Healthcare-associated Staphylococcus aureus Bacteremia in Children: Evidence for Reverse Vancomycin Creep and Impact of Vancomycin Trough Values on Outcome

Vancomycin AUC0-24 estimation using first-order pharmacokinetic methods in pediatric patients

INTRODUCTION

The optimal dosing and monitoring of vancomycin in pediatrics is still unknown but has evolved to emphasize area under the curve over 24 h (AUC0-24) over minimum concentration (Cmin) monitoring. Real-world data supporting the feasibility of two-concentration kinetics with first-order equations for the estimation of vancomycin AUC0-24 in pediatric patients are lacking.

OBJECTIVES

To describe the interplay of vancomycin dose, AUC0-24, and Cmin using first-order equations within four pediatric age groups.

METHODS

This is a single-center, retrospective cohort study analyzing pediatric patients (<18 years) receiving intravenous vancomycin between 2020 and 2022. Included patients received at least 24 h of intravenous vancomycin with two concentrations obtained within 96 h of therapy initiation. Patients with baseline renal dysfunction were excluded. Patients were divided into four age categories: neonates (≤28 days), infants (29 days to <1 year), children (1-12 years), and adolescents (13-17 years). First-order equations were utilized to estimate pharmacokinetic parameters and AUC0-24.

RESULTS

Overall, 219 patients (median age of 6 years [IQR 1-12]) met inclusion criteria. The median vancomycin daily dose was 30 mg/kg in neonates, 70 mg/kg in infants and children, and 52 mg/kg in adolescents. Median Cmin and AUC0-24 values among all age groups were 8.68 mg/L and 505 mg * h/L, respectively. For AUC0-24 values outside of the therapeutic range (400-600 mg * h/L), more values were SUPRAtherapeutic (>600 mg * h/L) than SUBtherapeutic (<400 mg * h/L). The overall trend within our data showed suboptimal correlation between Cmin and AUC0-24. However, 71% of patients with Cmin values of 5-10 mg/L had an AUC0-24 within the therapeutic range of 400-600 mg * h/L, whereas 23 patients (92%) with a SUPRAtherapeutic AUC0-24 had a Cmin value ≥15 mg/L. Approximately 10% of patients experienced acute kidney injury.

CONCLUSIONS

Our data describe the relationship between vancomycin dose, Cmin, and AUC0-24 in pediatric patients. We demonstrated the feasibility of using first-order equations to estimate AUC0-24, using two concentrations obtained at steady state to monitor efficacy and safety in pediatric patients receiving intravenous vancomycin. Our data showed suboptimal correlation between AUC0-24 and Cmin, which indicates that Cmin should not be used as a surrogate marker for a therapeutic AUC0-24 in pediatric patients. In alignment with the 2020 vancomycin consensus guidelines, we suggest utilizing AUC0-24 for efficacy and safety monitoring.

Necrotizing Pneumonia in Children: Early Recognition and Management

Necrotizing pneumonia (NP) is an uncommon complicated pneumonia with an increasing incidence. Early recognition and timely management can bring excellent outcomes. The diagnosis of NP depends on chest computed tomography, which has radiation damage and may miss the optimal treatment time. The present review aimed to elaborate on the reported predictors for NP. The possible pathogenesis of Streptococcus pneumoniae, Staphylococcus aureus, Mycoplasma pneumoniae and coinfection, clinical manifestations and management were also discussed. Although there is still a long way for these predictors to be used in clinical, it is necessary to investigate early predictors for NP in children.

Vancomycin-associated acute kidney injury epidemiology in children: a systematic review

INTRODUCTION

Vancomycin is a recognised cause of drug-induced acute kidney injury (AKI).

OBJECTIVE

The aim of this systematic review was to summarise the incidence of, and the risk factors for, vancomycin-associated AKI (v-AKI) in children.

DESIGN

A systematic search was performed in November 2020 on the search engines PubMed, Web of Science and Medline, using predefined search terms. The inclusion criteria were primary paediatric studies, intervention with vancomycin and studies that included AKI as an outcome. Study quality was assessed using the relevant Critical Appraisal Skills Programme checklist. The data are reported using descriptive statistics.

RESULTS

890 studies were identified and screened with 25 studies suitable for inclusion. A cohort of 12 730 patients with v-AKI were included and the incidence of v-AKI in children was found to be 11.8% (1.6%-27.2%). The median age of the cohort was 2.5 years (range 0-23) and 57% were male patients. Risk factors that increased the likelihood of v-AKI were concomitant use of nephrotoxic medications, increased trough concentrations and, to a lesser extent, increased dose, longer duration of treatment, impaired renal function and if the patient required paediatric intensive care.

CONCLUSIONS

The incidence of v-AKI in children is significant and methods to reduce this risk should be considered. Further prospective interventional studies to understand the mechanisms of nephrotoxicity from vancomycin are needed and targeting risk factors may make vancomycin administration safer.

Relationship between Vancomycin Trough Serum Concentrations and Clinical Outcomes in Children: a Systematic Review and Meta-Analysis

