2 × 3 factorial design to test the impact of diet on neonatal calf growth, organ weight and skeletal muscle morphometry with time. Groups of calves (n = 4 or 5) were euthanised at 2, 4 and 8 week of age and organ and empty carcass weights were recorded. Body composition was measured by DXA. Longissimus muscle (LM) fibre cross-sectional area (CSA), fibre/mm² and Pax7 were measured by immunohistology. Satellite cells were isolated at each time point and proliferation rates were measured by EdU incorporation. Calves fed a HPN had greater (p < 0.05) BW, ADG and hip height than those fed a LPN for 2, 4 or 8 weeks. HPN calves contained a greater (p < 0.05) percentage of fat tissue than LPN calves. Liver, spleen and thymus weights were less (p < 0.05) in LPN calves than HPN animals. Calves fed HPN had larger (p < 0.05) LM CSA at 8 weeks than LPN fed animals with no differences between the groups in numbers of satellite cells per fibre. Proliferation rates of satellite cells isolated from HPN fed calves were greater (p < 0.05) at 2 weeks than LPN fed animals, which exhibited greater (p < 0.05) proliferation rates at 4 weeks than HPN fed calves. We conclude a LPN diet reduces body growth and organ size and metabolically reprograms satellite cell activity.

A Multicenter, Randomized, Observer-blinded, Active-controlled Study to Evaluate the Safety and Efficacy of Ceftaroline Versus Comparator in Pediatric Patients With Acute Bacterial Skin and Skin Structure Infection

BACKGROUND

Ceftaroline has in vitro activity against bacterial isolates, including methicillin-resistant Staphylococcus aureus. This is the first study to investigate ceftaroline fosamil in pediatric patients with acute bacterial skin and skin structure infections (ABSSSIs).

METHODS

A multicenter, observer-blinded study (NCT01400867) in pediatric patients (2 months-17 years of age) with ABSSSIs. Patients were randomized 2:1 to receive intravenous (IV) ceftaroline fosamil or IV comparator (vancomycin or cefazolin, plus optional aztreonam) with optional switch to oral antibacterials from Day 4. Safety and clinical outcomes were assessed.

RESULTS

Of 163 enrolled patients, 159 received treatment. Treatment groups were comparable for baseline characteristics. Rates of study drug-related treatment-emergent adverse events were similar for ceftaroline fosamil [22% (23/106)] and comparator [23% (12/53)]. One serious adverse event, considered to be related to IV study drug, occurred in the ceftaroline fosamil group (hypersensitivity). In both the treatment groups, 85% (ceftaroline fosamil, 91/107 and comparator, 44/52) of the modified intent-to-treat population achieved early clinical response (≥20% reduction in infection area from baseline). Clinical cure rates at test-of-cure were high [ceftaroline fosamil, 94% (101/107) and comparator, 87% (45/52)]. For patients evaluated 8 to 15 days after the last dose of any antibiotic (IV or oral), from whom methicillin-resistant Staphylococcus aureus was initially isolated, a favorable microbiologic response (reflecting the efficacy of oral/IV therapy and capturing a relapse or reinfection) was achieved with ceftaroline fosamil [89% (16/18)] and comparator [57% (4/7)].

CONCLUSIONS

Ceftaroline fosamil, with optional oral switch, was as well-tolerated and effective in pediatric patients with ABSSSIs as comparator therapy.

A Multicenter, Randomized, Observer-blinded, Active-controlled Study Evaluating the Safety and Effectiveness of Ceftaroline Compared With Ceftriaxone Plus Vancomycin in Pediatric Patients With Complicated Community-acquired Bacterial Pneumonia

BACKGROUND

The broad-spectrum cephalosporin ceftaroline, a metabolite of the prodrug ceftaroline fosamil, has shown in vitro activity against clinical isolates from pediatric patients.

METHODS

This multicenter, randomized, observer-blinded, active-controlled study (NCT01669980) assessed the safety and effectiveness of ceftaroline fosamil compared with ceftriaxone plus vancomycin in patients between 2 months and 17 years of age with complicated community-acquired bacterial pneumonia. Patients were randomized 3:1 (stratified by age cohort) to receive either ceftaroline fosamil or ceftriaxone plus vancomycin (comparator) as intravenous therapy for ≥3 days. Patients who met specific study criteria on or after Study Day 4 were permitted to switch to an oral study drug. Safety assessments were treatment-emergent adverse events, and the effectiveness of treatment was assessed by clinical and microbiologic outcomes.

