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Background: To determine if receiving targeted antimicrobial (AM) prophylaxis has an effect on the rate of postoperative infections in patient's colonized with a multidrug resistant organism (MDRO) undergoing cardiothoracic surgery (CTS)., Methods: Single-center, retrospective medical record review of pediatric patients from birth to 18 years of age undergoing CTS from January 2013 to September 2018. Demographic data collected included age, specific MDRO, site of MDRO colonization, type of surgery, perioperative AM agent and type of infection. Patients were stratified into 2 groups, MDRO+ and MDRO-. Demographic and clinical characteristics were compared between groups with a Student's t test for continuous variables and a χ2, Fisher exact test or Mann-Whitney U test for noncontinuous variables. A 2-sided significance level of α = 0.05 was used to determine statistical significance. All analyses were performed using IBM SPSS Version 24 (SPSS Inc., Chicago, IL)., Results: Fifty patients (26 males/24 females) were included in the MDRO (+) group and 295 patients (168 males/127 females) in the MDRO (-) group. The median age was 0.48 years (interquartile range 0.24-1 year) and 0.9 years (interquartile range 0.19-8 years) in the MDRO (+) and MDRO (-) groups, P = 0.003. 2 of 50 (4%) MDRO (+) patients and 15 of 295 (5.1 %) MDRO (-) patients developed an infection, P = 1. 10 of 50 (20%) MDRO (+) patients received targeted AM toward the MDRO and none developed an infection. Of the 2 MDRO (+) patients with infection, 1 was infected with the MDRO. For MDRO (+) patients, there was no difference in the rate of infection whether targeted AM therapy was received, P = 1., Conclusions: There was no difference in the rate of postoperative infection between MDRO (+) and MDRO (-) patients. Additionally, these preliminary pediatric data suggest targeting AM agents to a specific MDRO does not impact the rate of postoperative infection in children undergoing CTS. Larger studies are warranted to confirm these findings.

Objectives: To determine the oxygenator impact on alterations of ceftolozane/tazobactam in a contemporary neonatal/pediatric (1/4-inch) and adolescent/adult (3/8-inch) extracorporeal membrane oxygenation circuit including the Quadrox-i oxygenator (Maquet, Wayne, NJ)., Design: A 1/4-inch and 3/8-inch, simulated closed-loop extracorporeal membrane oxygenation circuits were prepared with a Quadrox-i pediatric and Quadrox-i adult oxygenator and blood primed. Additionally, 1/4-inch and 3/8-inch circuits were also prepared without an oxygenator in series. A one-time dose of ceftolozane/tazobactam was administered into the circuits and serial preoxygenator and postoxygenator concentrations were obtained at 5 minutes, 1, 2, 3, 4, 5, 6, and 24-hour time points. Ceftolozane/tazobactam was also maintained in a glass vial and samples were taken from the vial at the same time periods for control purposes to assess for spontaneous drug degradation SETTING:: A free-standing extracorporeal membrane oxygenation circuit., Patients: None., Interventions: Single-dose administration of ceftolozane/tazobactam into closed-loop extracorporeal membrane oxygenation circuits prepared with and without an oxygenator in series with serial preoxygenator, postoxygenator, and reference samples obtained for concentration determination over a 24-hour study period., Measurements and Main Results: For the 1/4-inch circuit, there was approximately 92% ceftolozane and 22-25% tazobactam loss with the oxygenator in series and 19-30% ceftolozane and 31-34% tazobactam loss without an oxygenator in series at 24 hours. For the 3/8-inch circuit, there was approximately 85% ceftolozane and 29% tazobactam loss with the oxygenator in series and 25-27% ceftolozane and 23-26% tazobactam loss without an oxygenator in series at 24 hours. The reference ceftolozane and tazobactam concentrations remained relatively constant during the entire study period demonstrating the drug loss in each size of the extracorporeal membrane oxygenation circuit with or without an oxygenator was not a result of spontaneous drug degradation., Conclusions: This ex vivo investigation demonstrated substantial ceftolozane loss within an extracorporeal membrane oxygenation circuit with an oxygenator in series with both sizes of the Quadrox-i oxygenator at 24 hours and significant ceftolozane loss in the absence of an oxygenator. Tazobactam loss was similar regardless of the presence of an oxygenator. Further evaluations with multiple dose in vitro and in vivo investigations are needed before specific drug dosing recommendations can be made for clinical application with extracorporeal membrane oxygenation.

