In Vitro Activity of Imipenem/Relebactam and Ceftolozane/Tazobactam Against Clinical Isolates of Gram-negative Bacilli With Difficult-to-Treat Resistance and Multidrug-resistant Phenotypes-Study for Monitoring Antimicrobial Resistance Trends, United States 2015-2017.

BACKGROUND: Multidrug-resistant (MDR) bacteria are frequently defined using the criteria established by Magiorakos et al [Clin Microbiol Infect 2012;18:268-81]. Difficult-to-treat resistance (DTR) [Kadri et al, Clin Infect Dis 2018;67:1803-14] is a novel approach to defining resistance in gram-negative bacilli focusing on treatment-limiting resistance to first-line agents (all ß-lactams and fluoroquinolones). METHODS: Clinical and Laboratory Standards Institute-defined broth microdilution minimum inhibitory concentrations (MICs) were determined for imipenem/relebactam, ceftolozane/tazobactam, and comparators against respiratory, intraabdominal, and urinary isolates of Enterobacterales (n = 10 516) and Pseudomonas aeruginosa (n = 2732) collected in 26 US hospitals in 2015-2017. RESULTS: Among all Enterobacterales, 1.0% of isolates were DTR and 15.6% were MDR; 8.4% of P. aeruginosa isolates were DTR and 32.4% were MDR. MDR rates for Enterobacterales and DTR and MDR rates for P. aeruginosa were significantly higher (P < .05) in isolates collected in intensive care units (ICUs) than in non-ICUs and in respiratory tract isolates than in intraabdominal or urinary tract isolates. In addition, 82.4% of DTR and 92.1% of MDR Enterobacterales and 62.2% of DTR and 82.2% of MDR P. aeruginosa were imipenem/relebactam-susceptible, and 1.5% of DTR and 65.8% of MDR Enterobacterales and 67.5% of DTR and 84.0% of MDR P. aeruginosa were ceftolozane/tazobactam-susceptible. CONCLUSIONS: MDR phenotypes defined using the Magiorakos criteria may overcall treatment-limiting resistance in gram-negative bacilli. In the US, DTR Enterobacterales were infrequent, while MDR Enterobacterales isolates and DTR and MDR P. aeruginosa were common. Imipenem/relebactam (Enterobacterales, P. aeruginosa) and ceftolozane/tazobactam (P. aeruginosa) retained in vitro activity against most DTR and MDR isolates.

A Combination Antibiogram Evaluation for Pseudomonas aeruginosa in Respiratory and Blood Sources from Intensive Care Unit (ICU) and Non-ICU Settings in U.S. Hospitals.

Pseudomonas aeruginosa is an important pathogen associated with significant morbidity and mortality. U.S. guidelines for the treatment of hospital-acquired and ventilator-associated pneumonia recommend the use of two antipseudomonal drugs for high-risk patients to ensure that ≥95% of patients receive active empirical therapy. We evaluated the utility of combination antibiograms in identifying optimal anti-P.aeruginosa drug regimens. We conducted a retrospective cross-sectional analysis of the antimicrobial susceptibility of all nonduplicate P.aeruginosa blood and respiratory isolates collected between 1 October 2016 and 30 September 2017 from 304 U.S. hospitals in the BD Insights Research Database. Combination antibiograms were used to determine in vitro rates of susceptibility to potential anti-P.aeruginosa combination regimens consisting of a backbone antibiotic (an extended-spectrum cephalosporin, carbapenem, or piperacillin-tazobactam) plus an aminoglycoside or fluoroquinolone. Single-agent susceptibility rates for the 11,701 nonduplicate P.aeruginosa isolates ranged from 72.7% for fluoroquinolones to 85.0% for piperacillin-tazobactam. Susceptibility rates were higher for blood isolates than for respiratory isolates (P < 0.05). Antibiotic combinations resulted in increased susceptibility rates but did not achieve the goal of 95% antibiotic coverage. Adding an aminoglycoside resulted in higher susceptibility rates than adding a fluoroquinolone; piperacillin-tazobactam plus an aminoglycoside resulted in the highest susceptibility rate (93.3%). Intensive care unit (ICU) isolates generally had lower susceptibility rates than non-ICU isolates. Commonly used antipseudomonal drugs, either alone or in combination, did not achieve 95% coverage against U.S. hospital P.aeruginosa isolates, suggesting that new drugs are needed to attain this goal. Local institutional use of combination antibiograms has the potential to optimize empirical therapy of infections caused by difficult-to-treat pathogens.