To systematically evaluate the relationships between vancomycin trough serum concentrations and clinical outcomes in children using meta-analysis. Several databases, including PubMed, Elsevier, Web of Science, EMBASE, Medline, clinicaltrials.gov, the Cochrane Library, and three Chinese databases (Wanfang Data, China National Knowledge Infrastructure, and SINOMED), were comprehensively searched to obtain research articles on vancomycin use in children from inception through December 2021. All studies were screened and evaluated using the Cochrane systematic review method. Then, the feature information was extracted for meta-analysis. The evaluated results included clinical efficacy, vancomycin-associated nephrotoxicity, hepatotoxicity, ototoxicity, mortality, and microbial clearance. A total of 35 studies involving 4820 children were included in the analysis. The meta-analysis showed that compared with children with vancomycin trough concentrations <10 μg/mL, those with vancomycin trough concentrations ≥10 μg/mL had a higher clinical efficacy rate [OR: 2.23, 95% CI: 1.29 to 3.84, P = 0.004] and higher incidences of nephrotoxicity [OR: 2.76, 95% CI: 1.51 to 5.07, P = 0.001], ototoxicity [OR: 1.87, 95% CI: 1.08 to 3.23, P = 0.02] and microbial clearance [OR: 2.36, 95% CI: 1.53 to 3.64, P = 0.0001]. All-cause mortality [OR: 1.07, 95% CI: 0.45 to 2.53, P = 0.88] and hepatotoxicity [OR: 0.84, 95% CI: 0.46 to 1.53, P = 0.57] were similar between the two groups. Subgroup analysis showed that compared with children with vancomycin trough concentrations of 10 to 15 μg/mL, those with vancomycin trough concentrations >15 μg/mL had a higher incidence of nephrotoxicity [OR: 2.64, 95% CI: 1.28 to 5.43, P = 0.008], but there was no significant difference in clinical efficacy [OR: 0.85, 95% CI: 0.30 to 2.44, P = 0.76]. A vancomycin trough concentration of 10 to 15 μg/mL can improve clinical efficacy in children. Additionally, avoidance of trough concentrations >15 μg/mL can reduce the incidence of adverse reactions.

Falsely Undetectable Vancomycin Levels in a Pediatric Patient With Chronic Granulomatous Disease

A child with chronic granulomatous disease on vancomycin treatment had V trough levels that became undetectable, as measured in our hospital's clinical laboratory by a commonly employed particle-enhanced turbidometric inhibition assay. An alternative laboratory method yielded appropriate results. Recognizing and resolving erroneously low V trough levels could prevent needless adjustments in dosing that could increase risk for acute kidney injury.

Optimizing Vancomycin Dosing and Monitoring in Neonates and Infants Using Population Pharmacokinetic Modeling

We determined optimal vancomycin starting dose regimens in infants ≤180 days of age to achieve the highest probability of target attainment with an area under the concentration-time curve for 24 h (AUC₂₄) of ≥400 using population pharmacokinetic (PK) modeling. Secondarily, determination of the relationship between serum creatinine (SCR) and vancomycin clearance in neonates was done. A retrospective population PK study was designed and included pediatric patients ≤180 days old who had received vancomycin and had a serum vancomycin concentration sampled. A population PK model was developed using Pumas (v1.0.5). Simulation was performed with various dosing regimens to evaluate the probability of AUC₂₄ target attainment and probability of trough of ≤20 mg/liter, and comparison to published models was performed. Individual clearance estimates, obtained from the final model, were plotted against SCR and faceted by age quartiles to assess the relationship between SCR and vancomycin clearance. A total of 934 patients were included in the study (58.6% male; median age, 43.6 days [range of 0 to 184]; median number of concentration samples, 1 [range of 1 to 29]). A one-compartment model was developed with body weight (WT), SCR, and postmenstrual age (PMA) identified as significant covariates on clearance. Plotting vancomycin clearance versus SCR demonstrated no clear relationship between the two at <10 days postnatal age (PNA). Dosing regimens to attain AUC₂₄ and trough targets were stratified according to SCR for ≥10 days PNA and PMA for <10 days PNA. A vancomycin population PK model was developed for pediatric patients <180 days of age incorporating WT, SCR, and PMA. The relationship between vancomycin clearance and serum creatinine is not clear at <10 days PNA.

Systematic review and meta-analysis to explore optimal therapeutic range of vancomycin trough level for infected paediatric patients with Gram-positive pathogens to reduce mortality and nephrotoxicity risk

The aim of this study was to investigate the association between vancomycin trough level and clinical outcomes (mortality and nephrotoxicity) among infected paediatric patients with Gram-positive pathogens. We systematically searched the Scopus, EMBASE, Cochrane Central Register of Controlled Trials, PubMed and CINAHL databases up to March 2020. A total of seven retrospective cohort or case-control studies were included to compare clinical effects and safety: three studies set the threshold of vancomycin trough level at 10 mg/L and the others set it at 15 mg/L. Our analysis showed that vancomycin trough level of 10-15 mg/L was associated with significantly lower mortality [<10 mg/L vs. ≥10 mg/L, odds ratio (OR) = 3.21, 95% confidence interval (CI) 1.74-5.91; and <15 mg/L vs. ≥15 mg/L, OR = 0.31, 95% CI 0.10-0.95). The high vancomycin trough group (≥10 mg/L or ≥15 mg/L) showed a higher incidence of nephrotoxicity (<10 mg/L vs. ≥10 mg/L, OR = 0.06, 95% CI 0.03-0.12; and <15 mg/L vs. ≥15 mg/L, OR = 0.28, 95% CI 0.12-0.65). This is the first meta-analysis to reveal the optimal therapeutic range of vancomycin trough level in children. Our findings strongly suggest a superior benefit of vancomycin trough of 10-15 mg/L for paediatric patients.

Pediatric Staphylococcus aureus bacteremia: clinical spectrum and predictors of poor outcome

BACKGROUND

Staphylococcus aureus is a common cause of bacteremia, yet the epidemiology, and predictors of poor outcome remain inadequately defined in childhood.

METHODS

ISAIAH is a prospective, cross-sectional study of S. aureus bacteremia (SAB), in children hospitalized in Australia and New Zealand, over 24-months (2017-2018).

