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Background: Current vancomycin monitoring guidelines recommend monitoring 24-hour area under the concentration-time curve (AUC) to minimum inhibitory concentration ratios for patients with serious methicillin-resistant Staphylococcus aureus infections. However, there are sparse data on the safety, feasibility, and efficacy of vancomycin AUC monitoring for outpatients. Traditional AUC pharmacokinetic calculations require 2 concentrations, while bayesian software allows for single-concentration AUC estimations., Methods: We conducted a single-center, quasi-experimental, interrupted time series study of patients enrolled in the outpatient parenteral antimicrobial therapy program at our institution for vancomycin management. Our institution implemented a pharmacist-driven vancomycin AUC monitoring program from September 2019 to February 2020, and again from September 2022 to March 2023. Patients enrolled underwent vancomycin monitoring using an AUC goal of 400-600 mg⋅h/L, estimated through bayesian modeling. Patients enrolled in the outpatient parenteral antimicrobial therapy program from July 2021 through August 2022 for trough-based monitoring were used for comparison. The primary outcome was nephrotoxicity incidence, defined as a serum creatinine increase by ≥0.5 mg/dL or ≥50% during outpatient vancomycin therapy., Results: We enrolled 63 patients in the AUC group and 60 patients in the trough-based group. Nephrotoxicity was significantly lower in the AUC cohort (6.3% vs 23.3%; P = .01). The number of unusable vancomycin concentrations was also significantly lower in the AUC cohort (0% vs 6%; P < .01). There was no difference in composite 90-day all-cause mortality or readmission (33.3% vs 38.3%; P = .56)., Conclusions: Following implementation of a pharmacist-driven AUC monitoring program, patients were less likely to develop nephrotoxicity during outpatient vancomycin therapy., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: Dalbavancin has been used off-label to treat invasive bacterial infections in vulnerable populations like people who use drugs (PWUD) because of its broad gram-positive coverage and unique pharmacological properties. This retrospective, multisite study examined clinical outcomes at 90 days in PWUD versus non-PWUD after secondary treatment with dalbavancin for bacteremia, endocarditis, osteomyelitis, septic arthritis, and epidural abscesses., Methods: Patients at 3 teaching hospitals who received dalbavancin for an invasive infection between March 2016 and May 2022 were included. Characteristics of PWUD and non-PWUD, infection highlights, hospital stay and treatment, and outcomes were compared using χ 2 for categorical variables, t test for continuous variables, and nonparametric tests where appropriate., Results: There were a total of 176 patients; 78 were PWUD and 98 were non-PWUD. PWUD were more likely to have a patient-directed discharge (26.9% vs 3.1%; P < .001) and be lost to follow-up (20.5% vs 7.14%; P < .01). Assuming loss to follow-up did not achieve clinical cure, 73.1% of PWUD and 74.5% of non-PWUD achieved clinical cure at 90 days ( P = .08)., Conclusions: Dalbavancin was an effective treatment option for invasive gram-positive infections in our patient population. Despite higher rates of patient-directed discharge and loss to follow-up, PWUD had similar rates of clinical cure at 90 days compared to non-PWUD., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Nontuberculous mycobacteria (NTM) can cause a variety of infections, including serious pulmonary disease. Treatment encompasses polypharmacy, with a targeted regimen of 2-5 active medications, depending on site of infection, species, and clinical characteristics. Medications may include oral, intravenous, and inhalational routes. Medication acquisition can be challenging for numerous reasons, including investigational status, limited distribution models, and insurance prior authorization. Additionally, monitoring and managing adverse reactions and drug interactions is a unique skill set. While NTM is primarily medically managed, clinicians may not be familiar with the intricacies of medication selection, procurement, and monitoring. This review offers insights into the pharmacotherapeutic considerations of this highly complex disease state, including regimen design, medication acquisition, safety monitoring, relevant drug-drug interactions, and adverse drug reactions., Competing Interests: Potential conflicts of interest. C.G.R. has received speaker fees from Insmed. B.C. holds stock or stock options in Pfizer, Merck, Viatris, Organon, and GE HealthCare. M.V.M. serves as a consultant for BD Diagnostics, GSK, and Cidara. M.V.M. has served on an advisory board for Melinta, Pfizer, and Merck. M.V.M. has received research funding from Merck. M.V.M. has received an honorarium from Paratek. All other authors report no potential conflicts., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: Previous studies identified a rapid decrease in valproate serum concentrations when coadministered with a carbapenem; however, the specific consequences and subsequent therapy adjustments are not well described. We aimed to investigate the clinical and therapeutic implications of the carbapenem-valproate drug-drug interaction., Methods: This retrospective analysis included data from 2 large academic medical centers during January 2017 to June 2022. The primary outcome was incidence of seizures or behavioral events stratified by valproate indication. All adult patient encounters with concomitant administration of any carbapenem antimicrobial and valproate were included. Patients without prolonged exposure to valproate prior to hospitalization, without valproate levels pre- and post-carbapenem administration, with an admitting diagnosis of seizure, with exposure to other agents that decrease valproate concentrations, or who had a seizure during the hospitalization prior to carbapenem exposure were excluded., Results: Two hundred fifty-eight episodes of concomitant use among 78 unique adult patients were included. Valproate was used for seizure control in 41 