Antimicrobial stewardship: philosophy versus practice.

To promote the judicious use of antimicrobials and preserve their usefulness in the setting of growing resistance, a number of policy-making bodies and professional societies have advocated the development of antimicrobial stewardship programs. Although these programs have been implemented at many institutions in the United States, their impact has been difficult to measure. Current recommendations advocate the use of both outcome and process measures as metrics for antimicrobial stewardship. Although patient outcome metrics have the greatest impact on the quality of care, the literature shows that antimicrobial use and costs are the indicators measured most frequently by institutions to justify the effectiveness of antimicrobial stewardship programs. The measurement of more meaningful outcomes has been constrained by difficulties inherent to these measures, lack of funding and resources, and inadequate study designs. Antimicrobial stewardship can be made more credible by refocusing the antimicrobial review process to target specific disease states, reassessing the usefulness of current metrics, and integrating antimicrobial stewardship program initiatives into institutional quality and safety efforts.

Outcomes and metrics for antimicrobial stewardship: survey of physicians and pharmacists.

We conducted a survey to compare antimicrobial stewardship outcomes considered to be most important with those used in practice as metrics. Respondent opinion of important outcomes compared with those collected as metrics were antimicrobial use (15% vs 73%), antimicrobial cost (10% vs 73%), appropriateness of antimicrobial use (56% vs 51%), infection-related mortality rate (34% vs 7%), and antibiotic-associated length of stay (22% vs 12%). Patient outcomes are important to many practitioners but are rarely used as metrics.

Assessing appropriateness of antimicrobial therapy: in the eye of the interpreter.

To address the increase of drug-resistant bacteria and widespread inappropriate use of antimicrobials, many healthcare institutions have implemented antimicrobial stewardship programs to promote appropriate use of antimicrobials and optimize patient outcomes. However, a consensus definition of appropriate use is lacking. We conducted a multicenter observational study to compare 4 definitions of appropriateness--a study site-specific definition, use supported by susceptibility data, use supported by electronic drug information resources (Clinical Pharmacology/Micromedex), or study site principal investigator (PI) opinion-among patients receiving 1 or more of 13 identified antimicrobials. Data were collected for 262 patients. Overall, appropriateness with the 4 definitions ranged from 79% based on PI opinion to 94% based on susceptibility data. No single definition resulted in consistently high appropriate use for all target antimicrobials. For individual antimicrobials, the definitions with the highest rate of appropriate use were Clinical Pharmacology/Micromedex support (6 of 7 antimicrobials) and susceptibility data (5 of 7 antimicrobials). For specific indications, support from susceptibility data resulted in the highest rate of appropriate use (4 of 7 indications). Overall comparisons showed that appropriateness assessed by PI opinion differed significantly compared with other definitions when stratified by either target antimicrobial or indication. The significant variability in the rate of appropriate use highlights the difficulty in developing a standardized definition that can be used to benchmark judicious antimicrobial use.

Breaking down the barriers: challenges with development and implementation of an industry-sponsored antimicrobial stewardship data collection and analysis tool.

Partnership between clinicians and the pharmaceutical industry with a focus on antimicrobial stewardship research initiatives is a necessary step toward meeting the shared goals of combating inappropriate antimicrobial use, improving patient outcomes, and minimizing resistance development. Achieving these goals requires outcomes-focused data collection and monitoring tools for antimicrobial stewardship programs (ASP) that consider real-world data about how antimicrobials are used to treat patients. Here we highlight the experiences and challenges associated with the development and implementation of an industry-sponsored electronic antimicrobial stewardship data collection and analysis tool (AS-DCAT). The benefits and risks of the industry-sponsored AS-DCAT from the perspectives of the sponsoring company and participating sites are discussed. Barriers encountered as well as general considerations and recommendations for preventing or overcoming those barriers for future studies and tool development are provided.

Knowledge and attitudes of doctor of pharmacy students regarding the appropriate use of antimicrobials.