RESULTS

Overall, 552 SABs were identified, (incidence 4.4/100,000/yr [95% confidence interval (CI) 2.2-8.8]), with methicillin-susceptible (84%), community onset (78%) infection predominating. Indigenous children (8.1/100,000/yr [CI 4.8-14.4]), those from lower-socioeconomic areas (5.5/100,000/yr [CI 2.8-10.2]) and neonates (6.6/100,000/yr (CI 3.4-11.7) were over-represented. Although 90-day mortality was infrequent, one-third experienced the composite of: length of stay >30 days (26%), ICU admission (20%), relapse (4%), or death (3%).Predictors of mortality included prematurity (aOR 16.8 [CI 1.6-296.9]), multifocal infection (aOR 22.6 [CI 1.4-498.5]), necrotizing pneumonia (aOR 38.9 [CI 1.7 - 1754.6]), multiorgan dysfunction (aOR 26.5 [CI 4.1-268.8]) and empiric-vancomycin (aOR 15.7 [CI 1.6-434.4]); whilst Infectious Diseases (ID) consultation (aOR 0.07 [CI 0.004-0.9]) was protective. Neither MRSA nor vancomycin trough-targets impacted survival; however, empiric-vancomycin was associated with significant nephrotoxicity (OR 3.1 [CI 1.3-8.1]).

CONCLUSIONS

High SAB incidence was demonstrated, with at-risk populations identified for future prioritized care. For the first time in a pediatric setting, necrotizing pneumonia and multifocal infection were predictors of mortality, whilst ID consultation was protective. The need to re-evaluate pediatric vancomycin trough-targets and limit unnecessary empiric-vancomycin exposure, to reduce poor outcomes and nephrotoxicity is highlighted. One in three children experienced considerable SAB morbidity, therefore pediatric inclusion in future SAB comparator trials is paramount to improve outcomes.

Reduced Vancomycin Susceptibility, MRSA and Treatment Failure in Pediatric Staphylococcus aureus Bloodstream Infections

BACKGROUND

Clinical implications of reduced vancomycin susceptibility (RVS) among pediatric Staphylococcus aureus bloodstream infections are unknown.

METHODS

We identified all children at 2 children's hospitals with ≥1 blood culture positive for S. aureus. We compared patient and clinical factors for RVS and non-RVS infections using Wilcoxon rank-sum and chi-squared tests. Treatment failure and the duration of bacteremia for RVS versus non-RVS and for methicillin-resistant Staphylococcus aureus (MRSA) versus methicillin-susceptible Staphylococcus aureus (MSSA) infections were compared using multivariable logistic and Poisson regressions, respectively. For MRSA infections, the association of empiric vancomycin monotherapy with treatment failure was assessed using multivariable logistic regression.

RESULTS

RVS was present in 72% (309/426) of cases. No patient or infection characteristics, including methicillin resistance, were associated with RVS. RVS was associated with an increased duration of bacteremia compared with non-RVS infections, aIRR = 1.15 (95% confidence interval: 1.02-1.30). The odds of treatment failure was similar for RVS and non-RVS infections, aOR = 1.04 (0.62-1.74). In contrast, MRSA infections were more likely to have treatment failure than MSSA infections, aOR = 3.03 (95% confidence interval: 1.84-5.00). For MRSA infections, empiric vancomycin monotherapy was associated with an increased odds of treatment failure compared with non-vancomycin or combination anti-MRSA antibiotics, aOR = 3.23 (1.12-9.26).

CONCLUSIONS

RVS was common and was associated with a longer duration of bacteremia but not with treatment failure. Treatment failure was more common for MRSA than for MSSA bloodstream infections. Empiric vancomycin monotherapy increased the odds of treatment failure for MRSA infections.

Impact of initial vancomycin pharmacokinetic/pharmacodynamic parameters on the clinical and microbiological outcomes of methicillin-resistant Staphylococcus aureus bacteremia in children

Optimal vancomycin exposure is important to minimize treatment failure of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. We aimed to analyze the impact of initial vancomycin pharmacokinetic/pharmacodynamic (PK/PD) parameters, including the initial vancomycin C trough and the area under the curve (AUC)/minimal inhibitory concentration (MIC) on the outcomes of pediatric MRSA bacteremia. The study population consisted of hospitalized children aged between 2 months and 18 years with MRSA bacteremia, in whom C trough was measured at least one time within the time period of January 2010 to March 2018. Demographic profiles, underlying diseases, and clinical/microbiological outcomes were abstracted retrospectively. During the study period, 73 cases of MRSA bacteremia occurred in children with a median age of 12.4 months. Severe clinical outcomes leading to intensive care unit stay and/or use of mechanical ventilation occurred in 47.5% (35/73); all-cause 30-day mortality was 9.7% (7/72). The median dosage of vancomycin was 40.0 mg/kg/day. There was a weak linear relationship between C trough and the corresponding AUC/MIC (r = 0.235). ROC curves for achieving an AUC/MIC of 300 suggested that the initial C trough at 10 μg/mL could be used as a cut-off value with a sensitivity of 90.5% and a specificity of 44%. Although persistent bacteremia at 48-72 hours after vancomycin administration was observed more frequently when the initial C trough was < 10 μg/mL and initial AUC/MIC was < 300, initial AUC/MIC < 300 was the only risk factor associated with persistent bacteremia at 48-72 hours (adjusted OR 3.05; 95% CI, 1.07-8.68). Initial C trough and AUC/MIC were not associated with 30-day mortality. Although there was a weak relationship between C trough and AUC/MIC, initial AUC/MIC < 300 could be used as a predictor of persistent MRSA bacteremia at 48-72 hours. Further prospective data on optimal vancomycin dosing are necessary to improve clinical and microbiological outcomes in pediatric MRSA bacteremia.

A Mitocentric View of the Main Bacterial and Parasitic Infectious Diseases in the Pediatric Population

Infectious diseases occur worldwide with great frequency in both adults and children. Both infections and their treatments trigger mitochondrial interactions at multiple levels: (i) incorporation of damaged or mutated proteins to the complexes of the electron transport chain, (ii) mitochondrial genome (depletion, deletions, and point mutations) and mitochondrial dynamics (fusion and fission), (iii) membrane potential, (iv) apoptotic regulation, (v) generation of reactive oxygen species, among others. Such alterations may result in serious adverse clinical events with great impact on children's quality of life, even resulting in death. As such, bacterial agents are frequently associated with loss of mitochondrial membrane potential and cytochrome c release, ultimately leading to mitochondrial apoptosis by activation of caspases-3 and -9. Using Rayyan QCRI software for systematic reviews, we explore the association between mitochondrial alterations and pediatric infections including (i) bacterial: M. tuberculosis, E. cloacae, P. mirabilis, E. coli, S. enterica, S. aureus, S. pneumoniae, N. meningitidis and (ii) parasitic: P. falciparum. We analyze how these pediatric infections and their treatments may lead to mitochondrial deterioration in this especially vulnerable population, with the intention of improving both the understanding of these diseases and their management in clinical practice.