Objectives: Our aim was to describe the pharmacokinetics of cefazolin in paediatric patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) who received cefazolin for peri-operative surgical prophylaxis in addition to having cefazolin added to the CPB circuit priming solution. Secondary aims were to determine the pharmacodynamic exposure associated with the addition of cefazolin to the CPB priming solution and to assess whether a target cefazolin concentration range for the CPB priming solution could be identified., Methods: A multicentre, prospective, open-label pharmacokinetic study was carried out in children from birth to 16 years of age undergoing cardiac surgery., Results: Forty-one patients met the inclusion criteria and accounted for 492 samples for analysis. Cefazolin concentrations were best described by a one-compartment model with weight as a covariate on the volume of distribution (Vd) with allometric scaling. The mean ± standard deviation (SD) total body CL for the birth-6 month cohort was 0.009 ± 0.006 mL/min/kg with a mean ± SD Vd of 0.59 ± 0.26 L/kg, the mean ± SD total body CL for the 7 month-3 year cohort was 0.01 ± 0.005 mL/min/kg with a mean ± SD Vd of 0.79 ± 0.15 L/kg, and the mean ± SD total body CL for the 4-16 year cohort was 0.007 ± 0.004 mL/min/kg with a mean ± SD Vd of 3.4 ± 0.94 L/kg. The median cefazolin loss in the CPB circuit ranged from 78% to 95% and the median patient cefazolin concentration after CPB circuit detachment ranged from 92 to 197 mg/L., Conclusions: These data demonstrate that mixing cefazolin in the CPB circuit priming solution was effective in maintaining cefazolin serum concentrations during surgery. If this practice is utilized, re-dosing of cefazolin during the CPB run and upon CPB circuit detachment is most probably not needed. Larger pharmacokinetic studies are warranted., (© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objectives: To determine the oxygenator impact on alterations of ceftaroline in a contemporary neonatal/pediatric (1/4-inch) and adolescent/adult (3/8-inch) extracorporeal membrane oxygenation circuit including the Quadrox-i oxygenator (Maquet, Wayne, NJ)., Design: Quarter-inch and 3/8-inch, simulated closed-loop extracorporeal membrane oxygenation circuits were prepared with a Quadrox-i pediatric and Quadrox-i adult oxygenator and blood primed. Additionally, 1/4-inch and 3/8-inch circuits were also prepared without an oxygenator in series. An one-time dose of ceftaroline was administered into the circuits, and serial pre- and postoxygenator concentrations were obtained at 5 minutes, 1-, 2-, 3-, 4-, 5-, 6-, and 24-hour time points. Ceftaroline was also maintained in a glass vial, and samples were taken from the vial at the same time periods for control purposes to assess for spontaneous drug degradation., Setting: A free-standing extracorporeal membrane oxygenation circuit., Patients: None., Intervention: Single dose administration of ceftaroline into closed-loop extracorporeal membrane oxygenation circuits prepared with and without an oxygenator in series with serial preoxygenator, postoxygenator, and reference samples obtained for concentration determination over a 24-hour study period., Measurements and Main Results: For the 1/4-inch circuit with an oxygenator, there was 79.8% drug loss preoxygenator and 82.5% drug loss postoxygenator at 24 hours. There was a statistically significant difference (p < 0.01) in the amount of ceftaroline remaining at 24 hours when compared with each prior time point for the 1/4-inch circuit. For the 1/4-inch circuit without an oxygenator, there was no significant drug loss at any study time point. For the 3/8-inch circuit with an oxygenator, there was 76.2% drug loss preoxygenator and 77.6% drug loss postoxygenator at 24 hours. There was a statistically significant difference (p < 0.01) in the amount of ceftaroline remaining at 24 hours when compared with each prior time point for the 3/8-inch circuit. For the 3/8-inch circuit without an oxygenator, there was no significant drug loss at any study time point. The reference ceftaroline concentrations remained relatively constant during the entire study period demonstrating the ceftaroline loss in each size of the extracorporeal membrane oxygenation circuit with or without an oxygenator was not a result of spontaneous drug degradation and primarily the result of the oxygenator., Conclusions: This ex vivo investigation demonstrated significant ceftaroline loss within an extracorporeal membrane oxygenation circuit with an oxygenator in series with both sizes of the Quadrox-i oxygenator at 24 hours. Therapeutic concentrations of ceftaroline in the setting of extracorporeal membrane oxygenation may not be achieved with current U.S. Food and Drug Administration-recommended doses, and further evaluation is needed before specific drug dosing recommendations can be made for clinical application with extracorporeal membrane oxygenation.