Pharmacists are key partners in antimicrobial stewardship efforts, yet their degree of education on and attitudes toward this topic during training are not well documented. An electronic survey measuring knowledge and attitudes regarding antimicrobial use and resistance was administered to graduating pharmacy students at 12 US schools of pharmacy. Of 1445 pharmacy students, 579 (40%) completed the survey. The vast majority (94%) believed that strong knowledge of antimicrobials was important for their pharmacy careers, and 89% desired more education on appropriate antimicrobial use. Most students (84%) considered their pharmacy education regarding antimicrobials useful or very useful, but there was significant variability on perceptions of preparation for most antimicrobial stewardship activities according to the students' school. The mean number of correct answers on a section of 11 knowledge questions was 5.8 (standard deviation 2.0; P value for score between schools <.001). On multivariable linear regression analysis, significant predictors of a higher knowledge score were pharmacy school attended, planned postgraduate training, completion of a clinical rotation in infectious diseases, perception of pharmacy school education as useful, use of resources to answer the knowledge questions, and use of Infectious Diseases Society of America guidelines and smartphone applications as frequent resources for learning about antimicrobials. Pharmacy students perceive antimicrobial stewardship to be an important healthcare issue and desire more education on the subject. Student perceptions of antimicrobial coursework and actual antimicrobial knowledge scores significantly varied by the school of pharmacy attended. Sharing of best practices among institutions may enhance the preparation of future pharmacists to contribute to effective antimicrobial stewardship.

Pharmacokinetics of ertapenem in critically ill patients receiving continuous venovenous hemodialysis or hemodiafiltration.

This study characterizes the pharmacokinetics of ertapenem, a carbapenem antibiotic, in critically ill adult subjects receiving continuous renal replacement therapy (CRRT). Eight critically ill patients with suspected/known Gram-negative infections receiving continuous venovenous hemodialysis (CVVHD) or continuous venovenous hemodiafiltration (CVVHDF) and ertapenem were enrolled. One gram of ertapenem was infused over 30 min. Predialyzer blood samples were drawn with the first dose of ertapenem from the hemodialysis tubing at time zero, 30 min, and 1, 2, 4, 8, 12, 18, and 24 h after the start of the ertapenem infusion. Effluent was collected at the same time points. Ertapenem total serum, unbound serum, and effluent concentrations from all eight subjects were used simultaneously to perform a population compartmental pharmacokinetic modeling procedure using NONMEM. Monte Carlo simulations were performed to evaluate the ability of several ertapenem dosing regimens (500 mg once daily, 750 mg once daily, 500 mg twice daily, and 1,000 mg once daily) to obtain effective unbound serum concentrations above 0.5, 1, and 2 µg/ml. For our simulated patients, all regimens produced unbound ertapenem concentrations above 2 µg/ml for 40% of the dosing interval for at least 96% of simulated patients. (This study has been registered at ClinicalTrials.gov under registration no. NCT00877370.).

Daptomycin pharmacokinetics in critically ill patients receiving continuous venovenous hemodialysis.

OBJECTIVE: To investigate daptomycin pharmacokinetics in critically ill patients receiving continuous venovenous hemodialysis to develop dosing recommendations. DESIGN: Prospective, open-label pharmacokinetic study. SETTING: : Intensive care units located within a teaching medical center. PATIENTS: Eight adults with known/suspected Gram-positive infections receiving continuous venovenous hemodialysis and daptomycin. INTERVENTIONS: Daptomycin at 8 mg/kg intravenously over 30 mins. Serial blood and effluent samples were collected over the next 48 hrs. Daptomycin protein binding was determined by equilibrium dialysis. Daptomycin continuous venovenous hemodialysis transmembrane clearance was determined by dividing daptomycin effluent by serum concentrations and multiplying by mean effluent production rate for each subject. Equations describing a two-compartment, open-pharmacokinetic model were fitted to each subject's daptomycin concentration-time data and pharmacokinetic parameters were determined by standard methods. Serum concentration-time profiles were simulated for two daptomycin regimens (8 mg/kg every 48 hrs and 4 mg/kg every 24 hrs). MEASUREMENTS AND MAIN RESULTS: A total of 7.7 ± 0.6 mg/kg (mean ± sd) of daptomycin was administered, resulting in an observed peak concentration of 81.2 ± 19.0 µg/mL. Daptomycin steady-state volume of distribution (0.23 ± 0.14 L/kg) and free fraction (17.5% ± 5.0%) were increased in critically ill subjects receiving continuous venovenous hemodialysis compared with previous values reported in healthy volunteers. Daptomycin transmembrane clearance (6.3 ± 2.9 mL/min) accounted for more than half of total clearance (11.3 ± 4.7 mL/min). Simulations demonstrated 8 mg/kg daptomycin every 48 hrs would result in higher peak (88.8 ± 20.0 µg/mL vs. 53.0 ± 12.3 µg/mL) and lower trough concentrations (7.2 ± 5.2 µg/mL vs. 12.3 ± 5.1 µg/mL) than 4 mg/kg every 24 hrs. CONCLUSIONS: Daptomycin at 8 mg/kg every 48 hrs in critically ill patients receiving continuous venovenous hemodialysis resulted in good drug exposure, achieved high peak concentrations to maximize daptomycin's concentration-dependent activity, and resulted in trough concentration that would minimize the risk of myopathy. CLINICALTRIALS.GOV IDENTIFIER: NCT00663403.