patients (52.6%) and for mood-related disorders in 37 (47.4%). In those prescribed valproate for its antiepileptic properties, seizures occurred following carbapenem administration in 46.3% of encounters. In those taking valproate for mood-related disorders, 50.8% met the primary endpoint of behavioral disturbance., Conclusions: Our study demonstrates significant clinical implications of the carbapenem-valproate interaction. Clinicians should be aware of this interaction and consider alternative antimicrobial and/or antiepileptic agents whenever possible. Adding or increasing doses of antiepileptic agents and/or consultation with a neurologist prior to concomitant use should be considered when this combination cannot be avoided., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: Bacillus cereus is a ubiquitous gram-positive rod-shaped bacterium that can cause sepsis and neuroinvasive disease in patients with acute leukemia or neutropenia., Methods: A single-center retrospective review was conducted to evaluate patients with acute leukemia, positive blood or cerebrospinal fluid test results for B cereus , and abnormal neuroradiographic findings between January 2018 and October 2022. Infection control practices were observed, environmental samples obtained, a dietary case-control study completed, and whole genome sequencing performed on environmental and clinical Bacillus isolates., Results: Five patients with B cereus neuroinvasive disease were identified. All patients had acute myeloid leukemia (AML), were receiving induction chemotherapy, and were neutropenic. Neurologic involvement included subarachnoid or intraparenchymal hemorrhage or brain abscess. All patients were treated with ciprofloxacin and survived with limited or no neurologic sequelae. B cereus was identified in 7 of 61 environmental samples and 1 of 19 dietary protein samples-these were unrelated to clinical isolates via sequencing. No point source was identified. Ciprofloxacin was added to the empiric antimicrobial regimen for patients with AML and prolonged or recurrent neutropenic fevers; no new cases were identified in the ensuing year., Conclusions: B cereus is ubiquitous in the hospital environment, at times leading to clusters with unrelated isolates. Fastidious infection control practices addressing a range of possible exposures are warranted, but their efficacy is unknown and they may not be sufficient to prevent all infections. Thus, including B cereus coverage in empiric regimens for patients with AML and persistent neutropenic fever may limit the morbidity of this pathogen., Competing Interests: Potential conflicts of interest. M. K.: royalties from UpToDate. All other authors report no potential conflicts., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: Current vancomycin guidelines recommend early and frequent area-under-the-curve monitoring in patients with obesity. Vancomycin's volume of distribution is likely altered in patients with obesity, which may result in lower serum concentrations initially but lead to accumulation with continued use. The objective of this study was to evaluate the incidence of vancomycin accumulation in patients with obesity and identify potential factors associated with accumulation., Methods: This was a single-center, retrospective, observational study at a tertiary academic medical center. Adult patients with a body mass index (BMI) ≥ 30 kg/m 2 and ≥ 2 vancomycin serum trough concentrations drawn in 2019 were screened for inclusion. The major endpoint was the incidence of vancomycin accumulation defined as ≥ 20% increase in trough concentration within the first 10 days of therapy. Key minor endpoints included incidence of acute kidney injury (AKI) and factors associated with accumulation., Results: Of the 443 patients screened, 162 were included. The median age was 56.5 years (interquartile range [IQR], 43-65.3), and 62.3% were male. The median weight was 112.7 kg (IQR, 99.8-122.6) and the median BMI was 36.8 kg/m 2 (IQR, 33.1-41). The total daily dose median at initiation was 28.7 mg/kg per day (IQR, 25.4-31.2). Accumulation occurred in 99 of 162 patients (61.1%) and AKI occurred in 20 of 140 patients (14.3%). No specific factors were found to be associated with accumulation., Conclusions: Patients with obesity are likely to experience vancomycin accumulation within the first 10 days of therapy. Clinicians should use frequent monitoring of vancomycin and use caution when interpreting early concentrations in patients with obesity., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts of interest., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: Omadacycline is an aminomethylcycline antimicrobial approved by the US Food and Drug Administration in 2018 for community-acquired bacterial pneumonia and acute bacterial skin and skin structure infections. It has in vitro activity against nontuberculous mycobacteria, including Mycobacterium abscessus complex, but clinical data for this indication are lacking., Methods: Omadacycline use was reviewed at an 804-bed academic medical center. Patients were included if they received omadacycline for culture-proven M abscessus disease in 2019., Results: Four patients received omadacycline for the treatment of culture-positive M abscessus disease in 2019. Two patients had cutaneous disease, 1 had pulmonary disease, and 1 had osteomyelitis and bacteremia. The patients received omadacycline for a median duration of 166 days (range, 104-227) along with a combination of other antimicrobial agents. Omadacycline-containing regimens were associated with a clinical cure in 3 of 4 patients, with 1 patient improving on ongoing treatment. Omadacycline's tolerability was acceptable for patients with M abscessus disease, with 1 patient discontinuing therapy in month 6 due to nausea., Conclusions: Omadacycline is a novel oral option for the treatment of M abscessus disease, for which safe and effective options are needed. Although this case series is promising, further data are required to determine omadacycline's definitive role in the treatment of M abscessus disease., (© The Author(s) 2020. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)