Identification and Antibiotic Susceptibility Patterns of Clinical Blood Culture Isolates Not Identified by a Rapid Microarray Diagnostic System.

The use of molecular-based diagnostic testing, such as the Luminex Verigene system, to rapidly identify the most common bacterial isolates from blood cultures is an important tool that reduces the duration of inappropriate antibiotics and decreases mortality. However, 5 to 15% of microorganisms recovered from blood culture are unable to be identified by the Verigene Gram-negative (BC-GN) or Gram-positive (BC-GP) assays. In this retrospective, observational study, we evaluate the identities and antimicrobial susceptibility patterns of 229 isolates that were not identified by either the Verigene BC-GN or BC-GP assay. The results presented here suggest that important, clinically relevant information about antimicrobial susceptibility patterns can still be inferred even when isolates are not identified by Verigene. We also examined changes in antibiotic use for patients with "unidentified" Verigene results at our institution and found that this subgroup represents an opportunity to optimize empirical antibiotic therapy. IMPORTANCE Rapid diagnostic testing to identify bloodstream pathogens has arisen as an important tool both to ensure adequate antimicrobial therapy is given early and to aid in antimicrobial stewardship by allowing for more rapid deescalation of inappropriate antimicrobial therapy. However, there is a paucity of data regarding the significance of isolates that are not able to be identified by rapid diagnostic testing. In this study, we report the identification to the species level and antimicrobial susceptibilities among isolates that were not identified by one such rapid diagnostic platform, the Verigene system. This study provides important insight into how a strong understanding of the strengths and limitations of a given rapid diagnostic platform, coupled with insight into local antibiotic susceptibility patterns, can allow for more nuanced and thoughtful empirical antibiotic selection.

Development of the Three Antimicrobial Stewardship E's (TASE) Framework and Association Between Stewardship Interventions and Intended Results Analysis to Identify Key Facility-Specific Interventions and Strategies for Successful Antimicrobial Stewardship.

BACKGROUND: Successful antimicrobial stewardship (AS) interventions have been described previously. Currently, a uniform operational approach to planning and implementing successful AS interventions does not exist. From 2015 to 2019, concomitant vancomycin and piperacillin-tazobactam use (CVPTU) for >48 hours at Vanderbilt University Medical Center (VUMC) significantly decreased through AS efforts. We analyzed the interventions that led to this change and created a model to inform future intervention planning and development. METHODS: Adult admissions at VUMC from January 2015 to August 2019 were evaluated for CVPTU. The percentage of admissions receiving CVPTU for >48 hours, the primary outcome, was evaluated using statistical process control charts. We created the Three Antimicrobial Stewardship E's (TASE) framework and Association between Stewardship Interventions and Intended Results (ASIR) analysis to assess potential intensity and impact of interventions associated with successful change during this time period and to identify guiding principles for development of future initiatives. RESULTS: The mean percentage of admissions receiving CVPTU per month declined from 4.2% to 0.7%. Over 8 time periods, we identified 4 periods with high, 3 with moderate, and 1 with low intervention intensity. Continuous provider-level AS education was present throughout. Creation and dissemination of division and department algorithms and reinforcement via computerized provider order entry sets preceded the largest reduction in CVPTU and sustained prescribing practice changes. CONCLUSIONS: The TASE framework and ASIR analysis successfully identified pivotal interventions and strategies needed to effect and sustain change at VUMC. Further research is needed to validate the effectiveness of this framework as a stewardship intervention planning tool at our institution and others.

Antimicrobial de-escalation in patients with high-risk febrile neutropenia: Attitudes and practices of adult hospital care providers.

In a survey of adult hospital providers regarding antibiotic use in the treatment of febrile neutropenia, clinical fellows, and pharmacists showed higher comfort levels with early antimicrobial de-escalation compared to hematology-oncology and transplant infectious diseases physicians. These frontline team members are ideal partners to champion antimicrobial stewardship interventions in febrile neutropenia.

Description of a pharmacist-driven safety algorithm in Staphylococcus aureus bacteremia: Compliance, interventions, and good saves.

OBJECTIVE: To evaluate the impact of a pharmacist-driven Staphylococcus aureus bacteremia (SAB) safety bundle supported by leadership and to compare compliance before and after implementation. DESIGN: Retrospective cohort study with descriptive and before-and-after analyses. SETTING: Tertiary-care academic medical center. PATIENTS: All patients with documented SAB, regardless of the source of infection, were included. Patients transitioned to palliative care were excluded from before-and-after analysis. METHODS: A pharmacist-driven safety bundle including documented clearance of bacteremia, echocardiography, removal of central venous catheters, and targeted intravenous therapy of at least 2 weeks duration was implemented in November 2015 and was supported by leadership with stepwise escalation for nonresponse. A descriptive analysis of all patients with SAB during the study period included pharmacy interventions, acceptance rates, and escalation rates. A pre-post implementation analysis of 100 sequential patients compared bundle compliance and descriptive parameters. RESULTS: Overall, 391 interventions were made in the 20-month period following implementation, including 20 "good saves" avoiding potentially major adverse events. No statistically significant differences in complete bundle compliance were detected between the periods (74% vs 84%; P = .08). However, we detected a significant increase in echocardiography after the bundle was implemented (83% vs 94%; P = .02) and fewer patients received suboptimal definitive therapy after the bundle was implemented (10% vs 3%; P = .045). CONCLUSIONS: This pharmacist-driven SAB safety bundle with leadership support showed improvement in process measures, which may have prevented major adverse events, even with available infectious diseases (ID) consultation. It provides a critical safety net for institutions without mandatory ID consultation or with limited antimicrobial stewardship resources.