Acute Hematogenous Osteomyelitis in Children: Clinical Presentation and Management

Acute hematogenous osteomyelitis (AHO) is a common invasive infection encountered in the pediatric population. In addition to the acute illness, AHO has the potential to create long-term morbidity and functional limitations. While a number of pathogens may cause AHO, Staphylococcus aureus is the most common organism identified. Despite the frequency of this illness, little high-quality data exist to guide providers in the care of these patients. The literature is reviewed regarding the epidemiology, microbiology and management of AHO in children. A framework for empiric therapy is provided drawing from the available literature and published guidelines.

Clinical Guideline Highlights for the Hospitalist: Therapeutic Monitoring of Vancomycin

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 RELEASE DATE: Online: March 19, 2020 PRIOR VERSION: 2009 DEVELOPERS: American Society of Health-System Pharmacists (ASHP), the Infectious Diseases Society of America (IDSA), the Pediatric Infectious Diseases Society (PIDS), and the Society of Infectious Diseases Pharmacists (SIDP) FUNDING SOURCE: ASHP, IDSA, PIDS, SIDP TARGET POPULATION: Adults, children, and neonates treated for documented or presumed methicillin-resistant Staphylococcus aureus infection.

A Moving Target-Vancomycin Therapeutic Monitoring

Therapeutic drug monitoring (TDM) has been a common practice to optimize efficacy and safety of vancomycin. While vancomycin trough-only TDM has widely been integrated into pediatric clinical practice since 2009, recently updated vancomycin TDM guidelines published in March 2020 recommend area under the curve (AUC) based TDM for vancomycin instead of trough-only TDM. In this review, we discuss the rationale behind the change in TDM recommendations, describe two approaches for calculating vancomycin AUC in clinical practice, and address considerations for integrating vancomycin AUC TDM into pediatric clinical practice. Our primary goal is to provide pediatric clinicians with a resource for implementing vancomycin AUC monitoring into clinical care.

Vancomycin Therapeutic Drug Monitoring in Children: New Recommendations, Similar Challenges

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 have recently published revised guidelines for the therapeutic monitoring of vancomycin. Previous iterations of the guideline largely focused on targeting vancomycin trough concentrations (VTCs) in the range of 15 to 20 mg/L for therapeutic efficacy. The revised guidelines shift the focus of therapeutic monitoring directly to AUC/MIC-based therapeutic monitoring for children, with a suggestion of a goal AUC/MIC 400 to 800. The primary hesitation in applying these recommendations to children stems from the absence of pediatric clinical data demonstrating correlations with clinical outcomes and either VTC or AUC and no benefit in other secondary outcomes (e.g., recurrence, duration of bacteremia). One can glean indirectly from this that such aggressive dosing and monitoring strategies are unnecessary to achieve therapeutic success in the majority of children with serious methicillin-resistant Staphylococcus aureus infections. Providers should carefully weigh the potential unknown benefits of targeting vancomycin AUC 400 to 800 mg*hr/L in children with the known risks of acute kidney injury associated with increasing the dose of vancomycin as well as the substantial time, effort, and costs of this process.

Intravenous Vancomycin Therapeutic Drug Monitoring in Children: Evaluation of a Pharmacy-Driven Protocol and Collaborative Practice Agreement

BACKGROUND

Vancomycin optimization is challenging, requiring careful therapeutic drug monitoring (TDM) to avoid toxicity and ensure an efficacious concentration. Most prescriptions are empiric and often discontinued within 72 hours, which makes early TDM unnecessary. Although TDM using trough levels is common, the area under the concentration-time curve (AUC) is the preferred pharmacodynamic target. We studied the effect of a pharmacy-driven vancomycin collaborative practice agreement (CPA) at a children's hospital that delayed TDM up to 72 hours and targeted a 2-point 24-hour AUC of ≥400 mg × h/L.

METHODS

We retrospectively reviewed vancomycin courses in patients aged ≥30 days who received vancomycin between April 1, 2011, and August 30, 2017. We implemented the CPA on June 1, 2014. Outcomes included CPA use, use of TDM, dosage adjustments, and development of acute kidney injury; we compared courses given while monitoring only trough levels (TO-TDM) with those given while using the CPA (AUC-TDM). We performed interrupted time series analyses to account for preintervention trends.

RESULTS

We included 2379 courses in the TO-TDM period and 2155 in the AUC-TDM period. During AUC-TDM, 87% of the courses were managed by the CPA. In adjusted interrupted time series analyses, CPA implementation was associated with an initial change in level of -0.265 (95% confidence interval [CI], -0.336 to -0.189) TDM and an initial change in level of -0.332 (95% CI, -0.506 to -0.163) dosage adjustments. The 1-year risk of acute kidney injury decreased after CPA implementation (odds ratio, 0.695 [95% CI, 0.539-0.91]).

CONCLUSION

The pharmacy-driven vancomycin CPA resulted in less monitoring and fewer dose adjustments without increasing AKI.

Practice survey on the use of vancomycin in pediatrics in the New Aquitaine region and guidelines of learned societies

INTRODUCTION

Vancomycin is an old antibiotic whose use is still being debated today. The objective of this work was to establish an inventory of the use of vancomycin in the various pediatric and neonatal hospital services in the New Aquitaine region.

MATERIALS AND METHODS

A declaratory practice survey was conducted in 49 pediatric and neonatal hospital units. These practices were compared with the guidelines of several learned societies.

