Cefadroxil and cephalexin pharmacokinetics and pharmacodynamics in children with musculoskeletal infections.

Cephalexin, a first-generation cephalosporin, is the first-line oral therapy for children with musculoskeletal infections due to methicillin-susceptible Staphylococcus aureus (MSSA). Cefadroxil, a similar first-generation cephalosporin, is an attractive alternative to cephalexin given its longer half-life. In this study, we describe the comparative pharmacokinetics (PK) and pharmacodynamics (PD) of cephalexin and cefadroxil in children with musculoskeletal infections. Children aged 6 months to 18 years with a musculoskeletal infection were enrolled in a prospective, open-label, crossover PK study and given single oral doses of cefadroxil (50-75 mg/kg up to 2,000 mg) and cephalexin (50 mg/kg up to 1,375 mg). Population PK models were developed and used for dosing simulations. Our primary PD target was the achievement of free antibiotic concentrations above the minimum inhibitory concentration (fT >MIC) for 40% of the day for MICs ≤ 4 mg/L. PK of cephalexin (n = 15) and cefadroxil (n = 14) were best described using a one-compartment, first-order absorption model, with a lag time component for cefadroxil. PK parameters were notable for cefadroxil's longer half-life (1.61 h) than cephalexin's (1.10 h). For pediatric weight bands, our primary PD target was achieved by cephalexin 25 mg/kg/dose, maximum 750 mg/dose, administered three times daily and cefadroxil 40 mg/kg/dose, maximum 1,500 mg/dose, administered twice daily. More aggressive dosing was required to achieve higher PD targets. Among children with musculoskeletal infections, oral cephalexin and cefadroxil achieved PD targets for efficacy against MSSA. Given less frequent dosing, twice-daily cefadroxil should be further considered as an alternative to cephalexin for oral step-down therapy for serious infections due to MSSA.

Impact of Organism Reporting from Endotracheal Aspirate Cultures on Antimicrobial Prescribing Practices in Mechanically Ventilated Pediatric Patients.

Endotracheal aspirate cultures (EACs) help diagnose lower respiratory tract infections in mechanically ventilated patients but are limited by contamination with normal microbiota and variation in laboratory reporting. Increased use of EACs is associated with increased antimicrobial prescribing, but the impact of microbiology reporting on prescribing practices is unclear. This study was a retrospective analysis of EACs from mechanically ventilated patients at Children's Hospital Colorado (CHCO) admitted between 1 January 2019 and 31 December 2019. Chart review was performed to collect all culture and Gram stain components, as well as antibiotic use directed to organisms in culture. Reporting concordance was determined for each organism using American Society for Microbiology guidelines. Days of therapy were calculated for overreported and guideline-concordant organisms. A multivariable model was used to assess the relationship between organism reporting and total days of therapy. Overall, 448 patients with 827 EACs were included in this study. Among patients with tracheostomy, 25 (8%) organisms reported from EACs were overreported and contributed 48 days of excess therapy, while 227 (29%) organisms from the EACs of endotracheally intubated patients were overreported, contributing 472 excess days of therapy. After adjustment, organism overreporting was associated with a >2-fold-higher rate of antimicrobial therapy than guideline-concordant reporting (incident rate ratio [IRR], 2.83; 95% confidence interval [CI], 1.23, 6.53; P < 0.05). Overreported organisms from respiratory cultures contribute to excess antimicrobial therapy exposure in mechanically ventilated patients. Microbiology laboratories have an opportunity to mitigate antimicrobial overuse through standardized reporting practices.

Characteristics of Children With Culture Negative Acute Hematogenous Musculoskeletal Infections.