RESULTS

The median duration of intravenous treatment was 9.0 (range, 3.0-19.0) days in the ceftaroline fosamil group (N=30) and 7.5 (5.0-13.0) days in the comparator group (N=10). At least one treatment-emergent adverse event was experienced by 12/30 patients (40%) in the ceftaroline fosamil group and 8/10 (80%) in the comparator group; most treatment-emergent adverse events in both groups were mild to moderate in intensity. Clinical response rates in the modified intent-to-treat population were 52% (15/29 patients) in the ceftaroline fosamil group and 67% in the comparator group (6/9); clinical stability at Study Day 4 was 21% (6/29) and 22% (2/9), respectively.

CONCLUSIONS

Ceftaroline fosamil was well tolerated and showed similar clinical response rates to ceftriaxone plus vancomycin in pediatric patients with complicated community-acquired bacterial pneumonia.

A Randomized, Prospective Study of Pediatric Patients With Community-acquired Pneumonia Treated With Ceftaroline Versus Ceftriaxone

BACKGROUND

Community-acquired bacterial pneumonia (CABP) remains a major infection among children, despite the use of pneumococcal vaccination. Ceftaroline fosamil is a broad-spectrum cephalosporin antibiotic with activity against many bacteria, including Streptococcus pneumoniae (both penicillin-nonsusceptible and multidrug-resistant strains) and Staphylococcus aureus (including methicillin-resistant S. aureus). This article describes the safety, tolerability, and effectiveness of ceftaroline fosamil in the treatment of pediatric patients hospitalized with CABP, from a randomized, active-controlled, observer-blinded clinical study (registration number NCT01530763).

METHODS

Pediatric patients were stratified into 4 age cohorts and randomized (3:1) to receive either intravenous ceftaroline fosamil or ceftriaxone, with optional oral switch for a total treatment duration of 5-14 days. Enrollment was planned for 160 patients. Data collected included demographics, infection characteristics and pathogens. Treatment-emergent adverse events, clinical outcomes, and microbiologic responses were assessed.

RESULTS

Ceftaroline fosamil was well tolerated. Similar percentages of patients in the ceftaroline fosamil (55/121; 45%) and ceftriaxone (18/39; 46%) groups reported treatment-emergent adverse events. Coombs seroconversion was observed in 17% of patients in the ceftaroline fosamil group; however, no evidence of hemolytic anemia or hemolysis was found. No deaths were reported during the study. Ceftaroline fosamil had similar effectiveness to ceftriaxone, with high clinical cure rates at test-of-cure in the modified intent-to-treat population (94/107; 88% and 32/36; 89%, respectively). Three documented S. aureus infections were successfully treated in the ceftaroline group, including one caused by methicillin-resistant S. aureus.

CONCLUSIONS

The results of this study suggest that ceftaroline fosamil may be an important treatment option for pediatric patients hospitalized with CABP.

Harmonisation in study design and outcomes in paediatric antibiotic clinical trials: a systematic review

There is no global consensus on the conduct of clinical trials in children and neonates with complicated clinical infection syndromes. No comprehensive regulatory guidance exists for the design of antibiotic clinical trials in neonates and children. We did a systematic review of antibiotic clinical trials in complicated clinical infection syndromes (including bloodstream infections and community-acquired pneumonia) in children and neonates (0-18 years) to assess whether standardised European Medicines Agency (EMA) and US Food and Drug Administration (FDA) guidance for adults was used in paediatrics, and whether paediatric clinical trials applied consistent definitions for eligibility and outcomes. We searched MEDLINE, Cochrane CENTRAL databases, and ClinicalTrials.gov between Jan 1, 2000, and Nov 18, 2015. 82 individual studies met our inclusion criteria. The published studies reported on an average of 66% of CONSORT items. Study design, inclusion and exclusion criteria, and endpoints varied substantially across included studies. The comparison between paediatric clinical trials and adult EMA and FDA guidance highlighted that regulatory definitions are only variably applicable and used at present. Absence of consensus for paediatric antibiotic clinical trials is a major barrier to harmonisation in research and translation into clinical practice. To improve comparison of therapies and strategies, international collaboration among all relevant stakeholders leading to harmonised case definitions and outcome measures is needed.

Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Pneumococcal Meningitis in US Children

BACKGROUND

The impact of 13-valent pneumococcal conjugate vaccine (PCV13) on pneumococcal meningitis (PM) in US children is unknown. We compared the serotype distribution, antibiotic susceptibility, hospital course, and outcomes of children with PM 3 years before and 3 years after the introduction of PCV13.

METHODS

We identified patients ≤ 18 years of age with PM at 8 children's hospitals in the United States. Pneumococcal isolates were collected prospectively. Serotyping and antibiotic susceptibility were performed in a central laboratory. Clinical data were abstracted from medical records. Patients were divided into 3 subgroups: pre-PCV13 (2007-2009), transitional year (2010), and post-PCV13 (2011-2013). Categorical variables were analyzed by the χ(2) test and continuous variables by the Mann--Whitney U test.