Objectives: To describe the ceftaroline pharmacokinetics in critically ill children treated for suspected or confirmed methicillin-resistant Staphylococcus aureus infections, including blood stream infection and describe the microbiological and clinical outcomes., Design: Retrospective electronic medical record review., Settings: Free-standing tertiary/quaternary pediatric children's hospital., Patients: Critically ill children receiving ceftaroline monotherapy or combination therapy for suspected or confirmed methicillin-resistant S. aureus infections in the PICU., Intervention: None., Measurements and Main Results: Seven patients, three females (43%), and four males (57%), accounted for 33 ceftaroline samples for therapeutic drug management. A median of four samples for therapeutic drug management was collected per patient (range, 2-9 samples). The median age was 7 years (range, 1-13 yr) with a median weight of 25.5 kg (range, 12.6-40.1 kg). Six of seven patients (86%) demonstrated an increase in volume of distribution, five of seven patients (71%) demonstrated an increase in clearance, and 100% of patients demonstrated a shorter half-life estimate as compared with the package insert estimate. Six of seven patients (85.7%) had documented methicillin-resistant S. aureus growth from a normally sterile site with five of six (83.3%) having documented BSI, allowing six total patients to be evaluated for the secondary objective of microbiological and clinical response. All six patients achieved a positive microbiological and clinical response for a response rate of 100%., Conclusions: These data suggest the pharmacokinetics of ceftaroline in PICU patients is different than healthy pediatric and adult patients, most notably a faster clearance and larger volume of distribution. A higher mg/kg dose and a more frequent dosing interval for ceftaroline may be needed in PICU patients to provide appropriate pharmacodynamic exposures. Larger pharmacokinetic, pharmacodynamic, and interventional treatment trials in the PICU population are warranted.

Objectives: To determine whether contemporary β-lactam anti-infective dosing recommendations in critically ill children achieve concentrations associated with maximal anti-infective activity. The secondary objective was to describe the microbiological and clinical outcomes associated with β-lactam therapeutic drug management., Design: Electronic Medical Record Review., Setting: A 189-bed, freestanding children's tertiary care teaching hospital in Philadelphia, PA., Patients: Patients admitted to the PICU from September 1, 2014, to May 31, 2017, with sepsis and those receiving extracorporal therapy with either extracorporeal membrane oxygenation or continuous renal replacement therapy that had routine β-lactam therapeutic drug management., Interventions: None., Measurements and Main Results: Eighty-two patients were in the total cohort and 23 patients in the infected cohort accounting for 248 samples for therapeutic drug management analysis. The median age was 1 year (range, 4 d to 18 yr) with a mean weight of 19.7 ± 22.3 kg (range, 2.7-116 kg). Twenty-three patients (28%) had growth of an identified pathogen from a normally sterile site. Seventy-eight of 82 patients (95%) had subtherapeutic anti-infective concentrations and did not attain the primary pharmacodynamic endpoint. All patients in the infected cohort achieved a microbiological response, and 22 of 23 (95.7%) had a positive clinical response., Conclusions: Overall, 95% of patients had subtherapeutic anti-infective concentrations and did not achieve the requisite pharmacodynamic exposure with current pediatric dosing recommendations. All patients achieved a microbiological response, and 95.7% achieved clinical response with active β-lactam therapeutic drug management. These data suggest β-lactam therapeutic drug management is a potentially valuable intervention to optimize anti-infective pharmacokinetics and the pharmacodynamic exposure. Further, these data also suggest the need for additional research in specific pediatric populations and assessing clinical outcomes associated with β-lactam therapeutic drug management in a larger cohort of pediatric patients.