BACKGROUND: Identifying the causative pathogen for acute hematogenous musculoskeletal infections (MSKIs) allows for directed antimicrobial therapy and diagnostic confidence. However, 20% to 50% of children with acute MSKIs remain culture negative. The objective of this study was to compare characteristics of culture negative MSKI patients to those where a pathogen is identified. METHODS: Electronic medical records of children admitted between July 2014 to September 2018 to a single quaternary care pediatric hospital with acute MSKIs were retrospectively reviewed. Clinical and demographic characteristics were compared between culture positive and culture negative MSKIs. RESULTS: A total of 170 patients were included of whom 43 (25%) were culture negative. All culture negative patients had at least 1 culture type obtained, and the majority (84%) had both blood and source cultures performed. When compared with patients with a causative pathogen identified, culture negative patients were younger (2.3 vs. 9.8 y), smaller (13.5 vs. 31.6 kg), less likely to be febrile on arrival (56% vs. 77%), less likely to have an abscess on imaging (23% vs. 48%), and were more likely to have uncomplicated septic arthritis (35% vs. 8%). No critically ill patient was culture negative. Seven culture negative patients had additional Kingella kingae testing performed, none of which were positive. CONCLUSIONS: Despite targeted and standardized efforts to identify causative bacteria, 25% of children with acute MSKIs never have a pathogen identified. Culture negative patients are younger, less febrile, are less likely to have an abscess, and more likely to have isolated septic arthritis. LEVEL OF EVIDENCE: This is a retrospective cohort study interested in identifying patient characteristics that predict rate of culture positivity for acute MSKIs. This study meets criteria for Level II evidence.

Indirect Standardization as a Case Mix Adjustment Method to Improve Comparison of Children's Hospitals' Antimicrobial Use.

Antimicrobial use (AU) in days of therapy per 1000 patient-days (DOT/1000 pd) varies widely among children's hospitals. We evaluated indirect standardization to adjust AU for case mix, a source of variation inadequately addressed by current measurements. Hospitalizations from the Pediatric Health Information System were grouped into 85 clinical strata. Observed to expected (O:E) ratios were calculated by indirect standardization and compared with DOT/1000 pd. Outliers were defined by O:E z-scores. Antibacterial DOT/1000 pd ranged from 345 to 776 (2.2-fold variation; interquartile range [IQR] 552-679), whereas O:E ratios ranged from 0.8 to 1.14 (1.4-fold variation; IQR 0.93-1.05). O:E ratios were moderately correlated with DOT/1000 pd (correlation estimate 0.44; 95% confidence interval, 0.19-0.64; P = .0009). Using indirect standardization to adjust for case mix reduces apparent AU variation and may enhance stewardship efforts by providing adjusted comparisons to inform interventions.

The Pediatric Endotracheal Aspirate Culture Survey (PETACS): Examining Practice Variation across Pediatric Microbiology Laboratories in the United States.

In the absence of evidence-based laboratory guidelines, the workup and interpretation of tracheal aspirate (TA) cultures remains controversial and confusing within the fields of clinical microbiology, infectious diseases, and critical care. Between 22 January and 24 February 2020, we conducted a national, web-based survey of microbiology laboratory personnel in free-standing pediatric hospitals and adult hospitals containing pediatric facilities regarding the laboratory practices used for TA specimens. We hypothesized there would be substantial center-level variability in laboratory processing of TA cultures. The response rate for the survey was 48% (73/153). There was a high level of variability in the criteria used for all processes, including specimen receipt, Gram staining, and culture reporting. Most respondents (77%) reported they do not reject TA specimens based on Gram stain criteria, and 44% of labs do not require that a minimum number of Gram stain fields be reviewed prior to reporting results. Overall, nonacademic hospital laboratories and pediatric-only laboratories are more likely to identify, report, and perform susceptibility testing on organisms from TA cultures, regardless of organism quantity or predominance. There is a substantial amount of process variability among pediatric microbiology laboratories that affects TA culture reporting, and which guides treatment decisions. This variation within and among labs makes clinical outcome studies related to TA cultures difficult to interpret. This study serves as a pragmatic step in informing the development of robust clinical guidelines. Clinical outcome and implementation studies are necessary to determine the effectiveness of guidelines for TA cultures.

Sustainability of Handshake Stewardship: Extending a Hand Is Effective Years Later.