Ceftaroline fosamil: a novel broad-spectrum cephalosporin with activity against methicillin-resistant Staphylococcus aureus.

OBJECTIVE: To review the pharmacology, microbiology, chemistry, in vitro activity, pharmacokinetics, clinical efficacy, safety, dosage, and administration of ceftaroline fosamil (Teflaro, Forest Laboratories, Inc.), a novel parenteral broad-spectrum cephalosporin approved by the Food and Drug Administration (FDA) on October 29, 2010, for the treatment of adults with acute bacterial skin and skin structure infections (ABSSSI) and community-acquired bacterial pneumonia (CABP). DATA SOURCES: A search of MEDLINE (1966-July 2011) using the search terms ceftaroline fosamil, ceftaroline, TAK-599, PPI-0903, PPI-0903M, and T-91825 was performed. Supplementary sources included program abstracts from the Interscience Conference on Antimicrobial Agents and Chemotherapy, American Society of Microbiology, European Congress on Clinical Microbiology and Infectious Diseases, and the Infectious Diseases Society of America from 2005 to 2010, as well as information available from the manufacturer's Web site. STUDY SELECTION AND DATA EXTRACTION: All English-language articles identified from the data sources were evaluated. In vitro, preclinical, and Phase 1, 2, and 3 clinical trials were included. DATA SYNTHESIS: Clinical trials have been conducted evaluating use of ceftaroline for treatment of ABSSSI and CABP. Safety data from Phase 1, 2, and 3 clinical trials suggest that it is well tolerated and has a safety and tolerability profile common to the cephalosporin class. Ceftaroline has excellent in vitro activity against gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA), which makes it an attractive monotherapy for the treatment of ABSSSI. However, it lacks activity against problem gram-negative bacteria (eg, Pseudomonas spp.), which will likely limit its use for serious health care-associated infections. While its role in treating CABP is supported by excellent in vitro activity against Streptococcus pneumoniae and clinical efficacy data, currently available comparators may offer some advantages over ceftaroline. Finally, data are lacking to assess its role in the treatment of serious infections due to MRSA (eg, pneumonia, bacteremia). CONCLUSIONS: These considerations should be part of the formulary review process; however, when considering the significant role MRSA plays in ABSSSI in both the community and hospital settings, we believe that ceftaroline will provide clinicians with a welcome option in addition to currently available anti-MRSA therapies for the treatment of ABSSSI.

Outcomes of therapy: vancomycin-resistant enterococcal bacteremia in hematology and bone marrow transplant patients.

PURPOSE: The purpose of this study was to evaluate the risk factors associated with the treatment failure and 30-day mortality in hematology and bone marrow transplant patients treated with daptomycin or linezolid for vancomycin-resistant enterococci (VRE) bacteremia. The safety and tolerability of therapy was also assessed. METHODS: This single-center, retrospective study included adult patients admitted to the hematology or bone marrow transplant service with documented vancomycin-resistant Enterococcus faecium or Enterococcus faecalis bacteremia and received at least 48 h of either linezolid or daptomycin as primary treatment. Clinical and microbiologic outcomes were assessed at day 7, 14, and 30 of hospital stay. RESULTS: A total of 72 patients were included in the analysis. Forty-three patients received daptomycin as primary treatment and 29 received linezolid as primary treatment. Overall success rate at day 7 was 81.9%, day 14 success rate was 79.2%, and day 30 success rate was 76.4% for all patients. Forty-one patients (57.0%) had high-grade bacteremia defined as greater than one positive blood culture for VRE. The mortality rate was significantly higher if high-grade bacteremia was present (34.1% vs. 7.0%; p = 0.009). CONCLUSIONS: This study suggests that linezolid and daptomycin are both reasonable options for treating VRE bacteremia in hematology and bone marrow transplant patients; however, patients with high-grade VRE bacteremia may be at increased risk for treatment failure.