Objectives: To evaluate the population pharmacokinetics and pharmacodynamic target attainment of vancomycin in neonates with a contemporary ¼-inch extracorporeal life support circuit with a Quadrox-iD Pediatric oxygenator (Maquet Cardiovascular, LLC, Wayne, NJ)., Design: Retrospective medical record review., Setting: Two free-standing tertiary/quaternary pediatric children's hospitals., Patients: Neonates receiving either veno-arterial or veno-venous extracorporeal life support and vancomycin for empiric or definitive therapy with resulting serum concentrations., Interventions: None., Measurements and Main Results: Twelve patients with a median gestations age of 39 weeks (range 36-41 wk) and a median postnatal age of 9.5 days (range 0-28 d) accounted for 14 courses of vancomycin therapy while on extracorporeal life support and were included in the analysis. The median weight was 3.1 kg (range 2.2-4.41 kg) with five of 12 patients (41.7%) being female. Vancomycin concentrations were best described by an one-compartment model incorporating allometric scaling of estimated glomerular filtration rate on clearance. The mean total body clearance (mL/min/kg) for the population was 3.48 ± 1.31 mL/min/kg, and the mean total volume of distribution (L/kg) for the population was 1.2 ± 0.4 L/kg. The intermittent and continuous infusion dosing regimens that provided for the highest percentage of trough concentrations in the range of 10-20 mg/L were the 10 mg/kg/dose IV q8h, 12.5 mg/kg/dose IV q8-12h, 15 mg/kg/dose IV q12h, and 20 mg/kg/dose IV q12h, and the 20, 25, and 30 mg/kg/d continuous infusion regimens, respectively. All regimens allowed for an area under the concentration:minimum inhibitory concentration ratio of 400:1 for minimum inhibitory concentrations of less than or equal to 0.5 mg/L for a 90% PTA. None of the simulated regimens had a greater than 90% probability of achieving an area under the concentration:minimum inhibitory concentration ratio of 400:1 for vancomycin minimum inhibitory concentrations greater than or equal to 1 mg/L while maintaining trough concentrations in the range of 10-20 mg/L., Conclusions: To our knowledge, this is the first pharmacokinetic and pharmacodynamic study of neonates receiving vancomycin with a contemporary ¼-inch extracorporeal life support circuit including the Quadrox-iD Pediatric oxygenator (Maquet Cardiovascular, LLC). The data suggest differences in vancomycin pharmacokinetics compared with previous extracorporeal life support data, notably a more rapid clearance, which could result in lower vancomycin concentrations. Considering this, a more aggressive initial dosing regimen may need to be employed in infants on extracorporeal life support.

Objectives: To describe our experience with achieving therapeutic serum vancomycin concentrations in pediatric continuous renal replacement therapy by using continuous infusion vancomycin by mixing vancomycin into the continuous renal replacement therapy solution., Design: Retrospective chart review., Setting: A 189-bed, freestanding children's tertiary care teaching hospital in Philadelphia, PA., Patients: Pediatric patients receiving continuous renal replacement therapy from April 1, 2009, through December 31, 2014., Interventions: None., Measurements and Main Results: There were a total of 21 patients who received continuous renal replacement therapy during the study period. Of these, 11 (52.3%) received vancomycin in the continuous renal replacement therapy solution. The median (range) concentration of vancomycin added to the continuous renal replacement therapy solution was 25 mg/L (18-35 mg/L). The mean vancomycin plateau level was 22.8 ± 3.3 mg/L. All patients achieved a serum vancomycin plateau level that was greater than 15 mg/L. There were no adverse events related to the addition of vancomycin to the continuous renal replacement therapy solution., Conclusions: The addition of vancomycin to the continuous renal replacement therapy solution(s) is an effective modality that is used for delivering vancomycin continuous infusion and for ensuring therapeutic vancomycin serum plateau levels in the setting of pediatric continuous renal replacement therapy. Further studies are required to evaluate whether this delivery method can lead to improved patient outcomes.