BACKGROUND: Children's Hospital Colorado created a unique method of antimicrobial stewardship, called handshake stewardship, that effectively decreased hospital anti-infective use and costs in its pilot year (2013). Handshake stewardship is distinguished by: (1) the lack of prior authorization; (2) a review of all prescribed anti-infectives; (3) a shared review by the physician and the pharmacist; and (4) a daily, rounding-based, in-person approach to supporting providers. We sought to reevaluate the outcomes of the program after 5 years of experience, totaling 8 years of data. METHODS: We retrospectively measured anti-infective (antibiotic, antiviral, antifungal) use hospital-wide by unit and by drug for an 8-year period spanning October 2010 to October 2018. Aggregated monthly use was measured in days of therapy per thousand patient days (DOT/1000 PD). The percentage of children admitted ever receiving an anti-infective was also measured, as well as severity-adjusted mortality, readmissions, and lengths of stay. RESULTS: Hospital-wide mean anti-infective use significantly decreased, from 891 (95% confidence interval [CI] 859-923) in the pre-implementation phase to 655 (95% CI 637-694) DOT/1000 PD in post-implementation Year 5; in a segmented regression time series analysis, this was a rate of -2.6 DOT/1000 PD (95% CI -4.8 to -0.4). This is largely attributable to decreased antibacterial use, from 704 (95% CI 686-722) to 544 (95% CI 525 -562) DOT/1000 PD. The percentage of children ever receiving an anti-infective during admission likewise declined, from 65% to 52% (95% CI 49-54). There were no detrimental effects on severity adjusted mortality, readmissions, or lengths of stay. CONCLUSIONS: The handshake method is an effective and sustainable approach to stewardship.

Anti-infective Waste in a Pediatric Institution: Pinpointing Problems in the Process.

Purpose: At Children's Hospital Colorado (CHCO), there are approximately 40 000 inpatient anti-infective orders every year resulting over 100 000 dispenses. Significant quantities of anti-infectives are wasted, incurring roughly $100 000 in waste annually. Identifying areas for improvement will result in cost savings and ameliorate the impact of drug shortages. Summary: This descriptive report discusses the reasons for anti-infective waste at a free-standing, quaternary-care, pediatric hospital. The anti-infectives with the highest cost in waste ($) included meropenem ($38 084), micafungin ($21 690), amphotericin B liposome ($15 913). An internal audit of CHCO anti-infective waste revealed that drugs are wasted for the following reasons: patient discharge, medication order discontinuation or change, and misplaced doses. Conclusion: The CHCO Antimicrobial Stewardship Program and the Pharmacy have proposed 4 process improvement measures that will target anti-infective waste to reduce pharmaceutical waste and hospital costs. These measures may be applicable to other drug classes that likely suffer from a similar proportion of waste.

Variability in Antibiotic Use Across PICUs.

OBJECTIVES: To characterize and compare antibiotic prescribing across PICUs to evaluate the degree of variability. DESIGN: Retrospective analysis from 2010 through 2014 of the Pediatric Health Information System. SETTING: Forty-one freestanding children's hospital. SUBJECTS: Children aged 30 days to 18 years admitted to a PICU in children's hospitals contributing data to Pediatric Health Information System. INTERVENTIONS: To normalize for potential differences in disease severity and case mix across centers, a subanalysis was performed of children admitted with one of the 20 All Patient Refined-Diagnosis Related Groups and the seven All Patient Refined-Diagnosis Related Groups shared by all PICUs with the highest antibiotic use. RESULTS: The study included 3,101,201 hospital discharges from 41 institutions with 386,914 PICU patients. All antibiotic use declined during the study period. The median-adjusted antibiotic use among PICU patients was 1,043 days of therapy/1,000 patient-days (interquartile range, 977-1,147 days of therapy/1,000 patient-days) compared with 893 among non-ICU children (interquartile range, 805-968 days of therapy/1,000 patient-days). For PICU patients, the median adjusted use of broad-spectrum antibiotics was 176 days of therapy/1,000 patient-days (interquartile range, 152-217 days of therapy/1,000 patient-days) and was 302 days of therapy/1,000 patient-days (interquartile range, 220-351 days of therapy/1,000 patient-days) for antimethicillin-resistant Staphylococcus aureus agents, compared with 153 days of therapy/1,000 patient-days (interquartile range, 130-182 days of therapy/1,000 patient-days) and 244 days of therapy/1,000 patient-days (interquartile range, 203-270 days of therapy/1,000 patient-days) for non-ICU children. After adjusting for potential confounders, significant institutional variability existed in antibiotic use in PICU patients, in the 20 All Patient Refined-Diagnosis Related Groups with the highest antibiotic usage and in the seven All Patient Refined-Diagnosis Related Groups shared by all 41 PICUs. CONCLUSIONS: The wide variation in antibiotic use observed across children's hospital PICUs suggests inappropriate antibiotic use.