RESULTS

A total of 36 responses could be analyzed: 12 units (33%) used vancomycin in discontinuous administration, 18 (50%) had opted for continuous infusion, and six used it in both modalities (17%). The reported dosages were highly variable. Blood tests were performed by 26 units (72%), but the target values of the trough serum concentration were also highly variable. After dosing, all units reported adjusting the dosage and re-dosing after modification (26/26). Finally, 21 units (58%) reported taking into account the MIC of the possibly isolated bacterium.

CONCLUSION

Our study shows that vancomycin is used in very different ways from one unit to another, within the same region, including in ways not recommended by the main learned societies. Much work remains to be done to determine the optimal dosages of vancomycin in pediatrics, to set the serum trough concentration of vancomycin values, and to determine whether continuous infusion use is comparable to discontinuous administration in terms of efficacy.

Vancomycin therapeutic drug monitoring in paediatrics

AIM

Vancomycin guidelines for therapeutic drug monitoring (TDM) aim to maximise efficacy while minimising toxicity and resistance. Vancomycin is effective against Staphylococcus aureus when it achieves area under the concentration-time curve (AUC)/minimum inhibitory concentration (MIC) > 400. Studies in children have shown that target trough concentrations poorly correlate to AUC/MIC > 400; however, they are used in practice for clinical convenience. This review in paediatric inpatients aims to audit performance against TDM guidelines and consider what changes are needed to optimise vancomycin monitoring.

METHODS

Vancomycin prescriptions in patients younger than 18 years old were collected over a 15-month period. Primary outcome measures were vancomycin initial dose (mg/kg/day) and the timing and result of first trough concentration (mg/L). Secondary outcome measures were the numbers achieving recommended targets and whether appropriate dose adjustments were made in response to TDM.

RESULTS

A total of 133 courses reached the time when TDM should occur. Average patient age was 6.5 years, and the average initial dose was 52.55 mg/kg/day (range 19.05-86.54 mg/kg). Only 25% of courses (n = 34) had a trough concentration measured at the recommended time. The mean trough concentration was 11.6 mg/L (range < 2.0-39.7). Of 40 patients with a low trough concentration, 50% continued without dose adjustment.

CONCLUSION

As shown in the literature, there is a poor correlation between the vancomycin dose given and the trough concentration achieved. Given that recommendations for trough concentration monitoring are designed to simplify the process yet are poorly adhered to, a strategic plan to address these issues is needed.

Desired vancomycin trough concentration to achieve an AUC0-24 /MIC ≥400 in Chinese children with complicated infectious diseases

A vancomycin steady-state trough concentration (C_min ) of 15-20 mg/L is recommended for achieving a ratio of the 24-hour area under the curve to the minimum inhibitory concentration (AUC_0-24 /MIC) of ≥400 in adults. Since few paediatric data are available, our objectives were to (a) measure the pharmacokinetic indices of vancomycin and (b) determine the correlation between C_min and AUC_0-24 /MIC in paediatric patients. Population-based pharmacokinetic modelling was performed for paediatric patients to estimate the individual parameters. The relationship between C_min and the calculated AUC_0-24 /MIC was explored using linear regression and a probabilistic framework. A sensitivity analysis was also conducted using Monte Carlo simulations. Body-weight significantly influenced the pharmacokinetics of vancomycin. Based on real data and simulations, C_min ranges of 5.0-5.9 and 9.0-12.9 mg/L were associated with AUC_0-24 /MIC ≥400 for MIC values of ≤0.5 and ≤1 mg/L, respectively. Vancomycin regimens of 10 and 15 mg/kg every 6 hours achieved a C_min of 5.0-5.9 mg/L and AUC_0-24 /MIC ≥400 in >90% of the children when MIC was ≤0.5 mg/L. At a MIC of ≤1 mg/L, vancomycin at 15 mg/kg every 6 hours achieved C_min of 9.0-12.9 mg/L and AUC_0-24 /MIC ≥400 in 2.0- and 1.6-fold as many children compared to a dose of 10 mg/kg every 6 hours, respectively. Vancomycin C_min values of 5.0-12.9 mg/L were strongly predictive of achieving AUC_0-24 /MIC ≥400, and rational dosing regimens of 10-15 mg/kg q6h were required in paediatric patients, depending on the pathogen.

Vancomycin drug monitoring in infants with CoNS sepsis-target attainment, microbiological response and nephrotoxicity

OBJECTIVES

To characterize residual vancomycin concentrations (Cmin) and assess the relationships between Cmin, the risk of nephrotoxicity and persistent CoNS sepsis.

METHODS

In this 5-year retrospective study among infants treated with vancomycin, the primary outcome was the proportion of those with a steady state Cmin between 10 and 20 mg/L. The secondary outcomes were nephrotoxicity and persistent CoNS sepsis.

RESULTS

Of 120 infants included, the median first steady state Cmin was 12.4 mg/L and 77 (64%) had a Cmin between 10 and 20 mg/L. Six percent developed nephrotoxicity. This risk was not associated with Cmin. Of the 30 infants with CoNS sepsis, 17 (57%) had persistent bacteremia, and this risk did not correlate significantly with Cmin, CoNS minimal inhibitory concentration (MIC) for vancomycin, or Cmin/MIC.

CONCLUSIONS

The majority of infants achieved targeted levels of vancomycin, but persistent bacteremia was common. We did not identify a Cmin threshold associated with nephrotoxicity, nor with microbiological clearance.

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.

[Effect of augmented renal clearance on plasma concentration of vancomycin and treatment outcome in children with methicillin-resistant Staphylococcus aureus infection]

OBJECTIVE

To investigate the effect of augmented renal clearance (ARC) on plasma concentration of vancomycin, bacteriological outcome, and clinical outcome in children with methicillin-resistant Staphylococcus aureus (MRSA) infection treated by vancomycin.