Minimum inhibitory concentration changes in relapsed left ventricular assist device driveline infections.

Driveline infection is the most common infectious complication in patients with left ventricular assist devices. Minimum inhibitory concentration changes are not well described in relapsed driveline infections. This retrospective descriptive epidemiology study of patients with left ventricular assist device implantation between January 1, 2013, and August 1, 2017, who developed driveline infection with positive cultures aimed to describe minimum inhibitory concentration changes. Of the 330 patients underwent left ventricular assist device implantation, 30 (9%) met criteria for driveline infection. Median duration of follow-up was 26 months (interquartile range 16, 39) and time to first driveline infection was 171 days (interquartile range 83, 403). There were 74 driveline infections: 40 new and 34 relapsed. Staphylococcus aureus was most common in new and relapsed driveline infection. Thirteen patients comprised the 34 relapsed infections, 9 of which experienced a minimum inhibitory concentration change. Median time to first minimum inhibitory concentration change was 56 days (interquartile range 36-88), and type of minimum inhibitory concentration change was an increase in five cases, decrease in two cases, and both increase and decrease in two cases. Minimum inhibitory concentration changes did not result in resistance in S. aureus but did in Pseudomonas aeruginosa and Mycobacterium fortuitum relapsed driveline infection. Time to first relapse from initial infection was longer in those who received suppressive therapy, 60 days versus 83 days, p = 0.047. Relapsed driveline infections were most common with S. aureus. Minimum inhibitory concentration changes were quite variable and may not be the major contributor to relapsed infection in gram-positive driveline infection.

Antimicrobial stewardship staffing: How much is enough?

Antimicrobial stewardship improves patient care and reduces antimicrobial resistance, inappropriate use, and adverse outcomes. Despite high-profile mandates for antimicrobial stewardship programs across the healthcare continuum, descriptive data, and recommendations for dedicated resources, including appropriate physician, pharmacist, data analytics, and administrative staffing support, are not robust. This review summarizes the current literature on antimicrobial stewardship staffing and calls for the development of minimum staffing recommendations.

Risk Factors and Outcomes Associated With Acquisition of Daptomycin and Linezolid-Nonsusceptible Vancomycin-Resistant Enterococcus.

BACKGROUND: Vancomycin-resistant enterococcus (VRE) causes substantial health care-associated infection with increasing reports of resistance to daptomycin or linezolid. We conducted a case-control study reporting 81 cases of daptomycin and linezolid-nonsusceptible VRE (DLVRE), a resistance pattern not previously reported. METHODS: We reviewed VRE isolates from June 2010 through June 2015 for nonsusceptibility to both daptomycin (minimum inhibitory concentration [MIC] > 4) and linezolid (MIC ≥ 4). We matched cases by year to control patients with VRE susceptible to both daptomycin and linezolid and performed retrospective chart review to gather risk factor and outcome data. RESULTS: We identified 81 DLVRE cases. Resistance to both daptomycin and linezolid was more common than resistance to either agent individually. Compared with susceptible VRE, DLVRE was more likely to present as bacteremia without focus (P < 0.01), with DLVRE patients more likely to be immune suppressed (P = .04), to be neutropenic (P = .03), or to have had an invasive procedure in the prior 30 days (P = .04). Any antibiotic exposure over the prior 30 days conferred a 4-fold increased risk for DLVRE (odds ratio [OR], 4.25; 95% confidence interval [CI], 1.43-12.63; P = .01); multivariate analysis implicated daptomycin days of therapy (DOT) over the past year as a specific risk factor (OR, 1.10; 95% CI, 1.01-1.19; P = .03). DLVRE cases had longer hospitalizations (P = .04) but no increased risk for in-hospital death. CONCLUSIONS: DLVRE is an emerging multidrug-resistant pathogen associated with immune suppression, neutropenia, and recent invasive procedure. Prior antibiotic exposure, specifically daptomycin exposure, confers risk for acquisition of DLVRE.

Driving antimicrobial use improvement: attitudes of providers of adult hospital care on optimal attribution and feedback.

Understanding provider perceptions of antimicrobial use (AU) feedback is important for optimal implementation. A survey addressing AU attribution scenarios, feedback methods, and implementation barriers was distributed to inpatient providers. As AU scenarios became more complex, disagreement regarding AU attribution arose. All providers were highly concerned about barriers to AU reporting.

Posaconazole-Induced Pseudohyperaldosteronism.

A woman in her late 60s with disseminated histoplasmosis was treated with posaconazole because first-line therapies were not tolerated. She subsequently presented with decompensated heart failure, hypertension, and hypokalemia. Laboratory tests revealed low renin and aldosterone levels. A potential mechanism is inhibition of the enzyme 11ß-hydroxysteroid dehydrogenase 2, with resultant apparent mineralocorticoid excess.