A Handshake From Antimicrobial Stewardship Opens Doors for Infectious Disease Consultations.

Implementation of a unique in-person pediatric antimicrobial stewardship program was associated with a significant increase in infectious disease consultations at a quaternary care children's hospital. This study demonstrates that antimicrobial stewardship programs support, and do not compete with, infectious disease programs.

Anti-infective Acquisition Costs for a Stewardship Program: Getting to the Bottom Line.

BACKGROUND: Though antimicrobial stewardship programs (ASPs) are in place for patient safety, financial justification is often required. In 2016, the Infectious Diseases Society of America (IDSA) recommended that anti-infective costs be measured by patient-level administration data normalized for patient census. Few publications use this methodology. Here, we aim to compare 3 methods of drug cost analysis during 3 phases of an ASP as an example of this recommendation's implementation. METHODS: At a freestanding pediatric hospital, we retrospectively assessed anti-infective cost using pharmacy purchasing data, patient-level administration data from the electronic medical record (EMR), and patient-level administration data from the Pediatric Hospital Information Systems (PHIS) database, all normalized to patient census. Costs pre-ASP, while planning the ASP, and post-ASP were then compared for each method. RESULTS: Significant differences in costs between the methods were observed. Pharmacy purchasing endorsed minimal financial benefit (decrease planning to post-ASP of $590 dollars per 1000 patient-days), while the EMR and PHIS data endorsed a decrease of $12785 and $21380 per 1000 patient-days, respectively, for a total yearly cost savings of $54656 for pharmacy purchasing data, $1184336 for EMR data, and $2117522 for PHIS data. CONCLUSIONS: Pharmacy purchasing data underestimated cost savings compared with EMR and PHIS data, while EMR and PHIS data were comparable in magnitude of savings. At Children's Hospital Colorado, savings justified the full cost of the ASP. EMR patient-level administration data, normalized to patient census, offers a readily available and standardized measure of anti-infective costs over time.

Implementation of Rapid Molecular Infectious Disease Diagnostics: the Role of Diagnostic and Antimicrobial Stewardship.

New rapid molecular diagnostic technologies for infectious diseases enable expedited accurate microbiological diagnoses. However, diagnostic stewardship and antimicrobial stewardship are necessary to ensure that these technologies conserve, rather than consume, additional health care resources and optimally affect patient care. Diagnostic stewardship is needed to implement appropriate tests for the clinical setting and to direct testing toward appropriate patients. Antimicrobial stewardship is needed to ensure prompt appropriate clinical action to translate faster diagnostic test results in the laboratory into improved outcomes at the bedside. This minireview outlines the roles of diagnostic stewardship and antimicrobial stewardship in the implementation of rapid molecular infectious disease diagnostics.

At the break point: What needs to change for antimicrobial stewardship program pharmacists?

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

Time to positivity of blood cultures in a level IV NICU varies based on organism category and population subgroups: is a 36-hour rule out safe?

BACKGROUND: Time to positivity (TTP) of blood cultures and organism characteristics may be different in a Level IV NICU population. METHODS: Retrospective study of 309 Level IV NICU positive blood cultures between January 2012 to December 2018 describing TTP and organism characteristics. RESULTS: Median TTP [IQR] was 21.1 [14.3, 25.2] hours, with 91.2% positive at 36 h, and 96.1% positive at 48 h. Gram negative definite pathogens had the shortest TTP (13.0 [11.4, 15.4] hours) compared to gram positive definite pathogens (16.3 [13.0, 22.4] hours). TTP for treated gram positive commensal organisms (22.3 [20.1, 30.4] hours) and those considered contaminants (23.6 [21.4, 26.0] hours), was significantly longer than both gram positive and negative definite pathogens. CONCLUSION: When antimicrobials are initiated due to concern for bacteremia and blood cultures have not identified a causative pathogen at 36 h, antimicrobials may be safely discontinued in the majority of Level IV NICU patients.