METHODS

A retrospective analysis was performed for the clinical data of 60 critically ill children who were treated with vancomycin due to MRSA infection from January 2013 to July 2017 and underwent plasma concentration monitoring. According to estimated glomerular filtration rate, these children were divided into an ARC group with 19 children and a normal renal function group with 41 children. The two groups were compared in terms of the use of vancomycin, plasma concentration of vancomycin, and treatment outcome.

RESULTS

The children in the ARC group had an age of 1-12 years, and the ARC group had significantly higher body weight and body surface area than the normal renal function group (P<0.05). Compared with the normal renal function group, the ARC group had a significantly lower initial trough concentration of vancomycin and a significantly lower proportion of children who achieved the effective trough concentration of vancomycin (10-20 mg/L) (P<0.05). There were no significant differences in bacteriological outcome and clinical outcome between the two groups (P>0.05), but the ARC group had significantly longer length of stay in the pediatric intensive care unit (PICU) and length of hospital stay than the normal renal function group (P<0.05).

CONCLUSIONS

ARC can significantly reduce the trough concentration of vancomycin and prolong the length of PICU stay and the length of hospital stay in children with MRSA infection. Idividualized medication should be administered to children with ARC.

Vancomycin Treatment Failure in Children With Methicillin-Resistant Staphylococcus aureus Bacteremia

OBJECTIVES

Limited data exist regarding clinical outcomes of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in children treated with vancomycin. Treatment success in adults correlates best with an area under the curve/minimum inhibitory concentration (AUC₂₄/MIC) ratio ≥400. It is unknown if this relationship is useful in children.

METHODS

Charts of children who received vancomycin ≥5 days for MRSA bacteremia with a steady state trough were reviewed. AUC₂₄/MIC ratios were estimated using 2 different vancomycin clearance equations. Vancomycin treatment failure was defined as persistent bacteremia ≥7 days, recurrent bacteremia within 30 days, or 30-day mortality.

RESULTS

There were 67 bacteremia episodes in 65 patients. Nine (13.4%) met failure criteria: persistent bacteremia (n = 6), recurrent bacteremia (n = 2), 30-day mortality (n = 1). There were no differences between patients receiving <60 mg/kg/day and ≥60 mg/kg/day of vancomycin in median trough (11.9 versus 12.3 mg/L, p = 0.1). Troughs did not correlate well with AUC₂₄/MIC ratios (R ² = 0.32 and 0.22). Patients receiving ≥60 mg/kg/day had greater probability of achieving ratios ≥400. There were no significant differences in median dose (p = 0.8), trough (p = 0.24), or AUC₂₄/MIC ratios (p = 0.07 and p = 0.6) between patients with treatment success and failure.

CONCLUSIONS

Treatment failure was lower than previously reported in children. AUC₂₄/MIC ratios ≥400 were frequently achieved but were not associated with treatment success, dose, or troughs. Prospective studies using standard definitions of vancomycin treatment failure are needed to understand treatment failure in children with MRSA bacteremia.

Use of Body Surface Area for Dosing of Vancomycin

OBJECTIVES

Vancomycin weight-based dosing regimens often fail to achieve therapeutic trough serum concentration in children ≤12 years of age and rigorous studies evaluating efficacy and safety of body surface area (BSA)-based dosing regimens have not been performed. We compared vancomycin trough serum concentrations in pediatric patients receiving a weight- or BSA-based dosing regimen.

METHODS

This was a single-center, retrospective study evaluating pediatric patients, ages 1 to 12 years, who received vancomycin from September 2012 to October 2015. Patients received a minimum of 3 consecutive doses at the same scheduled interval within a dosing regimen prior to a measured vancomycin serum trough concentration. The primary outcome was percentage of initial vancomycin trough concentrations ≥10 mg/L. The secondary outcomes were percentage of supratherapeutic, therapeutic, and subtherapeutic vancomycin serum concentration for all patients, including a subset of overweight and obese patients, and number of nephrotoxic occurrences.

RESULTS

BSA-based dosing regimens resulted in 50% of the initial vancomycin trough concentrations ≥ 10 mg/L compared with 17% for the weight-based dosing regimens (p < 0.0001). No statistically significant differences were noted between the 2 dosing regimens for supratherapeutic, therapeutic, or subtherapeutic trough concentrations for all patients, and for the subset of overweight and obese patients. Nephrotoxic occurrences were noted in 7% of the weight-based dosing regimens compared with none in the BSA-based dosing regimens.

CONCLUSIONS

A BSA-based vancomycin dosing regimen resulted in significantly more initial vancomycin trough concentrations ≥10 mg/L and trended towards higher initial vancomycin trough concentrations without observable nephrotoxicity.

Risk Factors for Complications in Children with Staphylococcus aureus Bacteremia

OBJECTIVES

To determine risk factors for complications in children with Staphylococcus aureus (S aureus) bacteremia, including methicillin resistance.

STUDY DESIGN

Single center, retrospective cohort study of children ≤18 years of age hospitalized with S aureus bacteremia. We compared clinical characteristics and outcomes between those with methicillin-sensitive S aureus (MSSA) and methicillin-resistant S aureus (MRSA) bacteremia. Multivariate regression models identified risk factors associated with developing complications and with longer duration of bacteremia.

RESULTS

We identified 394 episodes of S aureus bacteremia, 279 (70.8%) with MSSA, and 115 (29.2%) with MRSA. Primary site of infection was catheter-related in 34%, musculoskeletal in 30%, skin/soft tissue in 10.2%, pneumonia in 6.4%, and endovascular in 6.6%. Eight children (2.0%) died within 30 days because of S aureus bacteremia, 15 (3.5%) had recurrence within 30 days, and 38 (9.6%) had complications including septic emboli or a metastatic focus of infection. Methicillin resistance was associated with development of a complication (aOR 3.31; 95% CI 1.60-6.85), and catheter-related infections were less likely to be associated with a complication (aOR 0.40; 95% CI 0.15-1.03). In a Poisson regression analysis on duration of bacteremia, methicillin resistance, musculoskeletal infection, endovascular infection, black race, and delayed intervention for source control were significantly associated with longer duration of bacteremia.