Neither guidelines nor best practices for the treatment of external ventricular drain (EVD) and ventriculoperitoneal shunt infections exist. An antimicrobial regimen with a broad spectrum of activity and adequate cerebrospinal fluid (CSF) penetration is vital in the management of both EVD and ventriculoperitoneal infections. In this case report, we describe the pharmacokinetics of continuous-infusion meropenem for a 2-year-old girl with Serratia marcescens ventriculitis. A right frontal EVD was placed for the management of a posterior fossa mass with hydrocephalus and intraventricular hemorrhage. On hospital day 6, CSF specimens were cultured, which identified a pan-sensitive Serratia marcescens with an initial cefotaxime minimum inhibitory concentration of 1 μg/ml or less. The patient was treated with cefotaxime monotherapy from hospital days 6 to 17, during which her CSF cultures and Gram's stain remained positive. On hospital day 26, Serratia marcescens was noted to be resistant to cefotaxime (minimum inhibitory concentration > 16 μg/ml), and the antimicrobial regimen was ultimately changed to meropenem and amikacin. Meropenem was dosed at 40 mg/kg/dose intravenously every 6 hours, infused over 30 minutes, during which, simultaneous serum and CSF meropenem levels were measured. Meropenem serum and CSF levels were measured at 2 and 4 hours from the end of the infusion with the intent to perform a pharmacokinetic/pharmacodynamic analysis. The resulting serum meropenem levels were 12 μg/ml at 2 hours and "undetectable" at 4 hours, with CSF levels of 1 and 0.5 μg/ml at 2 and 4 hours, respectively. On hospital day 27, the meropenem regimen was changed to a continuous infusion of 200 mg/kg/day, with repeat serum and CSF meropenem levels measured on hospital day 33. The serum and CSF levels were noted to be 13 and 0.5 μg/ml, respectively. The serum level of 13 μg/ml corresponds to an estimated meropenem clearance from the serum of 10.2 ml/kg/minute. Repeat meropenem levels from the serum and CSF on hospital day 37 were 15 and 0.5 μg/ml, respectively. After instituting the continuous-infusion meropenem regimen, only three positive CSF Gram's stains were noted, with the CSF cultures remaining negative. The continuous-infusion dosing regimen allowed for 100% probability of target attainment in the serum and CSF and a successful clinical outcome., (© 2015 Pharmacotherapy Publications, Inc.)

Meropenem, a broad-spectrum carbapenem, is commonly used for empirical and definitive therapy in the pediatric intensive care unit (ICU). Pharmacokinetic data to guide dosing in children, however, are limited to healthy volunteers or patients who are not in the ICU. Adult data demonstrate that pharmacokinetic parameters such as the volume of distribution and clearance can be significantly altered in individuals receiving extracorporeal membrane oxygenation (ECMO). Alterations in the volume of distribution and clearance of antimicrobials in patients with sepsis and septic shock have also been documented, and these patients have demonstrated lower than expected antimicrobial serum concentrations based on standard dosing regimens. Therefore, an understanding of the pharmacokinetic changes in critically ill children receiving ECMO is crucial to determining the most appropriate dose and dosing interval selection for any antimicrobial therapy. In this case report, we describe the pharmacokinetics of a continuous infusion of meropenem in a pediatric cardiac ICU patient who was receiving concurrent extracorporeal life support. The patient was an 8-month-old male infant who underwent a Glenn procedure and pulmonary artery reconstruction. Postoperatively, he required ECMO with a total run of 21 days. On day 11 of ECMO, a bronchoalveolar lavage was performed, and blood cultures from days 11 and 12 of ECMO grew Pseudomonas aeruginosa, with a meropenem minimum inhibitory concentration (MIC) of 0.5 μg/ml. On ECMO day 13, meropenem was initiated with a loading dose of 40 mg/kg and infused over 30 minutes, followed by a continuous infusion of 200 mg/kg/day. A meropenem serum concentration measured 8 hours after the start of the infusion was 46 μg/ml. Repeat levels were measured on days 3 and 9 of meropenem therapy and were 39 and 42 μg/ml, respectively. Repeat blood and respiratory cultures remained negative. This meropenem regimen (40-mg/kg bolus followed by a continuous infusion of 200 mg/kg/day) was successful in providing a target attainment of 100% for serum and lung concentrations above the MIC for at least 40% of the dosing interval and was associated with a successful clinical outcome., (© 2014 Pharmacotherapy Publications, Inc.)