Clinical Outcomes Associated with Amoxicillin Treatment for Acute Otitis Media in Children.

BACKGROUND: Acute otitis media (AOM) is the most common reason children are prescribed antibiotics. Bacteria that produce beta-lactamase are an increasingly frequent cause of AOM and may be resistant to amoxicillin, the currently recommended treatment for AOM. We aimed to evaluate the clinical outcomes of children treated with amoxicillin for AOM and assessed whether outcomes vary by infecting pathogen or beta-lactamase production. METHODS: 205 children 6-35 months old diagnosed with AOM and prescribed amoxicillin were included. Bacterial culture and qualitative multiplex real-time polymerase chain reaction were performed on nasopharyngeal swabs collected at enrollment. Parents completed surveys assessing symptoms, antibiotic adherence, and potential adverse events. The primary outcome was treatment failure with amoxicillin. Secondary outcomes included recurrence, symptom improvement, resolution, and adverse drug events (ADE). RESULTS: 8 children (5.4%) experienced treatment failure and 14 (6.8%) had recurrence. By day 5, 152 (74.1%) children had symptom improvement and 97 (47.3%) had resolution. Parents reported ADE for 56 (27.3%) children. Among 149 children who did not take any amoxicillin before enrollment, 98 (65.8%) had one or more beta-lactamase-producing bacteria. Common bacterial otopathogens were Moraxella catarrhalis (79, 53.0%), Streptococcus pneumoniae (51, 34.2%), Haemophilus influenzae (30, 20.1%), and Staphylococcus aureus (21, 14.1%). Treatment failure did not differ between children that did (5, 5.1%) and did not (3, 5.9%) have beta-lactamase-producing otopathogens (p = .05). CONCLUSIONS: Among children diagnosed with AOM treated with amoxicillin, treatment failure was uncommon and did not differ by pathogen or beta-lactamase production. These data support guidance recommending amoxicillin despite an increasing prevalence of beta-lactamase-producing bacteria.

Microbiology Culture Results and Antibiotic Prescribing in Pediatric Patients With Lymphadenitis.

BACKGROUND: Bacterial lymphadenitis is a common reason for antibiotic treatment and hospitalization in children. The literature available addressing the bacterial etiology of lymphadenitis recommends the use of narrow-spectrum agents to cover common pathogens. We suspect that patients at our institution receive unnecessarily broad-spectrum antimicrobial agents. The primary objective of this study was to characterize the microbiology and antibiotic use in lymphadenitis patients. METHODS: Retrospective review of children admitted over a 10-year period with an International Classification of Diseases Ninth or Tenth Edition code for lymphadenitis. Patients were included if they were <18 years old, admitted to the inpatient ward, and had intraoperative lymph node cultures collected. RESULTS: A total of 131 patients admitted with lymphadenitis had lymph node cultures collected and were included. Seventy-two (72/131; 55%) patients had positive lymph node culture results with pathogenic bacteria. The predominant pathogens were Staphylococcus aureus (56/72; 77.8%) and Streptococcus pyogenes (10/72; 13.9%). The most common inpatient empirical regimen was ampicillin-sulbactam. Of the 72 patients with typical pathogens identified, 80.6% were sensitive to a first-generation cephalosporin, whereas 86.1% were sensitive to a ß-lactam/ß-lactamase inhibitor. CONCLUSION: Patients presenting to our institution with acute bacterial lymphadenitis were predominantly found to have methicillin-susceptible S. aureus lymphadenitis that could be empirically treated with cefazolin. At our institution, there is little advantage to the most commonly used broad-spectrum agent, ampicillin-sulbactam.

Reliability of nasopharyngeal PCR for the detection of otopathogens in children with uncomplicated acute otitis media compared to culture.