Surgical infection prophylaxis for left ventricular assist device implantation.

BACKGROUND: Antimicrobial prophylaxis is commonly administered to patients undergoing left ventricular assist device (LVAD) surgeries to prevent infectious complications. However, optimal surgical infection prophylaxis (SIP) for LVAD surgeries is not well defined. METHODS: We conducted an electronic survey to characterize LVAD SIP used at different centers performing LVAD implantation. RESULTS: Responses were received from 23 of 85 centers (27%). Of 21 centers that provided usable data about their LVAD SIP regimens for nonpenicillin allergic patients, 42.9% reported using a four-drug regimen (three antibiotics plus fluconazole), 23.8% reported using a three-drug regimen (three antibiotics or two antibiotics plus fluconazole), 23.8% reported using a regimen of two antibiotics, and 9.5% reported using vancomycin alone. A similar pattern was observed among SIP regimens for penicillin-allergic patients. Criteria for discontinuation of SIP and use of decolonization strategies also varied widely across centers. CONCLUSIONS: Our results demonstrate wide variability in LVAD SIP regimens and underscore the lack of consensus regarding best practice.

Epidemiology and regional variation of nonsusceptible and multidrug-resistant Pseudomonas aeruginosa isolates from intensive versus non-intensive care units across multiple centers in the United States.

Nonsusceptible (NS) and multidrug-resistant (MDR) Pseudomonas aeruginosa (PsA) infections are associated with considerable mortality. This retrospective study assessed NS PsA and MDR PsA prevalence in US intensive care unit (ICU) and non-ICU settings. We evaluated nonduplicate PsA isolates collected in 2017. Data were classified by hospital admission setting. PsA isolates were evaluated for NS to each of 4 drug classes and MDR. Significantly higher rates of NS PsA and MDR PsA were found in ICU versus non-ICU settings (P < .001), except for respiratory isolates, which had high rates regardless of setting; rates also correlated with source, hospital size, urban/rural status, and geographic region. NS PsA isolates for each antibacterial category (except fluoroquinolones) and MDR PsA were significantly more likely to be classified as hospital-onset than admission-onset (P < .001). These data are consistent with previous reports and emphasize the importance of testing for resistant infection upon admission and when treating hospital-acquired infections.

Ceftolozane/Tazobactam and Imipenem/Relebactam Cross-Susceptibility Among Clinical Isolates of Pseudomonas aeruginosa From Patients With Respiratory Tract Infections in ICU and Non-ICU Wards-SMART United States 2017-2019.

BACKGROUND: Carbapenem-nonsusceptible and multidrug-resistant (MDR) P. aeruginosa, which are more common in patients with lower respiratory tract infections (LRTIs) and in patients in intensive care units (ICUs), pose difficult treatment challenges and may require new therapeutic options. Two ß-lactam/ß-lactamase inhibitor combinations, ceftolozane/tazobactam (C/T) and imipenem/relebactam (IMI/REL), are approved for treatment of hospital-acquired/ventilator-associated bacterial pneumonia. METHODS: The Clinical and Laboratory Standards Institute-defined broth microdilution methodology was used to determine minimum inhibitory concentrations (MICs) against P. aeruginosa isolates collected from patients with LRTIs in ICUs (n = 720) and non-ICU wards (n = 914) at 26 US hospitals in 2017-2019 as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART) surveillance program. RESULTS: Susceptibility to commonly used ß-lactams including carbapenems was 5-9 percentage points lower and MDR rates 7 percentage points higher among isolates from patients in ICUs than those in non-ICU wards (P < .05). C/T and IMI/REL maintained activity against 94.0% and 90.8% of ICU isolates, respectively, while susceptibility to all comparators except amikacin (96.0%) was 63%-76%. C/T and IMI/REL inhibited 83.1% and 68.1% of meropenem-nonsusceptible (n = 207) and 71.4% and 65.7% of MDR ICU isolates (n = 140), respectively. Among all ICU isolates, only 2.5% were nonsusceptible to both C/T and IMI/REL, while 6.7% were susceptible to C/T but not to IMI/REL and 3.5% were susceptible to IMI/REL but not to C/T. CONCLUSIONS: These data suggest that susceptibility to both C/T and IMI/REL should be considered for testing at hospitals, as both agents could provide important new options for treating patients with LRTIs, especially in ICUs where collected isolates show substantially reduced susceptibility to commonly used ß-lactams.