CONCLUSIONS

In this cohort of children with S aureus bacteremia, MRSA infections ere associated with longer duration of bacteremia and a higher likelihood of complications.

Association Between Vancomycin Trough Concentrations and Duration of Methicillin-Resistant Staphylococcus aureus Bacteremia in Children

In a multicenter retrospective study, we sought to determine the optimal vancomycin trough concentration that would impact the duration of methicillin-resistant Staphylococcus aureus bacteremia in children. We found that a median vancomycin trough concentration of <10 µg/mL within the first 72 hours may be associated with a longer duration of bacteremia compared to a median trough concentration of ≥10 µg/mL.

Vancomycin associated acute kidney injury in pediatric patients

INTRODUCTION

Vancomycin associated acute kidney injury (vAKI) is a well known complication in pediatric patients. Identification and characterization of the incidence and risk factors for vAKI in the pediatric population would assist clinicians in potentially preventing or mitigating vAKI.

METHODS AND MATERIALS

A 6 year retrospective cohort study was designed. Patients were included if they were < 19 years of age, received vancomycin as inpatients, and had a baseline SCr and one other SCr drawn during and up to 72 hours after the discontinuation of vancomycin. Data collection included patient demographics, vancomycin doses and length of therapy, vancomycin serum concentrations, and concomitant medications. The Kidney Disease Improving Global Outcomes (KDIGO) criteria were used to characterize acute kidney injury. Descriptive statistical methods were used and ordinal logistic regression was employed to determine variables significantly associated with vAKI.

RESULTS

A total of 7,095 patients met study criteria (55.4% male, median age 4.1 years (IQR 0.67-11.2 years)). Mechanical ventilation was used in 7.9% (n = 563) and mortality was 4.9% (n = 344). A total of 153 concomitant medications were identified. A median of 5 (IQR 3-7) SCr values were obtained and median SCr prior to vancomycin was 0.39 (IQR 0.28-0.57) mg/dL (CrCl 134±58 mL/min/1.73m2). Vancomycin was administered for a median of 2 (IQR 1-3) days (14.9±1.6 mg/kg/dose). vAKI was present in 12.2% (n = 862: KDIGO stage 1 (8.30%, n = 589), KDIGO stage 2 (1.94%, n = 138) KDIGO stage 3 (1.89%, n = 134)). Mean vancomycin serum concentration at 6-8 hours after a dose for patients with vAKI (10.7±8.9 mg/L) was significantly, but not clinically different for patients with no vAKI (7.5±6.3 mg/L). (p<0.05) Ordinal logistic regression identified total dose of vancomycin, vancomycin administration in the intensive care unit, and concomitant medication administration as significant for vAKI. In particular, concomitant administration of several different medications, including nafcillin, clindamycin, and acetazolamide, were noted for strong associations with vAKI. (p<0.05).

CONCLUSIONS

Moderate to severe acute kidney injury due to vancomycin is infrequent in children and associated with concomitant medication use and total dose of vancomycin. Serum vancomycin concentrations are not useful predictors of vAKI in the pediatric population.

Nephrotoxicity With Vancomycin in the Pediatric Population: A Systematic Review and Meta-Analysis

BACKGROUND

Vancomycin is frequently used to treat methicillin-resistant Staphylococcus aureus infections in pediatric patients. Vancomycin exposure may lead to an increase in frequency of nephrotoxicity. Our aim was to conduct a systematic review to describe predictors of nephrotoxicity associated with vancomycin, including documented trough concentrations ≥15 mg/L. We also aimed to use a meta-analysis to assess the impact of a vancomycin trough ≥15 mg/L on nephrotoxicity.

METHODS

A literature search was performed using PubMed, Cochrane Library, Embase and Web of Sciences database. We included randomized clinical trials and observational studies evaluating the relationship between vancomycin troughs and nephrotoxicity in pediatric-age patients. Studies not measuring troughs or defining a different cut-off point than 15 mg/L were excluded. Data on age, exclusion criteria, nephrotoxicity definition, risk factors for nephrotoxicity and vancomycin trough levels were extracted from selected papers.

RESULTS

Ten studies were identified for meta-analysis. All subjects had comparatively normal baseline serum creatinine values. Common risk factors identified included elevated (≥15 mg/L) trough levels, renal impairment, hypovolemia and concurrent use of nephrotoxic medications. Troughs ≥15 mg/L increased nephrotoxicity by 2.7-fold (odds ratio (OR), 2.71; 95% confidence interval: 1.82-4.05; I(2) = 40%; Q = 0.09). These odds were further increased among patients in the pediatric intensive care unit (OR, 3.61; 95% confidence interval: 1.21-10.74; I(2) = 45%; Q = 0.18).

CONCLUSIONS

Though the rate of vancomycin-induced nephrotoxicity is increased in pediatric patients with higher vancomycin troughs, other factors such as intensive care unit admission, hypovolemia and concurrent nephrotoxic drug use appear to contribute to the development of nephrotoxicity.

Staphylococcus aureus Central Nervous System Infections in Children

BACKGROUND

Central nervous system (CNS) infections caused by Staphylococcus aureus are uncommon in pediatric patients. We review the epidemiology, clinical features and treatment in 68 patients with a S. aureus CNS infection evaluated at Texas Children's Hospital.

METHODS

Cases of CNS infection in children with positive cerebrospinal fluid cultures or spinal epidural abscess (SEA) for S. aureus at Texas Children's Hospital from 2001 to 2013 were reviewed.