Otopathogens in acute otitis media (AOM) have implications for care because the likelihood of resolution without antibiotics and optimal antibiotic agent varies by microorganism. We aimed to determine the sensitivity, specificity, positive predictive value, and negative predictive value of nasopharyngeal (NP) qualitative polymerase chain reaction (PCR) for common bacterial otopathogens in children with AOM compared to NP culture. NP flocked swabs collected from enrolled children aged 6 to 35 months with uncomplicated AOM in Denver, CO were tested by culture and multiplex PCR. The sensitivity and negative predictive value of PCR using culture as a reference were high (H. influenzae 93.3%, 98.0%; S. pneumoniae 94.2%, 95.1%; M. catarrhalis 92.3%, 86.4%); whereas the specificity and positive predictive value were lower and varied by organism (54.2%-84.1%, 55.1%-69.2%, respectively). PCR detected 1.5 times more organisms than culture. NP PCR has a high predictive value for excluding otopathogens compared to culture and warrants exploration as a diagnostic tool.

Using Administrative Billing Codes to Identify Acute Musculoskeletal Infections in Children.

BACKGROUND AND OBJECTIVES: Acute hematogenous musculoskeletal infections (MSKI) are medical emergencies with the potential for life-altering complications in afflicted children. Leveraging administrative data to study pediatric MSKI is difficult as many infections are chronic, nonhematogenous, or occur in children with significant comorbidities. The objective of this study was to validate a case-finding algorithm to accurately identify children hospitalized with acute hematogenous MSKI using administrative billing codes. METHODS: This was a multicenter validation study using the Pediatric Health Information System (PHIS) database. Hospital admissions for MSKI were identified from 6 PHIS hospitals using discharge diagnosis codes. A random subset of admissions underwent manual chart review at each site using predefined criteria to categorize each admission as either "acute hematogenous MSKI" (AH-MSKI) or "not acute hematogenous MSKI." Ten unique coding algorithms were developed using billing data. The sensitivity and specificity of each algorithm to identify AH-MSKI were calculated using chart review categorizations as the reference standard. RESULTS: Of the 492 admissions randomly selected for manual review, 244 (49.6%) were classified as AH-MSKI and 248 (50.4%) as not acute hematogenous MSKI. Individual algorithm performance varied widely (sensitivity 31% to 91%; specificity 52% to 98%). Four algorithms demonstrated potential for future use with receiver operating characteristic area under the curve greater than 80%. CONCLUSIONS: Identifying children with acute hematogenous MSKI based on discharge diagnosis alone is challenging as half have chronic or nonhematogenous infections. We validated several case-finding algorithms using administrative billing codes and detail them here for future use in pediatric MSKI outcomes.

Extending the Reach of Antimicrobial Stewardship to Pediatric Patients.

Guidance for developing and implementing antimicrobial stewardship programs for children is lacking. This review article describes unique considerations for planning antimicrobial management of children that may impact stewardship strategies. A variety of methods and training tools are described along with metrics specific to measuring antibiotic use and outcomes in children. Handshake stewardship is specifically explained and is considered a best practice. Information on stewardship in unique settings, including the neonatal intensive care unit and outpatient settings, are included.

Identifying predictors for source culture positivity in children with acute musculoskeletal infections.

OBJECTIVES: Identifying the causative bacterial pathogen for children with acute hematogenous musculoskeletal infections (MSKIs) allows for improved care. The purpose of our study was to determine if clinical markers could predict which patients will have a causative pathogen found on source culture alone, thus being highest yield to undergo operative diagnostic procedures. METHODS: A single-center, retrospective cohort study was performed. Medical records for patients between 6 months and 18 years of age admitted between July 2014 and September 2018 with a discharge diagnosis of acute osteomyelitis, septic arthritis, or pyomyositis were reviewed. Patients were stratified based on results of blood and source cultures. Predictors of interest were screened on a univariable basis with significant predictors retained in a multivariate analysis. RESULTS: There were 170 patients included. No predictors were significantly associated with increased odds of having a causative pathogen found on source culture alone. Degree of C-reactive protein elevation and history of fever were associated with decreased odds of being source culture positive, OR (95% CI); 0.92 (0.87, 0.98) and 0.39 (0.19, 0.81), respectively. CONCLUSIONS: Predictive modeling failed to identify children with MSKIs whose causative pathogen was found by source culture alone. It is difficult to predict which MSKI patients will be highest yield for operative diagnostic procedures.