Antimicrobial stewardship and antibiograms: importance of moving beyond traditional antibiograms.

The rapid evolution of resistance, particularly among Gram-negative bacteria, requires appropriate identification of patients at risk followed by administration of appropriate empiric antibiotic therapy. A primary tenet of antimicrobial stewardship programs (ASPs) is the establishment of empiric antibiotic recommendations for commonly encountered infections. An important tool in providing empiric antibiotic therapy recommendations is the use of an antibiogram. While the majority of institutions use a traditional antibiogram, ASPs have an opportunity to enhance antibiogram data. The authors provide the rationale for why ASPs should implement alternative antibiograms, and the importance of incorporating an antibiogram into clinical decision support systems with the goal of providing effective empiric antibiotic therapy.

Ceftolozane-tazobactam activity against clinical isolates of Pseudomonas aeruginosa from ICU patients with pneumonia: United States, 2015-2018.

OBJECTIVES: To report on the activity of ceftolozane-tazobactam and comparators against Pseudomonas aeruginosa isolates collected from hospitalized patients with pneumonia in US intensive care units (ICUs) between 2015 and 2018. Activity against all P. aeruginosa and common resistant phenotypes are described to better inform decision-making and support antimicrobial stewardship efforts. METHODS: In total, 781 P. aeruginosa isolates were collected from 28 US hospitals. These isolates were tested for susceptibility to ceftolozane-tazobactam and comparators by Clinical and Laboratory Standards Institute (CLSI) broth microdilution methodology using CLSI (2020) breakpoints. Phenotypes analysed included piperacillin-tazobactam-non-susceptible (NS), cefepime-NS, ceftazidime-NS, meropenem-NS and difficult-to-treat resistance (DTR). RESULTS: Ceftolozane-tazobactam was the most potent agent tested (minimum inhibitory concentration to inhibit 50% and 90% of isolates of 0.5 and 2 mg/L, respectively, inhibiting 97.2% at the susceptible breakpoint of ≤4 mg/L). Traditional first-line antipseudomonal ß-lactam antibiotics (piperacillin-tazobactam, cefepime and ceftazidime) demonstrated <33% susceptibility when P. aeruginosa was NS to one or more agent. Although escalation of therapy to meropenem is commonly employed clinically, meropenem susceptibility ranged from 33.6% to 44.9% if P. aeruginosa was NS to any traditional first-line antipseudomonal ß-lactam agent. Conversely, ceftolozane-tazobactam remained active against isolates that were NS to other agents, inhibiting 88.4% of isolates NS to piperacillin-tazobactam, 85.0% of isolates NS to cefepime and ceftazidime, and 90.3% of isolates NS to meropenem. Ceftolozane-tazobactam also maintained activity against 73.0% of DTR isolates. CONCLUSIONS: Ceftolozane-tazobactam maintained high activity against P. aeruginosa isolated from hospitalized patients with pneumonia in US ICUs, and had the greatest activity against isolates NS to one or more antipseudomonal ß-lactams and DTR isolates.

Managing antimicrobial resistance in intensive care units.

The challenges in managing patients with infection in the intensive care unit are increased in an era where there are dwindling antimicrobial choices for multidrug-resistant pathogens. Clinicians in the intensive care unit must balance between choosing appropriate antimicrobial treatment for patients with suspected infection and utilizing antimicrobials in a judicious fashion. Improving antimicrobial utilization is a critical component to reducing antimicrobial resistance. Although providing effective antimicrobial therapy and improving antimicrobial utilization may seem to be competing goals, there are effective strategies to accomplish both. Antimicrobial stewardship programs provide an organized way to implement these strategies and can enhance the intensive care unit physician's success in improving patient outcomes and combating antimicrobial resistance in the intensive care unit.

Factors associated with seroconversion after standard dose hepatitis B vaccination and high-dose revaccination among HIV-infected patients.