RESULTS

During the study period, 173 of 1207 episodes (14%) of invasive pneumococcal disease were identified as PM; 76 of 645 (12%) were during 2007-2009 and 69 of 394 (18%) during 2011-2013 (50% increase; P = .03). The proportion of PCV13 serotype cases decreased from 54% in 2007-2009 to 27% in 2011-2013 (P = .001). Non-PCV13 serotype cases represented 73% of the isolates in 2011-2013. Isolates with ceftriaxone minimum inhibitory concentration ≥ 1 µg/mL decreased (13% to 3%) from 2007-2009 to 2011-2013 (P = .03). No significant differences were identified for hospital course or outcome, with the exception that a greater proportion of patients had subdural empyema and hemiparesis in 2011-2013.

CONCLUSIONS

After the introduction of PCV13, the number of cases of PM in children remained unchanged compared with 2007-2009, although the proportion of PCV13 serotypes decreased significantly. Serotype 19A continued to be the most common serotype in 2011-2013. Antibiotic resistance decreased significantly. Morbidity and case-fatality rate due to PM remain substantial.

Multicenter surveillance of Streptococcus pneumoniae isolates from middle ear and mastoid cultures in the 13-valent pneumococcal conjugate vaccine era

BACKGROUND

Streptococcus pneumoniae is a common cause of otitis media (OM) in children; mastoiditis remains an important complication of OM. Limited data are available on the impact of the 13-valent pneumococcal conjugate vaccine (PCV13) on pneumococcal otitis.

METHODS

Investigators from 8 children's hospitals in the United States prospectively collected pneumococcal isolates from middle ear or mastoid cultures from children from 2011 to 2013. Serotype and antibiotic susceptibilities were determined and PCV13 doses for children documented.

RESULTS

Over the 3-year period, the proportion of isolates included in PCV13 (plus a related serotype) decreased significantly (P = .0006) among the middle ear/mastoid isolates (2011, 50% [74/149]; 2012, 40.5% [47/116]; 2013, 29% [34/118]). The number of serotype 19A isolates in 2013 (n = 12, 10.2% of total) decreased 76% compared with the number of 19A isolates in 2011 (n = 50, 33.6% of total). Of the children from whom serotype 19A was isolated (n = 93), 55% had previously received <3 doses of PCV13. The most common non-PCV13 serotypes for the combined years were 35B (n = 37), 21 (n = 20), 23B (n = 20), 15B (n = 18), 11 (n = 17), 23A (n = 14), 15A (n = 14), and 15C (n = 14). The proportion of isolates with a penicillin minimal inhibitory concentration >2 µg/mL decreased significantly over the 3 years (2011, 22% [35/154]; 2012, 20% [24/118]; 2013, 10% [12/120]; P < .02).

CONCLUSIONS

The number of pneumococcal isolates and the percentage of isolates with high-level penicillin resistance from cultures taken from children with OM or mastoiditis for clinical indications have decreased following PCV13 use, largely related to decreases in serotype 19A isolates.

Experimental investigation of chair type, row spacing, occupants, and carpet on theatre chair absorption

This paper examines how the individual variations of chair type, row spacing, as well as the presence of occupants and carpet, combine to influence the absorption characteristics of theater chairs as a function of sample perimeter-to-area (P/A) ratios. Scale models were used to measure the interactive effects of the four test variables on the chair absorption characteristics, avoiding the practical difficulties of full scale measurements. All of the test variables led to effects that could lead to important changes to auditorium acoustics conditions. At mid and higher frequencies, the various effects can usually be explained as due to, more or less, porous absorbing material. In the 125 and 250 Hz octave bands, the major changes were attributed to resonant absorbing mechanisms. The results indicate that for accurate predictions of the effective absorption of the chairs in an auditorium, one should use the P/A method and reverberation chamber tests of the chair absorption coefficients to predict the absorption coefficients of each block of chairs and use these results as input in a room acoustics computer model of the auditorium. The application of these results to auditorium acoustics design is described, more approximate approaches are considered, and relations to existing methods are discussed.

Centers for disease control and prevention expert panel meetings on prevention and treatment of anthrax in adults

The Centers for Disease Control and Prevention convened panels of anthrax experts to review and update guidelines for anthrax postexposure prophylaxis and treatment. The panels included civilian and military anthrax experts and clinicians with experience treating anthrax patients. Specialties represented included internal medicine, pediatrics, obstetrics, infectious disease, emergency medicine, critical care, pulmonology, hematology, and nephrology. Panelists discussed recent patients with systemic anthrax; reviews of published, unpublished, and proprietary data regarding antimicrobial drugs and anthrax antitoxins; and critical care measures of potential benefit to patients with anthrax. This article updates antimicrobial postexposure prophylaxis and antimicrobial and antitoxin treatment options and describes potentially beneficial critical care measures for persons with anthrax, including clinical procedures for infected nonpregnant adults. Changes from previous guidelines include an expanded discussion of critical care and clinical procedures and additional antimicrobial choices, including preferred antimicrobial drug treatment for possible anthrax meningitis.

