Pharmacokinetic evaluation of cefiderocol for the treatment of multidrug resistant Gram-negative infections.

INTRODUCTION: Cefiderocol is a siderophore cephalosporin antibiotic and first of its kind approved by the Food and Drug Administration for the treatment of complicated urinary tract infections (cUTI) and hospital-acquired and ventilator-associated bacterial pneumonia (HABP/VABP) in patients 18 years or older caused by susceptible organisms. Cefiderocol's unique mechanism of iron chelation improves Gram-negative membrane penetration as the bacteria's iron uptake mechanism recognizes the chelated iron antibiotic and iron for entry. This also allows for the evasion of cefiderocol from cell entry-related resistance mechanisms. AREAS COVERED: This review covers the mechanism of action, resistance mechanisms, pharmacokinetics in various patient populations, and pharmacodynamics. Relevant literature evaluating efficacy and safety are discussed. EXPERT OPINION: Limited treatment options are available for the treatment of carbapenem-resistantorganisms. Clinical trials have demonstrated that cefiderocol is no worse than alternative treatment options for cUTIs and HABP/VABP, but more data are currently available to support the use of beta-lactam beta-lactamase inhibitor agents, where susceptible. Mortality differences demonstrated in patients with pneumonia and bloodstream infections must further be explored and logistical and practical considerations regarding susceptibility testing and use as monotherapy vs. combination therapy must be considered prior to confidently recommending cefiderocol for regular use in systemic infections.

Evaluation of Treatment Practices for Urinalyses and Urine Cultures at an Outpatient Multiple Sclerosis Clinic.

BACKGROUND: Patients with multiple sclerosis (MS) experience disease flares that can be precipitated by the presence of infection. Discerning asymptomatic bacteriuria from urinary tract infection (UTI) in patients with MS is complicated by lower urinary tract dysfunction, leading to potentially inappropriate antimicrobial use. In this study the antimicrobial treatment practices for positive urine cultures in patients with MS were evaluated. METHODS: In this single-center, retrospective study, positive cultures in patients with MS were included. The primary outcome was the proportion of patients appropriately treated with or without antimicrobial therapy. Secondary end points included antimicrobial selection and urinalysis positivity. RESULTS: Two hundred thirty-six cultures from 139 patients were evaluated. Treatment was inappropriate in 81 of 201 treated cultures (40%). Frequency, nocturia, dysuria, and foul-smelling urine were reported by patients in 54 (23%), 10 (4%), 25 (11%), and 14 (6%) cultures, respectively. The antimicrobial selected was too broad in spectrum for 35 of 201 (17%). Of those, fluoroquinolones were the agents used in 33 of 35 cases (94%). A urinalysis was sent in 203 cases (86%), with 197 (84%) positive for at least one predefined positivity criteria. CONCLUSIONS: Urinalyses and urine cultures are performed frequently in patients with MS, often independent of symptoms. Patients with MS could be treated for asymptomatic bacteriuria at higher rates than the general population, and traditional urinary symptoms may not be appropriate indicators of infection. Empirical therapy for UTI is frequently used in this population, often resulting in inappropriate and/or too broad of antimicrobial therapy.

Contemporary Perspective on the Treatment of Acinetobacter baumannii Infections: Insights from the Society of Infectious Diseases Pharmacists.

The purpose of this narrative review is to bring together the most recent epidemiologic, preclinical, and clinical findings to offer our perspective on best practices for managing patients with A. baumannii infections with an emphasis on carbapenem-resistant A. baumannii (CRAB). To date, the preferred treatment for CRAB infections has not been defined. Traditional agents with retained in vitro activity (aminoglycosides, polymyxins, and tetracyclines) are limited by suboptimal pharmacokinetic characteristics, emergence of resistance, and/or toxicity. Recently developed and US Food and Drug Administration (FDA)-approved ß-lactam/ß-lactamase inhibitor agents do not provide enhanced activity against CRAB. On balance, cefiderocol and eravacycline demonstrate potent in vitro activity and are well tolerated, but clinical data for patients with CRAB infections do not yet support widespread use. Given that CRAB has the capacity to infect vulnerable patients and preferred regimens have not been identified, we advocate for combination therapy. Our preferred regimen for critically ill patients infected, or considered to be at high risk for CRAB, includes meropenem, polymyxin B, and ampicillin/sulbactam. Importantly, site of infection, severity of illness, and local epidemiology are essential factors to be considered in selecting combination therapies. Molecular mechanisms of resistance may unveil preferred combinations at individual centers; however, such data are often unavailable to treating clinicians and have not been linked to improved clinical outcomes. Combination strategies may also pose an increased risk for antibiotic toxicity and Clostridioides difficile infection, and should therefore be balanced by understanding patient goals of care and underlying health conditions. Promising therapies that are in clinical development and/or under investigation include durlobactam-sulbactam, cefiderocol combination regimens, and bacteriophage therapy, which may over time eliminate the need for the continued use of polymyxins. Future goals for CRAB management include pathogen-focused treatment paradigms that are based on molecular mechanisms of resistance, local susceptibility rates, and the availability of well-tolerated, effective treatment options.

A practical guide for pharmacists to successfully implement penicillin allergy skin testing.

PURPOSE: The purpose of this article is to offer practical guidance for pharmacists to successfully implement penicillin allergy skin testing (PAST). SUMMARY: Less than 10% of patients labeled as having a penicillin allergy are confirmed as present upon skin testing. This labeling results in use of alternative antibiotics and thus unwanted adverse consequences including potentiated antimicrobial resistance, increased costs, and worse clinical outcomes. Stewardship guidelines recommend PAST to enhance use of first-line agents; however, this was a weak recommendation with low-quality evidence. Recent efforts and subsequent research since publication of guidelines have demonstrated beneficial effects from increasing use of PAST among stewardship programs to improve outcomes. A number of different models exist demonstrating successful implementation of PAST at various healthcare facilities. There are important logistical factors to consider during implementation of PAST such as target population, optimal preparation, leadership structure, resource availability, and state regulations. Pharmacists as leaders of antimicrobial stewardship teams and experts in drug allergies are a natural fit to help implement PAST in healthcare settings to improve overall outcomes. This article offers guidance to institutions considering implementation of PAST. CONCLUSION: PAST is rapidly becoming an effective, long-term antimicrobial stewardship tool to optimize antimicrobial prescribing in both the inpatient and outpatient settings. Pharmacists have demonstrated significant benefit as providers of PAST services in a variety of healthcare settings with a number of different healthcare professionals.