BACKGROUND: Patients with HIV-infection often respond poorly to vaccination. We sought to determine rates of seroconversion among HIV-infected patients receiving the hepatitis B vaccine and for non-responders who received high-dose revaccination. METHODS: A single-center retrospective chart review was performed. Patients received either a series of Engerix-B (20 mcg) or Twinrix (standard dose vaccine [SDV]). A subset of non-responders received a higher 40 mcg dose series of Engerix-B (high-dose revaccination [HDR]). RESULTS: 215 patients received SDV with an overall response rate of 46.5%. Among the 115 non-responders, 30 received HDR with an overall response rate of 66.7%. Factors associated with response to SDV included younger age (odds ratio [OR]/1 year=0.97, P=.03), higher CD4 at first dose (OR/100 CD4=1.13, P=.02), and receipt of Twinrix versus Engerix-B (OR=2.3, P=.003). Higher CD4 at first dose was also associated with response to HDR (OR/100 CD4=2.0, P=.02). All factors remained independently associated with response to SDV and HDR on multivariable analysis. CONCLUSIONS: HDR appears to be a viable strategy to achieve seroconversion among HIV-infected patients who fail to respond to SDV. Higher CD4 at vaccination, younger age, and receipt of Twinrix were independently associated with SDV seroconversion.

Modeled dalbavancin transmembrane clearance during intermittent and continuous renal replacement therapies.

BACKGROUND/AIMS: Knowledge of dalbavancin renal replacement therapy (RRT) disposition is vital to ensure appropriate dosing. In vitro models of continuous RRT and intermittent hemodialysis (IHD) were used to determine dalbavancin transmembrane clearance (CLtm). METHODS: Dalbavancin saturation and sieving coefficients (SCs) were determined for hemodialysis and hemofiltration therapies, respectively, using various hemodiafilter and effluent rate combinations. Dalbavancin CLtm estimates were calculated from observed saturation and SCs. RESULTS: Saturation and SCs for both modalities of continuous dialysis and hemofiltration and IHD with high permeability hemodiafilters were small. Nonetheless, during continuous RRT with high dialysate and ultrafiltration rates, dalbavancin CLtm (0.20-1.26 ml/min) matched and often exceeded literature-derived dalbavancin renal clearances. Dalbavancin CLtm was undetectable during IHD with low-permeability hemodialyzers, but with high-permeability hemodialyzers, substantial CLtm (1.90-2.43 ml/min) was noted. CONCLUSION: Dalbavancin CLtm is dependent on RRT modality, hemodiafilter, and effluent flow. Dalbavancin doses may need to be adjusted depending on RRT parameters.

Evaluation of Renal Safety Between Imipenem/Relebactam and Colistin Plus Imipenem in Patients With Imipenem-Nonsusceptible Bacterial Infections in the Randomized, Phase 3 RESTORE-IMI 1 Study.

BACKGROUND: In the randomized controlled RESTORE-IMI 1 clinical trial (NCT02452047), imipenem/cilastatin (IMI) with relebactam (IMI/REL) was as effective as colistin plus IMI for the treatment of imipenem-nonsusceptible gram-negative infections. Differences in nephrotoxicity were observed between treatment arms. As there is no standard definition of nephrotoxicity used in clinical trials, we conducted analyses to further understand the renal safety profile of both treatments. METHODS: Nephrotoxicity was retrospectively evaluated using 2 acute kidney injury assessment criteria (Kidney Disease Improving Global Outcomes [KDIGO] and Risk, Injury, Failure, Loss, and End-stage Kidney Disease [RIFLE]). Additional outcomes included time to onset of protocol-defined nephrotoxicity and incidence of renal adverse events. RESULTS: Of 47 participants receiving treatment, 45 had sufficient data to assess nephrotoxicity (IMI/REL, n = 29; colistin plus IMI, n = 16). By KDIGO criteria, no participants in the IMI/REL but 31.3% in the colistin plus IMI group experienced stage 3 acute kidney injury. No IMI/REL-treated participants experienced renal failure by RIFLE criteria, vs 25.0% for colistin plus IMI. Overall, the time to onset of nephrotoxicity varied considerably (2-22 days). Fewer renal adverse events (12.9% vs 37.5%), including discontinuations due to drug-related renal adverse events (0% vs 12.5%), were observed in the IMI/REL group compared with the colistin plus IMI group, respectively. CONCLUSIONS: Our analyses confirm the findings of a preplanned end point and provide further evidence that IMI/REL had a more favorable renal safety profile than colistin-based therapy in patients with serious, imipenem-nonsusceptible gram-negative bacterial infections. CLINICALTRIALSGOV IDENTIFIER: NCT02452047.