RESULTS

Seventy cases of S. aureus CNS infection occurred in 68 patients. Forty-nine cases (70%) were secondary to a CNS device, 5 (7.1%) were postoperative meningitis, 9 (12.8%) were hematogenous meningitis and 7 (10%) were SEAs. Forty-seven (67.2%) were caused by methicillin-sensitive S. aureus (MSSA) and 23 (32.8%) by methicillin-resistant S. aureus (MRSA). Community-acquired infections were more often caused by MRSA that was clone USA300/pvl. Most patients were treated with nafcillin (MSSA) or vancomycin (MRSA) with or without rifampin. Among patients with MRSA infection, 50% had a serum vancomycin trough obtained with the median level being 10.6 μg/mL (range: 5.4-15.7 μg/mL). Only 1 death was associated with S. aureus infection.

CONCLUSIONS

The epidemiology of invasive of S. aureus infections continues to evolve with MSSA accounting for most of the infections in this series. The majority of cases were associated with neurosurgical procedures; however, hematogenous S. aureus meningitis and SEA occurred as community-acquired infections in patients without predisposing factors. Patients with MRSA CNS infections had a favorable response to vancomycin, but the beneficial effect of combination therapy or targeting vancomycin trough concentrations of 15-20 μg/mL remains unclear.

Epidemiology of Methicillin-Resistant Staphylococcus aureus Bacteremia in Children

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is associated with high rates of treatment failure in adults. The epidemiology, clinical outcomes, and risk factors for treatment failure associated with MRSA bacteremia in children are poorly understood.

METHODS

Multicenter, retrospective cohort study of children ≤18 years hospitalized with MRSA bacteremia across 3 tertiary care children's hospitals from 2007 to 2014. Treatment failure was defined as persistent bacteremia >3 days, recurrence of bacteremia within 30 days, or attributable 30-day mortality. Potential risk factors for treatment failure, including the site of infection, vancomycin trough concentration, critical illness, and need for source control, were collected via manual chart review and evaluated using multivariable logistic regression.

RESULTS

Of 232 episodes of MRSA bacteremia, 72 (31%) experienced treatment failure and 23% developed complications, whereas 5 (2%) died within 30 days. Multivariable analysis of 174 children treated with vancomycin with steady-state vancomycin concentrations obtained found that catheter-related infections (odds ratio [OR], 0.36; 95% confidence interval [CI]: 0.13-0.94) and endovascular infections (OR, 4.35; 95% CI: 1.07-17.7) were associated with lower and higher odds of treatment failure, respectively, whereas a first vancomycin serum trough concentration <10 μg/mL was not associated with treatment failure (OR, 1.34; 95% CI, 0.49-3.66). Each additional day of bacteremia was associated with a 50% (95% CI: 26%-79%) increased odds of bacteremia-related complications.

CONCLUSIONS

Hospitalized children with MRSA bacteremia frequently suffered treatment failure and complications, but mortality was low. The odds of bacteremia-related complications increased with each additional day of bacteremia, emphasizing the importance of achieving rapid sterilization.

The Influence of the Route of Antibiotic Administration, Methicillin Susceptibility, Vancomycin Duration and Serum Trough Concentration on Outcomes of Pediatric Staphylococcus aureus Bacteremic Osteoarticular Infection

BACKGROUND

Bacteremia is often one factor used in deciding the need for prolonged intravenous antimicrobial therapy in osteoarticular infections (OAIs). We examined treatment practices and outcomes of Staphylococcus aureus bacteremic osteoarticular infections (BOAIs) evaluated at Texas Children's Hospital.

METHODS

Cases of acute hematogenous OAI in children with positive blood cultures for S. aureus at Texas Children's Hospital between 2011 and 2014 were reviewed. Orthopedic complications included chronic osteomyelitis, growth arrest, pathologic fracture, avascular necrosis and chronic dislocation. Acute kidney injury was defined as a doubling of the baseline creatinine.

RESULTS

One hundred and ninety-two cases of S. aureus OAI were identified with 102 cases of BOAI included [35 methicillin-resistant S. aureus (MRSA)]. Twenty-five patients were discharged home on oral antibiotics. Patients discharged on oral antibiotics had a shorter duration of fever, had a more rapid decline in C-reactive protein and were less likely to have MRSA. The frequency of orthopedic complications did not increase in patients who received early transition to oral antibiotics. For patients with MRSA bacteremia, the rates of complications between those who received ≥7 days versus <7 days of vancomycin did not differ. Vancomycin serum troughs >15 µg/mL were not associated with a decreased duration of fever, bacteremia or hospitalization, need for repeat operation or orthopedic complications but were associated with acute kidney injury.

CONCLUSIONS

S. aureus BOAIs are associated with substantial morbidity. Early transition to oral therapy may be a safe option for select patients with S. aureus BOAI, including those due to MRSA. Prolonged courses of vancomycin and vancomycin troughs >15 μg/mL were not associated with improved outcomes for MRSA OAI.

Predictors of Adverse Outcomes in Children With Staphylococcus aureus Bacteremia

OBJECTIVES

Staphylococcus aureus bacteremia is a common infection, associated with significant morbidity and mortality in children. Factors associated with adverse treatment outcomes are poorly understood in the pediatric population.

METHODS

Our study compared clinical and microbiologic characteristics of children admitted during a 5-year period (2007-2012) to a large university-based hospital and found to have S aureus bacteremia with outcome measures, in order to identify risk factors associated with treatment failure (defined as 30-day mortality, delayed microbiologic resolution, or recurrence of S aureus bacteremia within 60 days of completing effective antibiotic therapy).

RESULTS

In all, 71 patients were found to have S aureus bacteremia, and of these, 17 patients (24%) experienced treatment failure. Based on the logistic regression model, only high vancomycin minimum inhibitory concentration in combination with a high-risk source of infection (i.e., infected graft or device, intra-abdominal infection, or respiratory tract infection) was significantly associated with risk of treatment failure.

CONCLUSIONS

Infection associated with a high-risk source may increase the chance of treatment failure in pediatric patients with S aureus bacteremia. Vancomycin minimum inhibitory concentration alone was not found to be a predictor of treatment outcomes.