Vancomycin monitoring in children using bayesian estimation

BACKGROUND

Optimal monitoring of vancomycin in children needs evaluation using the exposure target with area under the curve (AUC) of the serum concentrations versus time over 24 hours. Our study objectives were to: (1) compare the accuracy and precision of vancomycin AUC estimations using 2 sampling strategies-1 serum concentration sample (1S, near trough) versus 2 samples (2S, near peak and trough) against the rich sample (RS) method; and (2) determine the performance of these strategies in predicting future AUC against an internal validation sample (VS).

METHODS

This was a retrospective cohort study using population-based pharmacokinetic modeling with Bayesian post hoc individual estimations in nonlinear mixed effects modeling (version 7.2). Pediatric subjects 3 months-21 years of age who received vancomycin ≥48 hours and had more than 3 drug samples within the first ≤96 hours of therapy were enrolled. Outcome measures were the accuracy, precision, and internal predictive performance of AUC estimations using 2 monitoring strategies (ie, 1S versus 2S) against the RS (which was derived from modeling all serum vancomycin concentrations obtained anytime during therapy) and VS (from serum concentrations obtained after 96 hours of therapy).

RESULTS

Analysis included 138 subjects with 712 vancomycin serum concentrations. Median age was 6.1 (interquartile range, 2.2-12.2) years, weight 22 (13-38) kg, and baseline serum creatinine 0.37 (0.30-0.50) mg/dL. Both accuracy and precision were improved with the 2S, compared with 1S, for AUC estimations (-2.0% versus -7.6% and 10.3% versus 12.8%, respectively) against the RS. Improved accuracy and precision were also observed for 2S when evaluated against VS in predicting future AUC.

CONCLUSIONS

Compared with 1S, the 2S sampling strategy for vancomycin monitoring improved accuracy and precision in estimating and predicting future AUC. Evaluating 2 drug concentrations in children may be prudent to ensure adequate drug exposure.

Assessment of musculoskeletal toxicity 5 years after therapy with levofloxacin

BACKGROUND

Safety concerns for fluoroquinolones exist from animal studies demonstrating cartilage injury in weight-bearing joints, dependent on dose and duration of therapy. For children treated with levofloxacin or comparator in randomized, prospective, comparative studies for acute otitis media and community-acquired pneumonia, this 5-year follow-up safety study was designed to assess the presence/absence of cartilage injury.

METHODS

Children enrolled in treatment studies were also enrolled in a 1-year follow-up safety study, which; focused on musculoskeletal adverse events (MSAE). Those with persisting MSAEs, protocol-defined musculoskeletal disorders, or of concern to the Data Safety and Monitoring Committee were requested to enroll in four additional years of follow-up, the subject of this report.

RESULTS

Of the 2233 subjects participating in the 12-month follow-up study, 124 of 1340 (9%) of the levofloxacin subjects, and 83 of 893 (9%) of the comparator subjects were continued for 5-year posttreatment assessment. From children identified with an MSAE during years 2 through 5 posttreatment, the number that were "possibly related" to drug therapy was equal for both arms: 1 of 1340 for levofloxacin and 1 of 893 for comparator. Of all cases of MSAE assessed by the Data Safety and Monitoring Committee at 5 years' posttreatment, no case was assessed as "likely related" to study drug.

CONCLUSIONS

With no clinically detectable difference between levofloxacin- and comparator-treated children in MSAEs presenting between 1 and 5 years in these safety studies, risks of cartilage injury with levofloxacin appear to be uncommon, are clinically undetectable during 5 years, or are reversible.

Pediatric anthrax clinical management

Anthrax is a zoonotic disease caused by Bacillus anthracis, which has multiple routes of infection in humans, manifesting in different initial presentations of disease. Because B anthracis has the potential to be used as a biological weapon and can rapidly progress to systemic anthrax with high mortality in those who are exposed and untreated, clinical guidance that can be quickly implemented must be in place before any intentional release of the agent. This document provides clinical guidance for the prophylaxis and treatment of neonates, infants, children, adolescents, and young adults up to the age of 21 (referred to as "children") in the event of a deliberate B anthracis release and offers guidance in areas where the unique characteristics of children dictate a different clinical recommendation from adults.